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In the management of shoulder dystocia, it is often recommended to start with external maneuvers, such as the McRoberts maneuver and suprapubic pressure, followed by internal maneuvers including rotation and posterior arm delivery. However, this sequence is not based on scientific evidence of its success rates, the technical simplicity, or the related complication rates. Hence, this review critically evaluates the success rate, technique, and safety of different maneuvers. Retrospective reviews showed that posterior arm delivery has consistently higher success rates (86.1%) than rotational methods (62.4%) and external maneuvers (56.0%). McRoberts maneuver was thought to be a simple method, however, its mechanism is not clear. Furthermore, McRoberts position still requires subsequent traction on the fetal neck, which presents a risk for brachial plexus injury. The 2 internal maneuvers have anatomic rationales with the aim of rotating the shoulders to the wider oblique pelvic dimension or reducing the shoulder width. The techniques are not more sophisticated and requires the accoucher to insert the correct hand (according to fetal face direction) through the more spacious sacro-posterior region and deep enough to reach the fetal chest or posterior forearm. The performance of rotation and posterior arm delivery can also be integrated and performed using the same hand. Retrospective studies may give a biased view that the internal maneuvers are riskier. First, a less severely impacted shoulder dystocia is more likely to have been managed by external maneuvers, subjecting more difficult cases to internal maneuvers. Second, neonatal injuries were not necessarily caused by the internal maneuvers that led to delivery but could have been caused by the preceding unsuccessful external maneuvers. The procedural safety is not primarily related to the nature of the maneuvers, but to how properly these maneuvers are performed. When all these maneuvers have failed, it is important to consider the reasons for failure otherwise repetition of the maneuver cycle is just a random trial and error. If the posterior axilla is just above the pelvic outlet and reachable, posterior axilla traction using either the accoucher fingers or a sling is a feasible alternative. Its mechanism is not just outward traction but also rotation of the shoulders to the wider oblique pelvic dimension. If the posterior axilla is at a higher sacral level, a sling may be formed with the assistance of a long right-angle forceps, otherwise, more invasive methods such as Zavanelli maneuver, abdominal rescue, or symphysiotomy are the last resorts. [ABSTRACT FROM AUTHOR]

Umbilical cord prolapse is an unpredictable obstetrical emergency with an incidence ranging from 1 to 6 per 1000 pregnancies. It is associated with high perinatal mortality, ranging from 23% to 27% in low-income countries to 6% to 10% in high-income countries. In this review, we specifically addressed 3 issues. First, its definition is not consistent in the current literature, and "occult cord prolapse" is a misnomer because the cord is still above the cervix. We proposed that cord prolapse, cord presentation, and compound cord presentation should be classified according to the positional relationship among the cord, the fetal presenting part, and the cervix. All of them may occur with either ruptured or intact membranes. The fetal risk is highest in cord prolapse, followed by cord presentation, and lastly by compound cord presentation, which replaces the misnomer "occult cord prolapse." Second, the mainstay of treatment of cord prolapse is urgent delivery, which means cesarean delivery in most cases, unless vaginal delivery is imminent. The urgency depends on the fetal heart rate pattern, which can be bradycardia, recurrent decelerations, or normal. It is most urgent in cases with bradycardia, because a recent study showed that cord arterial pH declines significantly with the bradycardia-to-delivery interval at a rate of 0.009 per minute (95% confident interval, 0.0003-0.0180), and this may indicate an irreversible pathology such as vasospasm or persistent cord compression. However, cord arterial pH does not correlate with either deceleration-to-delivery interval or decision-to-delivery interval, indicating that intermittent cord compression causing decelerations is reversible and less risk. Third, while cesarean delivery is being arranged, different maneuvers should be adopted to relieve cord compression by elevating the fetal presenting part and to prevent further cord prolapse beyond the vagina. A recent study showed that the knee-chest position provides the greatest elevation effect, followed by filling of the maternal urinary bladder with 500 mL of fluid, and then the Trendelenburg position (15°) and other maneuvers. However, each maneuver has its own advantages and limitations; thus, they should be applied wisely and with great caution, depending on the actual clinical situation. Therefore, we have proposed an algorithm to guide this acute management. [ABSTRACT FROM AUTHOR]

