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The umbilical cord (UC), the connection between mother and fetus via the umbilical vessels, carries nutrients and oxygenated blood to the fetus through the umbilical vein and removes deoxygenated blood and waste products via the umbilical arteries. It is designed to protect blood flow to the fetus during pregnancy. In equine medicine, only a few studies have described the UC, and most of these involved Thoroughbreds. The present study describes and compares the macroscopic features of the equine umbilical cord in three different breeds and in relation to the foal's gender. In addition, a possible correlation between UC features and maternal and perinatal factors is investigated. One hundred and twenty four healthy mares with normal pregnancies were enrolled in the study and were divided into three groups according to their breed: 70 Standardbreds (STB), 38 Thoroughbreds (THB) and 16 Warmbloods (WAB). The following data were recorded: mare's age and parity, gestation length, placental weight, presence of fetal membrane alterations, UC length and number of coils in the amniotic and allantoic portions, and the Umbilical Coiling Index (UCI), which is the ratio between total coils and total UC length. The UCI has not been investigated previously in veterinary medicine. Furthermore, immediately after foaling, APGAR score, foal's weight and sex were recorded. All the STB and WAB were housed in Italy and the THB were housed in New Zealand. Mares' mean age was higher in WAB than in THB and STB; the latter had a significantly shorter gestation length. The foal's weight was positively correlated with placental weight in all breeds; and in STB, foal weight was positively related to parity and gestation length. Mean total UC length was comparable to previous reports in THB, STB and WAB. The lengths of the two UC portions were statistically different between STB and THB, where the amniotic portion was longer than the allantoic one. In each breed, total UC length was correlated with total number of coils (THB and STB = 5 ± 1; WAB = 6 ± 1), the UC amniotic length was positively correlated with the number of amniotic coils and the allantoic length was positively correlated with the number of allantoic coils. The UCI values were 0.09 in STB and THB and 0.1 in WAB. This study provides reference values for UCI that could be included in the gross placental evaluation if its clinical importance were demonstrated., (Copyright © 2018. Published by Elsevier Inc.)

Mothers of alleged infanticides might claim that umbilical cord broke during precipitate delivery causing injuries detected on baby at autopsy. There is paucity of evidence regarding this possibility. The objective of the study was to determine relationship between tensile strength and diameter or weight per unit length of cord. Diameters and weights per unit length of fresh umbilical cords were determined. Tensile strengths were measured by Hounsfield Testing Machine. Relationship between tensile strength versus cord diameter and weight per unit length were analyzed. Of 122 cords, average tensile strength, diameter and weight per centimeter were 50.4 N, 7.73 mm and 6.87 g respectively. The tensile strengths were directly proportional to diameter. There was no association between tensile strength and weight per centimeter. Measurement of the diameter of cord is important during autopsy to predict tensile strength and thereby to presume whether cord could have broken by the weight of the baby., (Copyright © 2018 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.)

