The Feasibility of a Trial of Labor after Two Cesarean Deliveries: Outcomes and Prognostic Factors for Success.

OBJECTIVE: This study aimed to determine whether a trial of labor after two cesarean deliveries (TOLAC2) increases the risk of adverse maternal and neonatal outcomes and identify prognostic factors for TOLAC2 success. STUDY DESIGN: A retrospective cohort study was conducted at a single medical center. The study group was comprised of women with a history of TOLAC2. Outcomes were compared with women undergoing trial of labor after one previous cesarean delivery (TOLAC1). The primary outcome was trial of labor after cesarean delivery (TOLAC) success. Secondary outcomes included mode of delivery, uterine rupture, and combined adverse outcome (CAO; uterine rupture, postpartum hemorrhage, 5-minute Apgar score < 7, pH < 7.1). Logistic regression was used for the multivariate analysis to identify prognostic factors for TOLAC2 success. RESULTS: A total of 381 women who underwent TOLAC2 were compared with 3,635 women who underwent TOLAC1. Women attempting TOLAC2 were less likely to achieve vaginal births after cesarean delivery (VBAC; 80.8 and 92.5%; odds ratio [OR]: 0.35; 95% confidence interval [CI]: 0.26-0.47; p < 0.001) and more likely to experience uterine rupture (0.8 vs. 0.2%; OR: 4.1; 95% CI: 1.1-15.9; p = 0.02) but not CAO (4.2 vs. 4.8%; OR: 0.88; 95% CI: 0.5-1.5; p = 0.3). TOLAC2 women with no previous vaginal deliveries had a lower chance of VBAC and a higher risk of uterine rupture compared with TOLAC1 women without a prior vaginal delivery (45.2 vs. 86.3%; OR: 0.13; 95% CI: 0.07-0.25; p < 0.001; 2.3 vs. 0%) and TOLAC2 women with a prior vaginal delivery (45.2 vs. 85.3%; OR: 0.14; 95% CI: 0.1-0.3; p < 0.0001; 2.4 vs. 0.6%; OR: 4.1; 95% CI: 0.4-46.3; p = 0.3). Multivariate analysis revealed that a history of vaginal delivery is an independent predictor of TOLAC2 success. CONCLUSION: Women attempting TOLAC2 are less likely to achieve VBAC and are at greater risk of uterine rupture compared with those attempting TOLAC1. Despite these risks, the overall success rates remain very high, and the absolute risk of adverse outcomes is still very low. Prior vaginal delivery seems to have a protective effect on TOLAC outcomes. These data should be used to counsel women and assist in decision-making when considering the mode of delivery in women with two previous cesarean sections. KEY POINTS: · TOLAC2 has a lower chance of success and higher rate of uterine rupture compared with TOLAC1.. · Previous vaginal delivery is an independent predictor of TOLAC2 success.. · Overall TOLAC2 outcomes are associated with high chances of success and low risk of uterine rupture..

Assessment of uterine contractions in labor and delivery.