Accurate diagnosis of chorioamnionicity in multiple pregnancies is the key to appropriate clinical management of multiple gestation. Although prenatal ultrasound assessment of chorioamnionicity is well established and highly accurate if performed in early pregnancy, exceptions and artifacts arise from anatomic variations in multiple pregnancies and unusual sonographic features do exist. We have summarized our own experiences and reports from the literature on these pitfalls as follows: (1) discordant fetal sex in monochorionic pregnancies due to sex chromosome abnormalities, genital malformation in 1 fetus, or dizygotic twins forming a monochorionic placenta; (2) separate placental masses in monochorionic pregnancies due to bipartite placenta; (3) false-negative and false-positive λ sign can arise for various reasons, and in partial monochorionic/dichorionic placentas both T and λ sign may co-exist; (4) intrauterine synechia appearing as a thick and echogenic intrauterine septum may lead to erroneous diagnosis of dichorionic twins; and (5) errors in ascertaining amnionicity by the visualization of thin intertwin amniotic membranes and the number of yolk sacs. The ultrasound techniques to reduce inaccuracy in prenatal determination of chorioamnionicity and the use of single nucleotide polymorphisms based on noninvasive prenatal test to determine zygosity are also reviewed. [ABSTRACT FROM AUTHOR]

Background: Immunomodulation is observed in human parturition. However, data from longitudinal studies for the prelabor phase and the active phase of labor are lacking, and no study had compared the immune responses during labor between nulliparous and multiparous women.Objective: This study aimed to investigate the temporal changes of immune biomarkers in maternal blood from the prelabor phase to the latent and active phases of labor and to compare the dynamic changes between nulliparous and multiparous women.Study Design: A prospective case-control study was conducted on women who had induction of labor at term followed by vaginal delivery. Maternal blood was serially collected at 3 consecutive time points: (1) before the onset of labor, (2) during the latent phase of labor, and (3) during the active phase of labor. Peripheral immune cells were measured by 4-color flow cytometry, and the plasma concentrations of cytokines and chemokines were measured by cytometric bead arrays. A longitudinal comparison was made to assess the dynamic changes in inflammatory parameters over 3 time points in nulliparous and multiparous women, respectively, and a cross-sectional comparison was made between nulliparous and multiparous women.Results: A total of 40 women, including 20 nulliparous and 20 multiparous, were included in the study. Prelabor circulating levels of macrophage inflammatory protein-1β, monokine induced by gamma interferon, and interferon gamma-induced protein-10 were higher in multiparous women than in nulliparous women. In the latent phase of labor, the innate immune system in both groups responded with increases in neutrophils and interleukin 6, and the nulliparous women showed a more pronounced response. During the active phase of labor, such innate immune response continued with both groups, with additional increases in natural killer cells, monocyte chemoattractant protein-1, interleukin 8, and interleukin 10. Conversely, the adaptive immune system in nulliparous women showed a reduction in both cytotoxic and helper T cells, whereas the adaptive immune system in multiparous women only had a reduction in helper T cells, showing a smaller reduction.Conclusion: Innate and adaptive immune responses partake in immunomodulation during human parturition. Nulliparous and multiparous women showed different responses in their blood levels of immune cells and biomarkers during the different phases of labor. [ABSTRACT FROM AUTHOR]