Introduction: We established reference values for placental weight, birth weight, and fetal:placental weight ratio (FPR) (a possible index of placental functional efficiency) in monochorionic and dichorionic twin gestations., Methods: Placental weight, birth weight, and FPR in function of gestational age, cord insertion type and placental sharing were determined in 151 dye-injected diamniotic-monochorionic and 198 double-disc diamniotic-dichorionic twin placentas (25-39 weeks' gestation)., Results: As expected, FPR values increased with gestational age in both groups. Birth weights and placental weights of monochorionic twins >28 weeks' gestation were significantly lower than those of age-matched dichorionic twins. When stratified per placental weight, the birth weights and FPR values of monochorionic twins were overall lower than those of dichorionic twins within the same placental weight category. However, in the subset of monochorionic twins with small share in unevenly partitioned placentas, birth weights and FPR values per placental weight were similar to those of dichorionic twins, and significantly higher than those of monochorionic twins with larger share or even placental sharing. Cord insertion type did not correlate with birth weight or FPR values per placental weight in either twin type., Discussion: Reference values were generated for placental weight, birth weight and FPR in monochorionic and double-disc dichorionic twins. The generally lower FPR per placental weight in monochorionic twins compared with dichorionic twins is suggestive of inherently lower placental functional efficiency in monochorionic gestations. The mechanisms and clinical implications of the apparent differential modulation of FPR/efficiency in monochorionic twins according to placental partitioning remain to be determined., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Introduction: Many complications of pregnancy and delivery are associated with umbilical cord length. It is important to examine the variation in length, in order to identify normal and abnormal conditions. Moreover, the factors influencing cord growth and development are not precisely known., Objective: The main objectives were to provide updated reference charts for umbilical cord length in singleton pregnancies and to evaluate potential factors affecting cord length., Methods: Birth register data of 47,284 singleton pregnant women delivering in Kuopio University Hospital, Finland was collected prospectively. Gender-specific centile charts for cord length from 22 to 44 gestational weeks were obtained using generalized additive models for location, scale, and shape (GAMLSS). Gestational, fetal, and maternal factors were studied for their potential influence on cord length with single variable analysis and stepwise multiple linear regression analysis., Results: Cord length increased according to gestational age, while the growth decelerated post-term. Birth weight, placental weight, pregravid maternal body mass index, parity, and maternal age correlated to cord length. Gestational diabetes and previous miscarriages were associated with longer cords, while female gender and placental abruption were associated with shorter cords., Discussion and Conclusions: Girls had shorter cords throughout gestation although there was substantial variation in length in both genders. Cord length associated significantly with birth weight, placental weight, and gestational age. Significantly shorter cords were found in women with placental abruption. This important finding requires further investigation., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Introduction: Studies on developmental programming rely on various measures of size and form of the human placenta. Size and form are not independent of each other and covariation patterns were not determined systematically., Methods: Twenty-two morphologic parameters were determined on 418 placentas from uncomplicated singleton pregnancies. We determined (i) placenta weight and birth weight, (ii) form parameters such as diameters, thickness, roundness, and eccentricity of cord insertion, and (iii) shape variability by geometric morphometry. Geometric morphometry analyzes shape variability independent of size. We define the technical terms form and shape according to the language of geometric morphometry., Results: Placenta weight correlated with birth weight. The form parameters correlated variably with placenta weight and shape. Shape variability did not correlate with birth weight and placenta weight., Discussion and Conclusions: The correlation of placenta weight with birth weight stays a cornerstone of prenatal programming. Shape analysis shows that form parameters are hybrids of size and shape. Shape variability can be interpreted as an outcome of adaptation of a placenta to maternal factors and the associated uterine habitat. Correlation analysis of the whole data array provides a rigorous statistical frame to interpret published data and plan new studies., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Introduction: While the mean shape of human placenta is round with centrally inserted umbilical cord, significant deviations from this ideal are fairly common, and may be clinically meaningful. Traditionally, they are explained by trophotropism. We have proposed a hypothesis explaining typical variations in placental shape by randomly determined fluctuations in the growth process of the vascular tree. It has been recently reported that umbilical cord displacement in a birth cohort has a log-normal probability distribution, which indicates that the displacement between an initial point of origin and the centroid of the mature shape is a result of accumulation of random fluctuations of the dynamic growth of the placenta. To confirm this, we investigate statistical distributions of other features of placental morphology., Methods: In a cohort of 1023 births at term digital photographs of placentas were recorded at delivery. Excluding cases with velamentous cord insertion, or missing clinical data left 1001 (97.8%) for which placental surface morphology features were measured. Best-fit statistical distributions for them were obtained using EasyFit., Results and Discussion: The best-fit distributions of umbilical cord displacement, placental disk diameter, area, perimeter, and maximal radius calculated from the cord insertion point are of heavy-tailed type, similar in shape to log-normal distributions. This is consistent with a stochastic origin of deviations of placental shape from normal., Conclusions: Deviations of placental shape descriptors from average have heavy-tailed distributions similar in shape to log-normal. This evidence points away from trophotropism, and towards a spontaneous stochastic evolution of the variants of placental surface shape features., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Background: Recent evidence suggests that cord insertion type of one twin correlates with chorionic plate vascularization of the monochorionic co-twin. Specifically, for twins with paracentral cords, chorionic plate vascularization is significantly greater when the co-twin has a velamentous, rather than paracentral cord insertion., Aims: To determine whether this correlation between cord insertion type and vascularization of the co-twin also extends to the deeper chorionic villus tree., Study Design: Morphometric analysis of chorionic villus vascularization in CD31-immunostained sections of a retrospective cohort of gestational age-matched third trimester monochorionic placentas with discordant paracentral/velamentous (PC/V) or concordant paracentral/paracentral (PC/PC) cord insertions., Outcome Measures: Vascular numerical density (number of vascular profiles per unit villus stromal area) of intermediate villi (>80 μm diameter) and terminal villi (<80 μm)., Results: For twins with paracentral cord insertion, the vascular numerical density of intermediate villi was significantly higher for twins in a discordant PC/V relationship than for those in a concordant PC/PC relationship (P<0.05), thus replicating previous findings in superficial chorionic vessels. For terminal villi, in contrast, the vascular numerical density of twins with paracentral cords in a PC/V combination was significantly lower than of those in a PC/PC combination, and similar to that of their co-twins with velamentous cord insertion., Conclusions: Early placental angiogenesis in monochorionic twin gestations may be influenced by implantation and cord localization of the co-twin. The regulation of terminal villus angiogenesis appears to be dissociated from more proximal villus angiogenesis and independent of cord insertion of the co-twin., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Objective: The aims of this study were to develop a nomogram of umbilical cord diameter (UCD) for pathologic examination of the placenta, to identify the umbilical cord components responsible for variations in UCD, and to examine the relationship between UCD and other placental pathologic features and perinatal outcome., Study Design: We prospectively collected 497 umbilical cords between 18 and 41 weeks' gestation over a 1-year period. Fresh-tissue UCD were grouped according to gestational age and compared to sonographic and histological measurements. Associations between UCD percentile and placental pathologic findings or obstetrical outcomes were examined., Results: Mean UCD increased with gestational age until a plateau at 1.0 cm in the third trimester, a value that was 0.56 cm less than sonographic measurements prior to delivery and 0.17 cm greater than UCD measured histologically. Umbilical cord components varied with UCD percentile, with umbilical vessel area increased in thick cords (p < 0.001) and Wharton's jelly area reduced in thin cords (p = 0.002). Thin umbilical cords were associated with at least one pathologic histological placental finding (p = 0.02), low placental weight (p < 0.001), single umbilical artery (p = 0.02), marginal cord insertion (p = 0.01), and low infant birth weight (p < 0.001)., Conclusions: This study provides reference curves for post-delivery UCD from 18 to 41 weeks' gestation for use by perinatal pathologists. We show that increased UCD is a function of increased umbilical blood vessel volume and decreased UCD is a function of decreased Wharton's jelly volume. UCD shows a strong association with placental and infant birth weight., (Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.)