Normal labor and delivery are dependent on the presence of regular and effective contractions of the uterine myometrium. The mechanisms responsible for the initiation and maintenance of adequate and synchronized uterine activity that are necessary for labor and delivery result from a complex interplay of hormonal, mechanical, and electrical factors that have not yet been fully elucidated. Monitoring uterine activity during term labor and in suspected preterm labor is an important component of obstetrical care because cases of inadequate and excessive uterine activity can be associated with substantial maternal and neonatal morbidity and mortality. Inadequate labor progress is a common challenge encountered in intrapartum care, with labor dystocia being the most common indication for cesarean deliveries performed during labor. Hereafter, an accurate assessment of uterine activity during labor can assist in the management of protracted labor by diagnosing inadequate uterine activity and facilitating the titration of uterotonic medications before a trial of labor is prematurely terminated. Conversely, the ability to diagnose unwanted or excessive uterine activity is also critical in cases of threatened preterm labor, tachysystole, or patients undergoing a trial of labor after cesarean delivery. Knowledge of uterine activity in these cases may guide the use of tocolytic medications or raise suspicion of uterine rupture. Current diagnostic capabilities are less than optimal, hindering the medical management of term and preterm labor. Currently, different methods exist for evaluating uterine activity during labor, including manual palpation, external tocodynamometry, intrauterine pressure monitoring, and electrical uterine myometrial activity tracing. Legacy uterine monitoring techniques have advantages and limitations. External tocodynamometry is the most widespread tool in clinical use owing to its noninvasive nature and its ability to time contractions against the fetal heart rate monitor. However, it does not provide information regarding the strength of uterine contractions and is limited by signal loss with maternal movements. Conversely, the intrauterine pressure catheter quantifies the strength of uterine contractions; however, its use is limited by its invasiveness, risk for complications, and limited additive value in all but few clinical scenarios. New monitoring methods are being used, such as electrical uterine monitoring, which is noninvasive and does not require ruptured membranes. Electrical uterine monitoring has yet to be incorporated into common clinical practice because of lack of access to this technology, its high cost, and the need for appropriate training of clinical staff. Further work needs to be done to increase the accessibility and implementation of this technique by experts, and further research is needed to implement new practical and useful methods. This review describes current clinical tools for uterine activity assessment during labor and discusses their advantages and shortcomings. The review also summarizes current knowledge regarding novel technologies for monitoring uterine contractions that are not yet in widespread use, but are promising and could help improve our understanding of the physiology of labor, delivery, and preterm labor, and ultimately enhance patient care.

Induction of Labor in Twins-Double Trouble?

OBJECTIVE: To determine and compare the safety and efficacy of different methods of induction of labor in twin gestations and their effect on maternal and neonatal outcomes. METHODS: A retrospective observational cohort study was conducted at a single university-affiliated medical center. Patients with a twin gestation undergoing induction of labor at >32 + 0 weeks comprised the study group. Outcomes were compared to patients with a twin gestation at >32 + 0 weeks who went into labor spontaneously. The primary outcome was cesarean delivery. Secondary outcomes included operative vaginal delivery, postpartum hemorrhage, uterine rupture, 5 min APGAR < 7, and umbilical artery pH < 7.1. A subgroup analysis comparing outcomes for the induction of labor with oral prostaglandin E1 (PGE1), IV Oxytocin ± artificial rupture of membranes (AROM), and extra-amniotic balloon (EAB)+ IV Oxytocin was performed. Data were analyzed using Fisher's exact test, ANOVA, and chi-square tests. RESULTS: 268 patients who underwent induction of labor with a twin gestation comprised the study group. 450 patients with a twin gestation who went into labor spontaneously comprised the control group. There were no clinically significant differences between the groups for maternal age, gestational age, neonatal birthweight, birthweight discordancy, and non-vertex second twin. There were significantly more nulliparas in the study group compared to the control group (23.9% vs. 13.8% p < 0.001). The study group was significantly more likely to undergo a cesarean delivery of at least one twin (12.3% vs. 7.5% OR, 1.7 95% CI 1.04-2.85 p = 0.03). However, there was no significant difference in the rate of operative vaginal delivery (15.3% vs. 19.6% OR, 0.74, 95% CI 0.5-1.1 p = 0.16), PPH (5.2% vs. 6.9% OR, 0.75 95% CI 0.39-1.42 p = 0.37), 5-min APGAR scores < 7 (0% vs. 0.2% OR, 0.99 95%CI 0.99-1.00 p = 0.27), umbilical artery pH < 7.1 (1.5% vs. 1.3% OR, 1.12 95% CI 0.3-4.0), or combined adverse outcome (7.8% vs. 8.7% OR, 0.93 95% CI 0.6-1.4 p = 0.85). Furthermore, there were no significant differences in the rates of cesarean delivery or combined adverse outcomes in patients undergoing induction with oral PGE1 compared to IV Oxytocin ± AROM (13.3% vs. 12.5% OR, 1.1 95% CI 0.4-2.0 p = 1.0) (7% vs. 9.3% OR, 0.77 95% CI 0.5-3.5 p = 0.63 ) or EAB+ IV Oxytocin (13.3% vs. 6.9% OR, 2.1 95% CI 0.1-2.1 p = 0.53) (7% vs. 6.9% OR, 1.4 95% CI 0.15-3.5 p = 0.5) or between patients undergoing induction of labor with IV Oxytocin ± AROM and EAB+ IV Oxytocin (12.5% vs. 6.9% OR, 2.1 95% CI 0.1-2.4 p = 0.52) (9.3% vs. 6.9% OR, 0.98 95% CI 0.2-4.7 p = 0.54). There were no cases of uterine rupture in our study. CONCLUSIONS: Induction of labor in twin gestations is associated with a two-fold increased risk of cesarean delivery, although this is not associated with adverse maternal or neonatal outcomes. Furthermore, the method of induction of labor used does not affect the chances of success nor the rate of adverse maternal or neonatal outcomes.