Background: First-trimester cervical length for the prediction of spontaneous preterm delivery remains controversial. A better method for the measurement of the first-trimester cervical length and additional cervical ultrasound parameters for the identification of women at high risk for spontaneous preterm delivery are needed.Objective: This study aimed to compare the predictive value of cervical length measured by 2 different methods in the first trimester of pregnancy to predict spontaneous preterm delivery and to explore the potential value of first-trimester cervical shear-wave elastography for the prediction of spontaneous preterm delivery.Study Design: This was a prospective study in unselected singleton pregnancies at 11+0 to 13+6 weeks' gestation. Cervical length was measured by the following 2 methods in the base-cohort population: (1) a linear distance between the 2 ends of the glandular area around the endocervical canal (single-line method: cervical length-s) and (2) a sum of the linear distance from the internal os to the greatest cervical curvature and the linear distance from this point to the external os (2-line method: cervical length-t). In a substudy, cervical shear-wave elastography scores for 9 regions of interest (inner, middle, and external parts of anterior lip, endocervical canal, and posterior lip) in midsagittal plane were also obtained by transvaginal ultrasonography. The screening performance of the first-trimester cervical length measured by the 2 different methods for the prediction of spontaneous preterm delivery was assessed by receiver operating characteristics curve analysis. The areas under the curves were compared using a DeLong test. The predictive performance of a soft cervix (mean elastography scores with multiple of median <5th, 10th, 15th, 20th, and 25th percentile) for spontaneous preterm delivery was also determined.Results: Among a total of 2316 included pregnancies, spontaneous delivery at <37 and <34 weeks' gestation occurred in 111 cases (4.8%) and 20 cases (0.9%), respectively. In the total study population, when compared with the term delivery group, the median cervical length-t was shorter in women with spontaneous delivery at <34 weeks' gestation (36.9 mm vs 35.1 mm; P=.015), but there was no clear correlation for cervical length-s. Receiver operating characteristics curves demonstrated that cervical length-t achieved better performance in predicting spontaneous delivery at <34 weeks' gestation (area under the curve, 0.658 vs 0.573; P<.01) than cervical length-s. The best combined model to predict spontaneous delivery at <34 weeks' gestation was provided by cervical length-t and history of preterm delivery (area under the curve, 0.692). In the substudy, a soft cervix with a mean elastography scores multiple of median <10th percentile had a relative risk of 7.8 (95% confidence interval, 2.1-28.6) for spontaneous delivery at <34 weeks' gestation; the detection rate was 44.4% at a false-positive rate of 9.0%.Conclusion: The 2-line approach provides a better estimate of the actual first-trimester cervical length and achieves better performance as a screening tool for spontaneous preterm delivery at <34 weeks' gestation than the conventional measurement. A soft cervix as determined by shear-wave elastograpthy in the first trimester is associated with an increased risk for subsequent spontaneous preterm delivery. [ABSTRACT FROM AUTHOR]

Background: The underlying pathomechanism in placenta-related selective fetal growth restriction in monochorionic diamniotic twin pregnancy is not known.Objective: This study aimed to investigate any differences in placental transcriptomic profile between the selectively growth-restricted twins and the normally grown cotwins in monochorionic diamniotic twin pregnancies.Study Design: This was a prospective study of monochorionic diamniotic twin pregnancies complicated by selective fetal growth restriction. Placental biopsy specimens were obtained from the subjects in the delivery suite. The placental transcriptome of the selectively growth-restricted twin was compared with that of the normally grown cotwin. This study was divided into 2 stages: (1) gene discovery phase in which placental tissues from 5 monochorionic diamniotic twin pregnancies complicated by selective fetal growth restriction plus 2 control twin pregnancies underwent transcriptome profiling, and transcriptome profiling was carried out using whole-genome RNA sequencing; and (2) validation phase in which placental tissues from 13 monochorionic diamniotic twin pregnancies with selective fetal growth restriction underwent RNA and protein validation. RNA and protein expression levels of candidate genes were determined using quantitative real-time polymerase chain reaction and immunohistochemistry staining.Results: A total of 1429 transcripts were differentially expressed in the placentae of selectively growth-restricted twin pairs, where 610 were up-regulated and 819 were down-regulated. Endoplasmic reticulum lectin and mannose 6-phosphate receptor were consistently differentially up-regulated in all placentae of selectively growth-restricted twins. Quantitative real-time polymerase chain reaction and immunohistochemistry staining were used to validate the results (P<.05).Conclusion: The expression of endoplasmic reticulum lectin and mannose 6-phosphate receptor, which are important for angiogenesis and fetal growth, was significantly increased in the placentae of selectively growth-restricted twin of a monochorionic twin pair. [ABSTRACT FROM AUTHOR]