Sensitivity of chorionic plate arteries to angiotensin II (AngII) is greatest at the placental periphery. Angiotensin converting enzyme (ACE) is central to the synthesis of AngII and is present in the placental vasculature. We measured vascular ACE activity/mg protein at 8-9 sites between the cord insertion and the periphery in 12 term placentae from normotensive, vaginally-delivered women. ACE increased from insertion to the periphery (P = 0.015); median ACE for each placenta was positively correlated with placental weight (P < 0.05) and placental:birthweight ratio (P < 0.02). We speculate that this may be related to fetal programming since placental:birthweight ratio is related to long-term health., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Background: Non-central cord insertion has been associated with diminished chorionic vascular distribution in singleton placentas. The choriovascular correlates of peripheral cord insertion in diamniotic-monochorionic twin placentas remain undetermined., Aim: To study the association between type of cord insertion and choriovascular distribution of both twin territories in diamniotic-monochorionic twin placentas., Design: A prospective cohort of 138 monochorionic placentas was examined at Women and Infants Hospital between 2009 and early 2011. Thirty-five cases (25%), including disrupted placentas, placentas from higher order multiples and placentas from pregnancies complicated by twin-to-twin transfusion syndrome, were excluded. The correlation between cord insertion type and superficial choriovascular distribution was studied in the remaining 103 dye-injected diamniotic-monochorionic placentas. Cord insertion was categorized as paracentral, marginal or velamentous. The choriovascular distribution of each individual twin territory was assessed by analysis of number and density (number per surface area) of perforating chorionic arteries (PCA)., Results: In contrast with singleton placentas, there was no correlation between cord insertion type and a twin's own choriovascular distribution in diamniotic-monochorionic placentas. However, a strong correlation was found between the choriovascular distribution of one twin and the cord insertion type of the opposite twin. For a twin with paracentral or marginal cord insertion, the PCA density was significantly higher if the co-twin had a velamentous cord insertion than if the co-twin had a paracentral cord insertion (P < 0.001 and P < 0.05, respectively). Similarly, the PCA density of a twin with velamentous cord insertion tended to be higher if the co-twin had a velamentous, rather than paracentral cord insertion (P = 0.09)., Conclusions: This is the first study to suggest that in diamniotic-monochorionic twin gestations, the choriovascular architecture correlates with the cord insertion type of the co-twin. In general, velamentous cord insertion is associated with expanded choriovascular distribution in the opposite twin territory. Our observations may reflect novel manifestations of twin interdependence in monochorionic pregnancies., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Objective: The purpose of this study was to evaluate the impact of noncentral placental cord insertion on birthweight discordance in twins., Study Design: We performed a multicenter, prospective trial of twin pregnancies. Placental cord insertion was documented as central, marginal, or velamentous according to a defined protocol. Association of the placental cord insertion site with chorionicity, birthweight discordance, and growth restriction were assessed., Results: Eight hundred sixteen twin pairs were evaluated; 165 pairs were monochorionic, and 651 pairs were dichorionic. Monochorionic twins had higher rates of marginal (P = .0068) and velamentous (P < .0001) placental cord insertion. Noncentral placental cord insertion was more frequent in smaller twins of discordant pairs than control pairs (29.8% vs 19.1%; P = .004). Velamentous placental cord insertion in monochorionic twins was associated significantly with birthweight discordance (odds ratio, 3.5; 95% confidence interval, 1.3-9.4) and growth restriction (odds ratio, 4; 95% confidence interval, 1.1-14.3)., Conclusion: Noncentral placental cord insertion contributes to birthweight discordance in monochorionic twin pregnancies. Sonographic delineation of placental cord insertion may be of value in antenatal assessment of twin pregnancies., (Copyright © 2011 Mosby, Inc. All rights reserved.)