Fetal and neonatal brain injury in twins complicated by twin anemia polycythemia sequence.

OBJECTIVES: To determine the rate of fetal and neonatal brain lesions and define risk factors for such lesions in pregnancies complicated by Twin Anemia Polycythemia Sequence (TAPS). METHODS: A retrospective cohort study of monochorionic twin pregnancies which were diagnosed with TAPS in a single tertiary medical center between 2013 and 2021. Pregnancies were followed with fetal brain neurosonogram every 2 weeks and fetal brain MRI (magnetic resonance imaging) was performed when indicated at 28-32 weeks of gestation; post-natal brain imaging included neonatal brain ultrasound. Pregnancies with pre- and post-natal brain lesions were compared to those without such findings. RESULTS: Overall, 23 monochorionic diamniotic pregnancies were diagnosed with TAPS over the study period resulting in perinatal survival of 91.3% (42/46). In 6/23 (26%) pregnancies and 7/46 (15.2%) fetuses pre- or post-natal brain lesions were detected, of whom five were the polycythemic twins and two were the anemic twins. Brain findings included intra-cerebral hemorrhage and ischemic lesions and were diagnosed prenatally in 6/7 (85.7%) cases. No risk factors for severe brain lesions were identified. CONCLUSIONS: TAPS may place the fetuses and neonates at increased risk for cerebral injuries. Incorporation of fetal brain imaging protocols may enhance precise prenatal diagnosis and allow for accurate parental counseling and post-natal care.

Feasibility of Fetal Proximal Lateral Cerebral Ventricle Measurement.

OBJECTIVES: Measuring the posterior horn of the lateral ventricle in the fetus during ultrasound scans may be challenging. We aimed to examine this measurement feasibility, in relation to gestational age. METHODS: A cross-sectional study was conducted, including nonanomalous fetuses, in which both lateral ventricles measured less than 10 mm during anomaly scans. The measurements were performed according to the International Society of Ultrasound in Obstetrics and Gynecology guidelines. Success rate of measuring both ventricles was assessed at different gestational ages. Association between lateral ventricle width with contralateral ventricle width, gender, gestational age, and fetal head position were assessed. RESULTS: A total of 156 cases were recruited. The lateral ventricle distal to the probe was measured in all cases. In 10 cases proximal lateral ventricle could not be adequately measured (failed proximal ventricle measurement group). In 146 scans both ventricle measurements were available. All 10 cases of failed proximal ventricle measurement were in third trimester (30-38 weeks). Success rate of measurement of both ventricles was 100%, 96.2%, 71.4%, and 37.5% for gestational week 14-29, 30-32, 33-35, and 36-38, respectively (P <.001). Proximal lateral ventricle width was strongly associated with the distal ventricle width (B = 0.422, 95% confidence interval 0.29, 0.555, P <.001), but not with head position, fetal gender, or gestational age. CONCLUSIONS: Measurement of the proximal lateral ventricle is feasible in most cases, even during late third trimester scans. Efforts should be made to visualize both ventricles in every evaluation of the fetal brain.

Association between level of training and reliability of intrapartum transperineal ultrasound measurement of angle of progression.