Background: Placenta previa remains one of the major causes of massive postpartum hemorrhage and maternal mortality worldwide.Objective: To determine whether internal iliac artery balloon occlusion during cesarean delivery for placenta previa could reduce postpartum hemorrhage and other maternal complications.Study Design: This was a prospective randomized controlled trial conducted at a tertiary university obstetric unit in Hong Kong. Pregnant women who were diagnosed to have placenta previa at 34 weeks (defined as lower placenta edge within 2 cm from the internal os) and required cesarean delivery were invited to participate. Eligible pregnant women were randomized into internal iliac artery balloon occlusion (Occlusion) group or standard management (Control) group. Those randomized to the Occlusion group had internal iliac artery balloon catheter placement performed before cesarean delivery and then balloon inflation after delivery of the baby. The primary outcome was the reduction of postpartum hemorrhage in those with internal iliac artery balloon occlusion. Secondary outcome measures included hemoglobin drop after delivery; amount of blood product transfusion; incidence of hysterectomy; maternal complications including renal failure, ischemic liver, disseminated intravascular coagulation, and adult respiratory distress syndrome; length of stay in hospital; admission to intensive care unit; and maternal death.Results: Between May 2016 and September 2018, 40 women were randomized (20 in each group). Demographic and obstetric characteristics were similar between the 2 groups. In the Occlusion group, 3 women did not receive the scheduled procedure, as it was preceded by antepartum hemorrhage that required emergency cesarean delivery, and 1 woman had repeated scan at 36 weeks showing the placental edge was slightly more than 2 cm from the internal os. Intention-to-treat analysis found no significant differences between the Occlusion and the Control groups regarding to the median intraoperative blood loss (1451 [1024-2388] mL vs 1454 [888-2300] mL; P = .945), the median length of surgery (49 [30-62] min vs 37 [30-51] min; P = .204), or the need for blood transfusion during operation (57.9% vs 50.0%; P = .621). None of the patients had rebleeding after operation, complication related to internal iliac artery procedure, or any other maternal complications. Reanalyzing the data using on-treatment approach showed the same results.Conclusion: The use of prophylactic internal iliac artery balloon occlusion in placenta previa patients undergoing cesarean delivery did not reduce postpartum hemorrhage or have any effect on maternal or neonatal morbidity. [ABSTRACT FROM AUTHOR]

Background: The administration of aspirin <16 weeks gestation to women who are at high risk for preeclampsia has been shown to reduce the rate of preterm preeclampsia by 65%. The traditional approach to identify such women who are at risk is based on risk factors from maternal characteristics, obstetrics, and medical history as recommended by the American College of Obstetricians and Gynecologists and the National Institute for Health and Care Excellence. An alternative approach to screening for preeclampsia has been developed by the Fetal Medicine Foundation. This approach allows the estimation of patient-specific risks of preeclampsia that requires delivery before a specified gestational age with the use of Bayes theorem-based model.Objective: The purpose of this study was to examine the diagnostic accuracy of the Fetal Medicine Foundation Bayes theorem-based model, the American College of Obstetricians and Gynecologists, and the National Institute for Health and Care Excellence recommendations for the prediction of preterm preeclampsia at 11-13+6 weeks gestation in a large Asian population STUDY DESIGN: This was a prospective, nonintervention, multicenter study in 10,935 singleton pregnancies at 11-13+6 weeks gestation in 11 recruiting centers across 7 regions in Asia between December 2016 and June 2018. Maternal characteristics and medical, obstetric, and drug history were recorded. Mean arterial pressure and uterine artery pulsatility indices were measured according to standardized protocols. Maternal serum placental growth factor concentrations were measured by automated analyzers. The measured values of mean arterial pressure, uterine artery pulsatility index, and placental growth factor were converted into multiples of the median. The Fetal Medicine Foundation Bayes theorem-based model was used for the calculation of patient-specific risk of preeclampsia at <37 weeks gestation (preterm preeclampsia) and at any gestation (all preeclampsia) in each participant. The performance of