Background: Umbilical cords of fetuses in breech presentation differ in length and coiling from their cephalic counterparts and it might be hypothesised that these cord characteristics may in turn affect ECV outcome., Aim: To investigate the relation between umbilical cord characteristics and the outcome of external cephalic version (ECV)., Study Design: Prospective cohort study., Subjects: Women (>35 weeks gestation) with a singleton fetus in breech presentation, suitable for external cephalic version. Demographic, lifestyle and obstetrical parameters were assessed at intake. ECV success was based on cephalic presentation on ultrasound post-ECV. Umbilical cord length (UCL) and umbilical coiling index (UCI) were measured after birth., Outcome Measure: The relation between umbilical cord characteristics (cord length and coiling) and the success of external cephalic version., Results: ECV success rate was overall 79/146 (54%), for multiparas 37/46(80%) and for nulliparas 42/100 (42%). Multiple logistic regression showed that UCL (OR: 1.04, CI: 1.01-1.07), nulliparity (OR: 0.20, CI: 0.08-0.51), frank breech (OR: 0.37, 95% CI: 0.15-0.90), body mass index (OR: 0.85, CI: 0.76-0.95), placenta anterior (OR: 0.27, CI: 0.12-0.63) and birth weight (OR: 1.002, CI: 1.001-1.003) were all independently related to ECV success., Conclusions: Umbilical cord length is independently related to the outcome of ECV, whereas umbilical coiling index is not., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Objective: To determine the possible protective effects of Wharton's jelly (WJ) in umbilical cord and fetal growth by investigating the relationship between the amount of WJ and fetal birth weight., Materials and Methods: This study enrolled 299 women who delivered after an uneventful pregnancy. After separation of the placenta, a 5cm long section of umbilical cord was removed by scalpel. The weight of the cord section; the weight, volume, and density of its WJ; and the weight of the newborn and placenta were measured., Results: A significant positive correlation was found between WJ quantity, birth weight (p=0.002), and placental weight (p=0.003), whereas a significant negative correlation was observed for WJ density, fetal growth (p=0.035), and placental growth (p=0.002). WJ density was 1.63 ± 0.27g/mL. No significant correlation was found between the amount of WJ and weight gained during pregnancy (p=0.274) or maternal age (p=0.220)., Conclusion: As the amount of WJ increases, fetal weight increases. Accordingly, the amount of WJ might be a factor that influences fetal growth., (Copyright © 2011. Published by Elsevier B.V.)

Background: The position of the placental cord insertion, its shape and cord coiling are thought to be associated with perinatal outcome. This study derives indices describing the relationship of cord insertion to the placental centre, the shape of the placenta and cord coiling in placentas from unselected term pregnancies. Further, we investigate these indices in pregnancies affected by pre-eclampsia (PET), pregnancy induced hypertension (PIH), gestational diabetes mellitus (GDM) and delivery of a small for gestational age (SGA) baby., Design/methodology: Eight hundred and sixty one unselected women with singleton pregnancy delivering at 37-42 weeks were prospectively recruited to this study. Placental axes and their relationship with the cord insertion were measured using digital photography and proprietary software. From these, the cord centrality (distance of umbilical cord insertion from the centre) and placental eccentricity (deviation of the placental shape from circular) were derived. The cord coiling index (number of coils in the cord divided by the length of cord in cm) was also calculated from manual measurements., Results: The mean value of cord centrality index was 0.36 (SD = 0.21) and of placental eccentricity 0.49 (SD = 0.17). Left direction of umbilical cord coiling was more common than right (79% vs 16.4%) The mean cord coiling index was 0.20 (SD = 0.09) coils/cm. The indices were constant between 37 and 42 weeks and were no different in the non-affected population compared to women with pre-eclampsia (n = 17), PIH, (n = 27), GDM (n = 38) or delivery of an SGA baby (n = 54)., Conclusion: The cord centrality index that we derive suggests that the cord insertion is most commonly 'off centre', and eccentricity index that the placental shape is elliptical. Therefore, contrary to widely held belief, the cord does not normally insert centrally nor is the placenta normally round in shape. There is a preponderance of left sided coiling. There was no difference for any of the indices between the non-affected pregnancies and pregnancies affected by pre-eclampsia, PIH, GDM and SGA., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Goals: Fetal growth depends on placental growth; the fetoplacental weight ratio (FPR) is a common proxy for the balance between fetal and placental growth. Male and female infants are known to have differing vulnerabilities in fetal life, during parturition and in infancy. We hypothesized that these differences may be paralleled by differences in how birth weight (BW) and the fetoplacental weight ratio (FPR) are affected by changes in placental proportions., Materials and Methods: Placental proportion measures (disk shape, larger and smaller chorionic diameters, chorionic plate area calculated as the area of an ellipse with the 2 given diameters, disk thickness, cord eccentricity and cord length) were available for 24,601 participants in the Collaborative Perinatal Project delivered between >34 and <43 completed weeks. The variables were standardized and entered into multiple automated regression splines (MARS 2.0, Salford Systems, Vista CA) to identify nonlinearities in the relationships of placental growth measures to BW and FPR with results compared for male and female infants., Results: Changes in chorionic plate growth in female compared to male infants resulted in a greater change in BW and FPR. The positive effects of umbilical cord length on BW reversed at the mean umbilical cord length in females and at +0.08 SD in male infants., Conclusions: Female infants' BW and FPR are each more responsive to changes in placental chorionic plate growth dimensions than males; this may account for greater female resilience (and greater male vulnerability) to gestational stressors. The effect of umbilical cord length on FPR may be due to longer cords carrying greater fetal vascular resistance. Again male fetuses show a higher "threshold" to the negative effects of longer cords on FPR.