OBJECTIVES: Intrapartum transperineal ultrasound (ITU) is an accepted tool for assessing fetal head position and station prior to operative vaginal delivery attempt. However, the validity of intrapartum ultrasound in real-life obstetrics with operators at different proficiency level is yet to be established. We aimed to investigate the association between operator level of training and reliability of angle of progression (AOP) measurements in real-life obstetrics. METHODS: This was a retrospective study in one university medical center. We included women who underwent ITU for the measurement of AOP, before vacuum assisted delivery from November 2017 to September 2020. AOP measurements performed by residents and their correlation to head station were compared to those performed by specialists. RESULTS: A total of 320 cases met the inclusion criteria. In 234 of them, AOP measurements were performed by specialists and in 86 by residents. Average AOP for each station was similar between the specialists and the residents groups, indicating similar accuracy. However, measurements in the residents group were more scattered (median deviation 11.4° vs. 8.9°, respectively, p = .021), indicating poorer precision. CONCLUSIONS: AOP measurements performed by obstetrics and gynecology (OBGYN) specialists are more precise than those performed by residents. Efforts should be taken to improve ITU training and to implement assessment of performance programs.

Fetal and neonatal brain lesions following laser ablation for twin-to-twin-transfusion-syndrome as detected by pre- and post-natal brain imaging.

OBJECTIVE: To determine the rate of and risk factors for fetal and neonatal brain lesions following laser ablation for twin-to-twin transfusion syndrome (TTTS). METHODS: A retrospective cohort study of 83 women with monochorionic twin pregnancies who underwent ablation for TTTS at a single tertiary hospital. Post-laser survivors were followed-up with fetal neurosonogram every 2 weeks and fetal brain MRI at 28-32 weeks of gestation; post-natal brain imaging included neurosonogram. Cases with pre- and post-natal brain lesions were compared to those without. RESULTS: 153 fetuses survived the immediate post-laser period and underwent brain imaging. Of these, 17 (11.11%) exhibited brain lesions on prenatal imaging studies, and 36 (32.4%) on post-natal ultrasound. Later gestational age (GA) at the time of ablation (23.0 vs. 21.4 weeks, p = 0.0244), post-laser twin-anemia-polycythemia-sequence (TAPS) (29.41% vs. 9.56%, p = 0.035) and birthweight discordancy (30% vs. 9%, p = 0.0025) were associated with prenatal brain lesions. Earlier GA at delivery (31.0 weeks vs. 32.2, p = 0.0002) and post-laser TAPS (25% vs. 9.33%, p = 0.038) were associated with post-natal brain lesions. CONCLUSIONS: Survivors of ablation for TTTS are at risk for brain lesions, which can be detected prenatally. Incorporation of neurosonogram and fetal brain MRI into the routine surveillance of such pregnancies should be considered.

Fetal and Perinatal Outcome Following First and Second Trimester COVID-19 Infection: Evidence from a Prospective Cohort Study.

A novel coronavirus termed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a new strain of coronavirus causing coronavirus disease 2019 (COVID-19) disease, which emerged as a global pandemic. Data regarding the implications of COVID-19 disease at early gestation on fetal and obstetric outcomes is scarce. Thus, our aim was to investigate the effect of first and second trimester maternal COVID-19 disease on fetal and perinatal outcomes. This was a prospective cohort study of pregnant women with a laboratory-proven SARS-COV-2 infection contracted prior to 26 weeks gestation. Women were followed at a single tertiary medical center by serial sonographic examinations every 4-6 weeks to assess fetal well-being, growth, placental function, anatomic evaluation and signs of fetal infection. Amniocentesis was offered to assess amniotic fluid SARS-COV-2-PCR (polymerase chain reaction) and fetal brain magnetic resonance imaging (MRI) was offered at 30-32 weeks gestation. Demographic, obstetric and neonatal data were collected from history intake, medical charts or by telephone survey. Perinatal outcomes were compared between women infected at first vs. second trimester. 55 women with documented COVID-19 disease at early gestation were included and followed at our center. The mean maternal age was 29.6 ± 6.2 years and the mean gestational age at viral infection was 14.2 ± 6.7 weeks with 28 (51%) women infected at the first trimester and 27 (49%) at the second trimester. All patients but one experienced asymptomatic to mild symptoms. Of 22 patients who underwent amniocentesis, none had evidence of vertical transmission. None of the fetuses exhibited signs of central nervous system (CNS) disease, growth restriction and placental dysfunction on serial ultrasound examinations and fetal MRI. Pregnancies resulted in perinatal survival of 100% to date with mean gestational age at delivery of 38.6 ± 3.0 weeks and preterm birth <37 weeks rate of 3.4%. The mean birthweight was 3260 ± 411 g with no cases of small for gestational age infants. The obstetric and neonatal outcomes were similar among first vs. second trimester infection groups. We conclude SARS-CoV-2 infection at early gestation was not associated with vertical transmission and resulted in favorable obstetric and neonatal outcomes.

