Search

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: 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.)

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.)

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.)

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.)

Unlabelled: Twin pregnancies are regarded as high risk pregnancies. It results from the possibility of occurrence of numerous complications both like the ones in singleton pregnancies and those characteristic for multiple pregnancy only. The complication occurring exclusively in multiple pregnancies is discordant intrauterine growth of the fetuses., The Aim: a response to the question if there a relationship between the type of afterbirth and twin birth weight discordance., Material and Methods: Material of the research consisted of 186 afterbirths derived from successful twin pregnancies. In the study the following were taken into consideration: evaluation of placenta/placentas types (mono- or dichorionic), place of umbilical cords insertion, and differences concerning birth weight of newborns., Results: The birth weight discordance of less than 10% (l0) in the twins was noted in 52.7% of pregnancies (n=98), discordance of 10-20% (II degree) was observed in 30.1% (n=56), and over 20% (III degree) in 17.2% (n=32). The birth weight discordance of the third degree was observed significantly more often in dichorionic diamniotic pregnancies with fused placentas. The discordance of third degree (>20%) occurred in 38.2% of female-male pairs, in 35.7% of female-female ones and in 24.3% of male-male pairs. In case of coexistence of both normal umbilical cord insertions the birth weight discordance of third degree occurred in 17.8% of pregnancies, in case of co-occurrence of the abnormal insertion with the normal one--in 21.8% of cases, and in case of the two abnormal insertions--in 10.5%. No statistically significant differences were found., Conclusions: There is a relationship between the type of afterbirth and birth weight in twins. The largest birth weight discordance between fetuses occurs in the following cases: in dichorionic pregnancies with fused placental discs, in case of co-existence of abnormal and normal umbilical cord insertions and in female-male pair of twins.

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.

Fetal growth depends in part on placental growth. The authors tested placental measures derived from digital images for reliability and to evaluate their association with birth weight and gestational age. A total of 628 women recruited into the Pregnancy, Infection, and Nutrition Study, a prospective cohort study of preterm birth in central North Carolina between 2002 and 2004, delivered singleton liveborn infants after 24 completed weeks' gestation. Novel chorionic plate morphometric parameters captured off digital images of the gross placenta were analyzed as estimators of gestational age and birth weight. Without acknowledgment to placental weight, digitally obtained lateral chorionic plate growth measures accounted for 17 percent of gestational age variance and 35 percent of birth weight variance, overall. Chorionic plate measures accounted for 10 percent of birth weight variance beyond that accounted for by placental weight alone. Among preterm births, 34 percent of gestational age variance and 63 percent of birth weight variance were accounted for by lateral chorionic plate growth measures. Intraclass correlation coefficients for the novel digital measures ranged from 0.96 to 0.98. Reliable digital measures of lateral chorionic plate growth estimate birth weight variance more strongly than gestational age, project variance that is not accounted for by placental weight, and project these outcomes to a greater degree in preterm births than at term.

Several characteristics of newborns were investigated in our population from northwestern Greece, for the first time during the last 30 years, providing useful data. The study included 5,278 pregnant women who delivered from 1992-1996, and the following parameters have been studied: (1) age of pregnancy at the parturition, (2) weight of newborn, (3) weight of placenta, (4) age of the pregnant woman, and (5) length of the umbilical cord, all five in relation with parity. Statistically significant relationships were found between: (1) age of the pregnant woman and the parity (but not between paras-2 and paras-3), (2) weight of the newborns between primiparas, paras-3, and paras-4 as also paras-2 and paras-4, (3) length of the umbilical cord between primiparas and paras-3 and paras-4. No significant relationship was found between placenta weight and parity, nor between gestational age at the parturition and parity. The study gives these features for the first time, to our best knowledge, of the birth characteristics of a certain and very homogeneous population of northwestern Greece, and these useful data could be the basis for future studies and comparisons with other populations.

We investigated whether variations in mode of attachment of umbilical cords and vessels coincided with differences in maternal haemoglobin genotype and neonatal factors or placental micro-volumetric composition. The incidence of placentae with marginally inserted cords, or those in which umbilical vessels separated prior to insertion, was not statistically different in samples from sickle cell patients having haemoglobin-SS and haemoglobin-SC genotypes, as compared with haemoglobin-AA controls. Results obtained from analysis of variance (ANOVA) suggest that the mode of insertion (status) of umbilical vessels may have clinical significance, because it produced differences in the main effects associated with neonatal gestational age, placental weight, and placental index. Point counting stereology was employed to estimate the microscopic compartment volumes of placentae prior to an assessment of statistical association between the data obtained and the status of umbilical vessels and maternal haemoglobin genotype. Furcate placentae (with separated umbilical vessels) had statistically greater than normal volumes of villi, villous trophoblast, and syncytial knots. We deduce that furcate placentae are prone to early delivery, because they are heavier, having more voluminous villi with more trophoblast and syncytial knots than controls.

The site of the insertion of the umbilical cord into the placenta was determined in 940 consecutive term infants. No relation was found between birth weight and whether the cord was inserted centrally, eccentrically or marginally.