To study placental characteristics in relation to perinatal outcome in 150 pairs of monochorionic diamniotic (MCDA) twins. Between January 1998 and January 2007 150 pairs of MCDA twins were delivered in the University Medical Center, Utrecht, The Netherlands. Mortality, neonatal morbidity and birth weight discordancy were studied in relation to type of anastomoses, type and distance between cord insertions and placental sharing. From 14 weeks onwards, there were 45 (15.0%) perinatal deaths. We found no clear relationship between perinatal mortality and type of anastomoses, distance between cord insertions and placental sharing. Perinatal mortality was significantly increased in the presence of velamentous cord insertion (OR 3.65, 95% CI 1.83-7.28). Data concerning neonatal morbidity were similar. TTTS occurred predominantly in the presence of AV-anastomoses without compensating superficial AA-anastomoses (p=0.005) and occurred more frequently in the presence of velamentous cord insertion (OR 1.79, 95% CI 0.94-3.44). Twins with unequal shared placentas had significantly more often severe birth weight discordancy, although only in the presence of AA-anastomoses (OR 4.09, 95% CI 1.74-9.63). If AA-anastomoses were absent in the unequally shared placenta, there was no relation between severe birth weight discordancy and unequal sharing of the placenta (OR 1.06, 95% CI 0.08-13.52). In MCDA twins, placental characteristics determine perinatal outcome, occurrence of TTTS and fetal growth. Prenatal identification of these characteristics by ultrasound may alter counselling and intensity of pregnancy surveillance.

This study was designed to establish the morphological features of the placenta of the Martina Franca jenny. Ten placentas were harvested at the time of foal delivery and examined both for gross and histological characteristics. The following factors were determined: the total weight and volume of the placenta and its components, the surface area of the allantochorion, umbilical cord length and site of insertion, and the diameter of the umbilical cord vessels and vascular pattern type. The weight of the placenta was similar to previously reported for ponies, and represented 12% of foal birth weight. Umbilical cord length was similar to that in the horse but longer than in the pony, while cord weight was intermediate between the two. In a histological examination, numerous strong villi were observed at sites corresponding to the non-pregnant and pregnant horn and uterine body. No villi were detected in the area overlying the cervical star. Despite obvious similarities between the donkey and horse placenta, specific morphological features do exist, and are possibly related to the differences in length of gestation.

To elucidate the morphological differences between placentas from normal and cloned cattle pregnancies reaching term, the umbilical cord, placentomes and interplacentomal region of the fetal membranes were examined macroscopically as well as by light and scanning electron microscopy. In pregnancies established by somatic nucleus transfer (NT), the umbilical cord and fetal membranes were edematous. Placentomal fusion was common, resulting in increased size and a decreased number of placentomes. Extensive areas of the chorioallantoic membrane were devoid of placentomes. An increased number of functional or accessory microcotyledons (<1 cm) were present at the maternally oriented surface of fetal membranes. Extensive areas of extravasated maternal blood were present within the placentomes and in the interplacentomal region. The crypts on the caruncular surface were dilated and accommodated complexes of more than one primary villus, as opposed to a single villus in non-cloned placentae. Scanning electron microscopy of blood vessel casts revealed that there was also more than one stem artery per villous tree and that the ramification of the vessels failed to form dense complexes of capillary loops and sinusoidal dilations as in normal pregnancies. At the materno-fetal interface, however, the trophoblast and uterine epithelium had normal histology. In conclusion, the NT placentas had a range of pathomorphological changes; this was likely associated with the poor clinical outcome of NT pregnancies.

Several recent publications have focused on the association between the occurrence of twin-to-twin transfusion syndrome (TTTS) in diamniotic-monochorionic twins and the presence of a number of selected anatomic placental characteristics (distribution of vascular territory, cord insertion, type and number of inter-twin anastomoses). In contrast, the potential importance of the vascular distribution patterns of the individual twins remains to be elucidated. Based on its gross architectural distribution pattern, chorionic vasculature is traditionally described as disperse, magistral or mixed. The aim of this study was (1) to determine the relative prevalence of these vascular distribution patterns in monochorionic twin placentas, and (2) to correlate these patterns with the presence of TTTS and known anatomic placental features linked to TTTS. The placentas of 89 consecutive diamniotic-monochorionic twins (15 with TTTS, 74 without TTTS), examined at Women and Infants Hospital, were studied. Disperse vascular patterns were seen in 53% of twins, and magistral or mixed patterns in 47%. The prevalence of magistral/mixed vascular patterns was significantly higher in TTTS gestations than in non-TTTS gestations (60% versus 44%, P<0.05) and, in TTTS gestations, much higher in donor twins than in recipient twins (87% versus 33%, P<0.005). A strong association was found between the presence of magistral/mixed patterns and marginal/velamentous cord insertion, low number of inter-twin anastomoses, and uneven distribution of the vascular territories. These findings suggest that the magistral/mixed vascular distribution pattern may represent an important placental architectural feature contributing to the complex pathophysiology of TTTS.