Differences in fetal growth patterns between twins and singletons.

Objective: Twin fetus growth is delayed during the third trimester compared to singletons. Whether this phenomenon should be considered a normal physiologic characteristic of twins or a pathologic process inherent to twin pregnancies is currently unclear. Information on the growth rate of the individual fetal biometric indices may provide more insight into the mechanisms underlying these differences between twins and singletons. Our aim was to compare fetal growth pattern between twin and singleton fetuses.Methods: This was a retrospective study of women with an uncomplicated twin pregnancy who underwent sonographic fetal weight estimation between 16 and 38 weeks' gestation in a single referral center. Twins-specific regression models were generated for biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), femur length (FL) and fetal weight as a function of gestational age and were compared to published singletons-based curves.Results: Overall 543 women were eligible for the study and underwent a total of 3401 sonographic weight estimations. Estimated weight of twin fetus emerged as lower than that of singletons starting at 26 weeks of gestation, and these differences increased with gestational age, reaching a mean difference of 300-350 g or of ∼10% at term. The growth of all four biometric indices was slower in twins compared to singletons, but the differences were most pronounced for AC which had the largest relative contribution to the lower fetal weight in twins (51.7 ± 7.3%), while the relative contribution of FL, HC, and BPD was smaller (26.4 ± 10.7, 15.5 ± 3.0, and 6.4%±5.7%, respectively). This was also reflected by a higher HC/AC ratio in twins compared with singletons starting at 22 weeks of gestation. The likelihood of a twin fetus being diagnosed as small for gestational age (fetal weight <10th percentile) was significantly lower when the newly developed twins-based curves (rather than singletons-based curves) were used (OR: 0.39, 95%-CI: 0.34-0.44).Conclusion: Twin fetus experience slowing of growth beginning at ∼26 weeks of gestation and a greater degree of asymmetric growth pattern compared with singletons. These findings suggest that the slower growth of twins may reflect a state of "relative growth restriction" compared with singleton gestations.

The role of serial measurements of cervical length in asymptomatic women with triplet pregnancy.

OBJECTIVE: To assess the predictive accuracy of serial measurements of cervical length (CL) for preterm birth in asymptomatic women with triplet pregnancy. METHODS: A retrospective study of women with triplets who underwent serial sonographic measurements of CL until 28-32 weeks of gestation. The predictive accuracy of CL for preterm birth was determined at 4 periods along gestation: 18-20 weeks (period 1), 21-24 weeks (period 2), 25-27 weeks (period 3) and 28-32 weeks (period 4). RESULTS: A total of 431 measurements of CL from were analyzed. CL decreased in a linear manner across gestation: 40.8 ± 7.1 mm, 36.5 ± 8.4 mm, 29.9 ± 11.4 mm and 25.0 ± 11.8 mm in periods 1, 2, 3 and 4, respectively. The difference in CL between women who did and did not deliver prematurely was small before 25 weeks (periods 1&2) but became more pronounced later in pregnancy (periods 3&4), mainly due to a rapid cervical shortening between periods 2 and 3 (shortening rate -29.0 ± 20.0% vs. -12.6 ± 20.5%, respectively, p = .01). The best predictors of preterm birth were either a single measurement of CL during period 3 or the degree of cervical shortening between periods 2 and 3. CONCLUSIONS: Care providers should be aware of the limited predictive value of cervical length before 25 + 0 weeks in triplet pregnancies.

Delivery outcomes of large-for-gestational-age newborns stratified by the presence or absence of gestational diabetes mellitus.