screening for preterm preeclampsia and all preeclampsia by a combination of maternal factors, mean arterial pressure, uterine artery pulsatility index, and placental growth factor (triple test) was evaluated with the adjustment of aspirin use. We examined the predictive performance of the model by the use of receiver operating characteristic curve and calibration by measurements of calibration slope and calibration in the large. The detection rate of screening by the Fetal Medicine Foundation Bayes theorem-based model was compared with the model that was derived from the application of American College of Obstetricians and Gynecologists and National Institute for Health and Care Excellence recommendations.Results: There were 224 women (2.05%) who experienced preeclampsia, which included 73 cases (0.67%) of preterm preeclampsia. In pregnancies with preterm preeclampsia, the mean multiples of the median values of mean arterial pressure and uterine artery pulsatility index were significantly higher (mean arterial pressure, 1.099 vs 1.008 [P<.001]; uterine artery pulsatility index, 1.188 vs 1.063[P=.006]), and the mean placental growth factor multiples of the median was significantly lower (0.760 vs 1.100 [P<.001]) than in women without preeclampsia. The Fetal Medicine Foundation triple test achieved detection rates of 48.2%, 64.0%, 71.8%, and 75.8% at 5%, 10%, 15%, and 20% fixed false-positive rates, respectively, for the prediction of preterm preeclampsia. These were comparable with those of previously published data from the Fetal Medicine Foundation study. Screening that used the American College of Obstetricians and Gynecologists recommendations achieved detection rate of 54.6% at 20.4% false-positive rate. The detection rate with the use of National Institute for Health and Care Excellence guideline was 26.3% at 5.5% false-positive rate.Conclusion: Based on a large number of women, this study has demonstrated that the Fetal Medicine Foundation Bayes theorem-based model is effective in the prediction of preterm preeclampsia in an Asian population and that this method of screening is superior to the approach recommended by American College of Obstetricians and Gynecologists and the National Institute for Health and Care Excellence. We have also shown that the Fetal Medicine Foundation prediction model can be implemented as part of routine prenatal care through the use of the existing infrastructure of routine prenatal care. [ABSTRACT FROM AUTHOR]

Background: Microdeletions and microduplications can occur in any pregnancy independent of maternal age. The spectrum and features of pathogenic copy number variants including the size, genomic distribution, and mode of inheritance are not well studied. These characteristics have important clinical implications regarding expanding noninvasive prenatal screening for microdeletions and microduplications.Objectives: The aim was to investigate the spectrum and characteristics of pathogenic copy number variants in prenatal genetic diagnosis and to provide recommendations for expanding the scope of noninvasive prenatal screening for microdeletions and microduplications.Study Design: This was a retrospective study of 1510 pregnant women who underwent invasive prenatal diagnostic testing by chromosomal microarray analysis. Prenatal samples were retrieved by amniocentesis or chorionic villus sampling and sent to our prenatal genetic diagnosis laboratory for chromosomal microarray analysis. The risk of carrying a fetus with pathogenic copy number variants is stratified by the patients' primary indication for invasive testing. We searched the literature for published prenatal chromosomal microarray data to generate a large cohort of 23,865 fetuses. The characteristics and spectrum of pathogenic copy number variants including the type of aberrations (gains or losses), genomic loci, sizes, and the mode of inheritance were studied.Results: Overall, 375 of 23,865 fetuses (1.6%) carried pathogenic copy number variants for any indication for invasive testing, and 44 of them (11.7%) involve 2 or more pathogenic copy number variants. A total of 428 pathogenic copy number variants were detected in these fetuses, of which 280 were deletions and 148 were duplications. Three hundred sixty (84.1%) were less than 5 Mb in size and 68 (15.9%) were between 5 and 10 Mb. The incidence of carrying a pathogenic copy number variant in the high-risk group is 1 in 36 and the low-risk group is 1 in 125. Parental inheritance study results were available for 311 pathogenic copy number variants, 71 (22.8%) were maternally inherited, 36 (11.6%) were paternally inherited, and 204 (65.6%) occurred de novo.Conclusion: Collectively, pathogenic copy number variants are common in pregnancies. High-risk pregnancies should be offered invasive testing with chromosomal microarray analysis for the most comprehensive investigation. Detection limits on size, parental inheritance, and genomic distribution should be carefully considered before implementing copy number variant screening in expanded noninvasive prenatal screening. [ABSTRACT FROM AUTHOR]