Background: Umbilical vein constriction at the fetal abdominal inlet is a common finding after week 13, when the period of umbilical herniation is brought to an end., Aims: To test the hypothesis that a constricting umbilical ring within physiological ranges affects fetal hemodynamics by either pooling blood in the placenta or restricting nutrient transfer to the fetus and thus shift the birthweight/placental weight (BW/PW) ratio. A constriction could also cause pressure changes and elongation of the cord and possibly be a disadvantage during labour., Study Design: Cross-sectional., Subjects: 359 Low-risk singleton pregnancies at 13-40 weeks of gestation., Outcome Measures: Standard deviation score (z-score) and regression analysis were used to determine the effect of umbilical vein constriction (expressed by increased blood velocity) on birthweight/placental weight ratio (BW/PW), cord length, Apgar score and emergency delivery due to fetal distress., Results: Umbilical venous constriction had a mild but significant effect on BW/PW in male (p=0.018) but not in female fetuses. Increased constriction was also associated with increased length of the cord but only in female fetuses (p=0.019). Cord length was positively related to birthweight and placental weight, but an increased length of the cord was also associated with decreasing BW/PW ratio for the male fetuses only (p=0.044). Increasing degree of venous constriction was associated with Apgar score < or =7 at 1 (p=0.009) but not at 5 min after birth and was not associated with emergency delivery., Conclusion: Physiological umbilical venous constriction exerts a mild but significant gender-specific hemodynamic impact on intrauterine development.

Cystic periventricular leukomalacia (cPVL), the principal ischemic brain injury in premature infants, is characterized by necrosis of the white matter in the periventricular region and the major neuropathology for spastic motor deficits in cerebral palsy or epilepsy. Recent reports strongly suggest that the brain injury associated with cPVL may have already occurred in utero. In this study we searched retrospectively for possible clinical situations related to cPVL to facilitate assessment of optimal management. A total of 201 babies born at gestational ages from 24 to 33 weeks were entered into the study (1992-1997) and examined for involvement of 18 factors in cPVL retrospectively. And psychomotor development was examined at least until 18 months of corrected age. Among 201 premature babies 35 cases were diagnosed as cPVL later developed spastic diplegia. There are 23 cases of preeclampsia, no infant suffering from cPVL. In the univariate analysis, exposure to antenatal indomethacin, cord length > or =40 cm, and a low Apgar score were significantly associated with a 2-3 risk increased of cPVL occurrence, while antenatal magnesium sulfate reduced the risk. Chorioamnionitis was positively correlated with the risk, but did not reach statistical significance. In the multivariate analysis we found the statistical significance in exposure to antenatal indomethacin, a low Apgar score, and antenatal magnesium sulfate. Our results suggested that preeclampsia and antenatal exposure of magnesium sulfate reduced the risk while antenatal exposure of indomethacin and low Apgar score associated with the occurrence of cPVL. These findings support a growing consensus that cPVL is often the result of maternal and fetal factors as well as antenatal treatment.

Objective: The length of the umbilical cord varies widely from one pregnancy to another. Although its average length is 50 cm, this measurement could vary from as little as 20 cm to more than one metre. The purpose of our study was to evaluate, in utero, the length of the umbilical cord during the third trimester of pregnancy knowing the propagation velocity of the pressure wave along the cord., Material and Methods: The computation of the apparent length requires two ultrasound transducers, one situated at the aortic fetal arch, the other at the placental extremity of the umbilical artery. Knowing the velocity of the pressure wave (v), as well as the time interval between the systolic peak of two waves (delta t), we can deduce the length of the umbilical cord (delta t x v)., Results: The comparison between the calculated length and the actual length measured shows a significant correlation with a probability of 1%., Conclusion: The knowledge of the length of the umbilical cord is quite useful in the physio-pathological interpretation of the placental resistance index. It is also of interest, before the delivery, to know the length of the cord in order to foresee dystocy and how it relates cord which is either too short or too long.

Objective: The null hypothesis is that fetuses with noncoiled umbilical cords diagnosed in the antepartum period will have outcomes no different from those with normally coiled cords., Study Design: We prospectively gathered data from Jan. 1 through May 18, 1992, from all fetuses undergoing routine ultrasonographic evaluation. The outcomes of fetuses noted to have noncoiled umbilical cords were compared with those of a control group of fetuses with normally coiled cords. The control group consisted of those subjects undergoing ultrasonography during the study period who were ultimately transferred to our perinatal practice for the remainder of the pregnancy (i.e., the highest-risk patients). Two outcome parameters were selected for comparison: fetal anomalies and fetal death., Results: Six hundred eighty-seven consecutive ultrasonographic examinations were performed. Twenty-five subjects (3.7%) had noncoiled umbilical cords identified ultrasonographically (mean gestational age at diagnosis 20.3 +/- 3.5 [SD] weeks). The control group had 197 subjects. The combined incidence of fetal anomalies or death in the noncoiled group (16%) was significantly greater (p < or = 0.05, relative risk 4.6 [95% confidence interval 1.41 to 14.15]) than that of the control group (3.5%). The noncoiled group had two fetal deaths (8%), whereas two deaths (1%) occurred among controls (p < or = 0.05, relative risk 8 [95% confidence interval 1.16 to 50]). Two (8%) fetal anomalies (anencephaly, prune-belly syndrome) occurred in the noncoiled group, whereas the controls (n = 197) had five fetuses (2.5%) with anomalies (not significant)., Conclusion: The antepartum identification of noncoiled umbilical cords appears to be a risk factor for suboptimal pregnancy outcome.

The distances between the xyphoid appendix and the insertion point of the umbilical cord (XU) and between the xyphoid appendix and upper edge of the pubic symphysis (XP) were measured in 201 newborn infants. The mean ratio XU/XP was 0.62 (S.D. 0.044) with no differences between sexes nor correlations with weight or length. Ratios lying between 0.53 and 0.71 can be considered as within the normal range.

Six hundred and sixty-one consecutive umbilical cords of babies at term in an African obstetric population were studied. The mean cord length was 58.4 +/- 12.02 cm. The pattern of frequency distribution of cord length in this study conforms to previous findings from other racial groups, establishing the fact that cord length and its variability are not racially determined. There is a significant correlation between the cord length and weights of the fetus and placenta but not with the mother's parity.

The Poiseuille equation of fluid flow suggests that umbilical cord length and cord blood viscosity may affect resistance to flow and thus affect the systolic/diastolic ratio. In this prospective study of 40 uncomplicated term pregnancies, we sought to define the relationship of umbilical cord length and cord blood hematocrit level (as an index of viscosity) to the umbilical artery systolic/diastolic ratio. To focus on these factors, we minimized known sources of systolic/diastolic ratio variability and controlled for fetal heart rate. Linear regression revealed that fetal heart rate contributed 18% of the systolic/diastolic ratio variability. Conversely, umbilical cord length and cord blood hematocrit level were not related to umbilical artery systolic/diastolic ratio. We conclude that normal variations in cord blood hematocrit level and umbilical cord length do not significantly affect systolic/diastolic ratio.

Umbilical cord length was measured in 9620 male and 9068 female infants and related to gestational age in order to construct a growth chart for umbilical cords. In addition to providing a standard for the US white population, these growth charts illustrate that umbilical cord length is widely divergent at the same gestational age, males have longer cords than females (P less than 0.0001), and umbilical cord growth continues throughout the third trimester.

The purpose of this study was to evaluate the origin, direction, and relevance of the umbilical cord twist. We initially hypothesized that the direction of the helix or twist of the human umbilical cord at birth correlated with the eventual handedness of the child. Among 2801 singleton placentas in this study, only 5% had no twist, and the left twist outnumbered the right twist by 7 to 1, a ratio that is strikingly similar to the predominance of right-handed persons to non-right-handed persons in the general population. Forty-five 3- and 4-year-old children with previously documented cord twists were evaluated with respect to hand preference and performance. The direction of the cord twist was independent of the handedness of the child as well as the mother. We have documented an increased incidence of absent twist and right twist in association with single umbilical artery, suggesting that the impetus for the cord twist is independent on hemodynamic forces in the umbilical cord itself. We further document an increased incidence of absent twist among intrauterine fetal deaths and twins, suggesting that decreased fetal movement can impede the forces leading to normal twisting of the umbilical cord. Absence of cord twist may be associated with adverse prognosis.

Umbilical cord length may be a function of fetal movement. Agents that cause decreased fetal movement may cause short umbilical cords. This investigation examined the effect of the beta-blocker atenolol on umbilical cord length in rabbits. Fetuses of rabbits treated with atenolol had significantly shorter cords than control animals (p less than or equal to 0.0005). Since short cords are associated with problems in labor, low Apgar scores, and abruption, we recommend careful surveillance of mothers and fetuses who are given beta-blocking agents in the first 30 weeks of pregnancy.

A current hypothesis on the linear growth of the umbilical cord states that cord length is a function of fetal intrauterine motor activity. If there is some type of intrauterine constraint, the tensile forces on the cord will be diminished, and cord length at term will be shorter than if no such constraint is present. One would expect that the voluntary movements of twins would develop under a constraint and that they would have less free space to move compared with single fetuses. If this hypothesis is valid, cord lengths of twins at term would be shorter than those of single pregnancy infants. We measured the cord lengths of 118 infants in 59 twin births and compared them with cord lengths in 9601 single pregnancies. We found that on the average, the umbilical cord length of the twins was 7.90 cm shorter than that of single pregnancy infants.

The umbilical cord is an amniotic structure histologically resembling amnion lining the basal plate and reflected chorion. Prostaglandin E2 is secreted by amnion and is present in amniotic fluid. This study measured prostaglandin E2 production by amnion from all three locations to determine the relative contributions of prostaglandin E2 to amniotic fluid at term. Total surface areas and weights of umbilical cord, basal placental plate, and reflected chorionic amnion were measured in afterbirths from 20 normal patients delivered at term by elective repeat cesarean section before the onset of labor or vaginally after spontaneous onset of labor. Subsequently, 2 cm lengths of umbilical cord and 8 cm2 disks of basal placental plate and reflected chorionic amnion were incubated in perfusion chambers, and prostaglandin E2 production was measured by radioimmunoassay. Umbilical cord accounted for the least surface area (16% to 17%) but greatest tissue mass (75% to 76%). Both basal placental plate and reflected chorionic amnion increased prostaglandin E2 production 2.3-fold and 4.1-fold, respectively, after labor versus before labor, whereas umbilical cord prostaglandin E2 output was unchanged. However, umbilical cord accounted for 66% and 44% of the total prostaglandin E2 output before labor (697 +/- 169 ng/hr) versus (1201 +/- 380 ng/hr) after labor. Thus, of the three amniotic locations, umbilical cord represents the principal site of prostaglandin E2 production within the gestational sac.