Background: The traditional approach to the assessment of labor progress is by digital vaginal examination; however, it is subjective and imprecise. Recent studies have investigated the role of transperineal ultrasonographic assessment of fetal head descent by measuring the angle of progression and head-perineum distance.Objective: The objective of this study was to evaluate factors that affected labor progress, which were defined by the transperineal ultrasonographic parameters, in women who achieved vaginal delivery.Study Design: This was a prospective longitudinal study performed in 315 women with singleton pregnancy who underwent labor induction at term between December 2016 and December 2017. Paired assessment of cervical dilation and fetal head station by vaginal examination and transperineal ultrasonographic assessment of fetal head descent (parasagittal angle of progression and head-perineum distance) were made serially after the commencement of labor induction until full cervical dilation. The researchers were blinded to the findings of the clinical team's vaginal examination and vice versa. The repeated measure data were analyzed by mixed effect models to identify the significant factors (age ≥35 years, obesity, parity, methods of labor induction, and epidural anesthesia) that affected the relationship between parasagittal angle of progression and head-perineum distance against fetal head station and cervical dilation.Results: The total number of paired vaginal examination and transperineal ultrasonographic assessments among the 261 women (82.9%) with vaginal delivery was 945, with a median of 3 per woman. The median assessment-to-assessment interval was 4.6 hours (interquartile range, 4.3-5.2). Multiparity and mechanical methods of labor induction were associated with a faster rate of fetal head descent, which was determined by head-perineum distance against fetal head station, than nulliparity and the use of a slow-release vaginal pessary, respectively. An additional increase of 0.10 cm in head-perineum distance was observed, for an unit increase in fetal head station in nulliparous women (P=.03) and women who had a slow-release vaginal pessary (P=.02), compared with multiparous women and those who had mechanical methods for labor induction. The use of epidural anesthesia was associated with a slower rate of fetal head descent, which was determined by both parasagittal angle of progression and head-perineum distance, against fetal head station. An additional decrease of 3.66 degrees in parasagittal angle of progression (P=.04) and an additional increase in 0.33 cm in head-perineum distance (P≤.001) were observed for a unit increase in fetal head station in women with the use of epidural anesthesia, compared with those without. Obese women had higher head-perineum distance overall, compared with normal weight women; at different cross-sections of time periods, obesity appeared to be associated with a slower rate of change between head-perineum distance and cervical dilation. Advanced maternal age did not affect transperineal ultrasound-determined labor progress (P>.05).Conclusion: Parity, methods of labor induction, the use of epidural anesthesia, and obesity affect labor progress, which has been illustrated objectively by serial transperineal ultrasonographic assessment of fetal head descent. [ABSTRACT FROM AUTHOR]

Objective: The objective of the study was to determine the likelihood ratio for trisomy 21 in Chinese fetuses with absent nasal bone (NB) at 11-14 weeks of gestation. Study Design: The NB was classified as present or absent in 8101 chromosomally/phenotypically normal or trisomy 21 pregnancies. The effect of crown rump length (CRL), nuchal translucency (NT), maternal age, and fetal karyotype on the incidence of absent NB was examined using logistic regression. Results: The NB was successfully examined in 7925 cases (97.8%). The incidence of absent NB in unaffected and trisomy 21 cases were 2.1% (164/7899) and 50% (13/26), respectively. CRL (odds ratio [OR], 0.9; 95% confidence interval [CI], 0.87-0.92), NT (OR, 1.7; 95% CI, 1.4-2.3), and trisomy 21 (OR, 22.3; 95% CI, 8.1-61) were significant independent predictors of likelihood of absent NB. Positive likelihood ratios (LR) for trisomy 21 in Chinese were lower than that of Caucasians for the equivalent CRL and NT measurements. Conclusion: Estimated risk for trimsomy 21 in Chinese incorporating nasal bone status should use LRs derived in Chinese rather than Caucasians. [Copyright &y& Elsevier]