Our experience in 65 patients using a "fetoscope" and local anesthesia prior to saline abortion is described. Visualization of the intrauterine contents improved with experience, was optimum at 16 to 18 weeks' gestation, and was superior to the quality of photographic records. Four fetal skin biopsies and 6 amnion biopsies were done. Six blood samples were taken from the fetal surface of the placenta. The limitations of this instrument are described. No significant complications have occurred. Current and probable future indications for fetoscopy are reviewed. Until both the safety of the procedure is proved and problems of visualization due to limitation of visual field are solved, extreme caution is urged in the employment of this instrument in genetic high-risk pregnancy.

Fifty umbilical cords were prepared and examined and their venous perfusion pressures measured with and without a true knot in the cord. Contrary to information in the literature, a loose umbilical cord knot did not affect the venous perfusion pressure. With a tightened knot, the smaller the umbilical cord diameter, the greater was the pressure required to perfuse past the knot. The umbilical vessels, protected by the myxomatous structure of the Wharton's jelly, were rarely completely occluded. These findings correlate clinically with the relatively high incidence yet low fetal mortality rate actually due to a true knot in the umbilical cord.

Expectant management of prolonged pregnancy is predicated on reassuring biophysical testing. However, even the combination of a reactive nonstress test and normal amniotic fluid volume may not prevent subsequent morbidity. To test the hypothesis that diminished cord Wharton's jelly incurs risk of peripartum cord compression in addition to decreased amniotic fluid, 68 patients with confirmed gestational age greater than or equal to 41 weeks were evaluated prospectively with semiweekly nonstress tests and weekly ultrasound examinations. Amniotic fluid volume was assessed, and umbilical cord diameter was measured and then correlated with the quantity of Wharton's jelly at delivery, determined by cord circumference. A significant correlation between cord circumference and umbilical cord diameter was observed, even in those patients with decreased amniotic fluid volume. Either an amniotic fluid volume less than 3.8 cm or an umbilical cord diameter less than 1.6 cm was associated with significant cord compression patterns. Peripartum morbidity was greatest in the presence of a smaller cord and decreased fluid, suggesting a synergism between these two factors for the risk of cord compression in prolonged pregnancy.

Bleeding from the site of cordocentesis can be detected by ultrasound examination, but significant hemorrhage into the amniotic fluid rarely occurs. To evaluate the relative contribution of amniotic fluid thromboplastins and the quantity of Wharton's jelly in facilitating coagulation at the puncture site, amniotic fluid samples and umbilical cord segments were obtained at cesarean section from 20 patients. After puncture of the umbilical vein, bleeding times were measured in amniotic fluid and 0.9% sodium chloride. The quantity of Wharton's jelly was assessed by measuring umbilical cord circumference. Mean bleeding times were significantly shorter in amniotic fluid compared with saline solution, but there was no consistent relationship between bleeding times and umbilical cord circumference. We conclude that properties of amniotic fluid facilitate coagulation at the site of umbilical vein puncture.

The present study is based on two previously stated theories: (1) that the umbilical cord length is influenced by fetal motor activity and (2) that the breech presentation is associated with low fetal motor activity. From this one would expect the mean cord length to be shorter in breech presentations as compared with vertex. This was indeed found to be the case. An already known difference between the sexes regarding cord length was also confirmed, and a difference in male:female ratio in the two presentations is shown. The results of the study thus seem to support the two stated theories.

We examined the gross and microscopic anatomy of placental tissues and umbilical cords from six species representing the three living families of the Suina. These species included, of the Suidae, the wart hog (Phacochoerus aethiopicus), the giant forest hog (Hylochoerus meinertzhageni), the domestic pig (Sus scrofa), and the banded pig of Malaysia (Sus scrofa vittatus); of the Tayassuidae, the white-lipped peccary (Tayassu pecari); of the Hippopotamidae, the hippopotamus (Hippopotamus amphibius) and the pigmy hippopotamus (Choeropsis liberiensis). All these species have a diffuse epitheliochorial placenta. The chorion is folded, and has on its surface rows of shallow ripples or villi, interrupted by round, oval or irregularly shaped areolae. Placental capillaries indent the epithelial layer covering the tops and sides of the interareolar villi, but not the columnar cell layer lying in the troughs between these villi or covering the areolae. Cuboidal cells cover the crests of the villi in the Suidae and Hippopotamidae, whereas in the Tayassuidae the epithelium is syncytial in appearance. The similarities in placental structure between the six species are more apparent than the differences. Suidae and Tayassuidae have smooth umbilical cords containing two arteries and one vein; those of the Hippopotamidae are pustule-encrusted and contain two arteries and two veins.