OBJECTIVE: To evaluate separate and combined contributions of gestational diabetes mellitus (GDM) and large-for-gestational age (LGA) on delivery outcomes. METHODS: In a retrospective cohort study of term singleton deliveries between 2007 and 2014 in Tel Aviv, Israel, outcomes were compared between non-GDM/AGA pregnancies (reference) and three study groups: non-GDM/LGA, GDM/appropriate for gestational age (AGA) and GDM/LGA. RESULTS: Overall, there were 62 102 deliveries, of which 53 201 (85.7%) were eligible for inclusion. Of these, 43 775 (82.3%) were non-GDM/AGA, 6441 (12.1%) non-GDM/LGA, 2351 (4.4%) GDM/AGA, and 634 (1.2%) GDM/LGA. Compared with the reference group, the study groups had higher mean maternal age and higher rates of previous cesarean delivery, polyhydramnios, induction of labor, and cesarean delivery. Considering only women attempting vaginal delivery, the three groups were independently associated with adverse outcomes including cesarean delivery (adjusted odds ratio [aOR], 1.5, 1.6, and 2.6 for non-GDM/LGA, GDM/AGA, and GDM/LGA, respectively), mainly for prolonged first stage of labor, and hypoglycemia (aOR, 1.9, 2.5, and 4.6, respectively). LGA with and without GDM was associated with shoulder dystocia (aOR, 14.5 and 6.9, respectively), prolonged second stage, and jaundice. CONCLUSION: GDM and LGA share similarities in pregnancy complications. The presence of both has a cumulative impact.

Simulator Based Obstetric Ultrasound Training: A Prospective, Randomized Single-Blinded Study.

OBJECTIVE: To compare the use of simulator-based and patient-based obstetric ultrasound training. METHODS: This was a prospective, randomized, single-blinded trial. Eighteen consenting obstetric trainees with minimal previous ultrasound exposure were recruited. Enrolled patients were also fully consenting. Mid-trimester fetal brain anatomy in the standard planes (i.e., biparietal diameter and head circumference, cavum septum pellucidum, posterior fossa, and lateral ventricle) was chosen as a surrogate for all fetal anatomy ultrasound training. Trainees were randomized into two groups according to training method: simulator group (n = 9) or patient group (n = 9). All participating trainees went through the following sequence: a didactic session regarding the required planes; a "real" patient 15-minute pretest; a 45-minute training session with a dedicated ultrasound educator, using either a simulator or a "real" patient (according to the randomized group assignment); and a 15-minute post-test to obtain and label the standard four planes on a "real" patient. All images were stored and then scored by two blinded Maternal Fetal Medicine staff, according to 3 set criteria: image quality, landmarks, and measurements. Each criterion was scored 0 to 15 for a total score of 0 to 60. RESULTS: Pretest competence was similar between the two groups. For each of the two groups there was a significant score improvement following training: real patient (mean score pretest 13.3 vs. post-test 24.6; P < 0.04) and simulator group (mean score pretest 15.9 vs. post-test 28.9; P < 0.05). All trainees demonstrated significant overall score improvements (mean score pretest 14.6 vs. post-test 26.6; P < 0.04) regardless of training method. Trainees were further divided by their initial level of confidence (pretest score ≤5: very unconfident; pretest >5: unconfident). The improvement was similar for both groups, but "very unconfident" trainees' performance improved more in the simulator group (mean pretest vs. post-test score 3.5 to 35) compared with the patient group (mean pretest vs. post-test score 2.3 to 25.6) CONCLUSION: Simulator-based obstetric ultrasound training performed as well as real patient training and was found to be especially beneficial for beginner trainees. Simulator-based ultrasound training has a high rate of acceptance by trainees, does not require investment of patient or clinic resources, and warrants consideration as an educational tool for the safe and effective teaching of obstetric ultrasound.

The greater risk of preterm birth in triplets is mirrored by a more rapid cervical shortening along gestation.

BACKGROUND: The risk of preterm birth increases with plurality. However, data are limited about the role of cervical length in triplet pregnancies and how the greater predisposition for preterm birth in triplet pregnancies, compared with twin pregnancies, is reflected by cervical length. Specifically, it is unclear whether the greater predisposition of triplet pregnancies for preterm birth is reflected by a more rapid cervical shortening during gestation compared with twin pregnancies (and therefore a shorter cervical length at any given gestational age), by a greater risk for preterm birth per given cervical length at any given gestational age, or both. OBJECTIVE: The purpose of the study was to compare the rate of cervical shortening during gestation and the correlation between cervical length and gestational age at birth in asymptomatic women with triplet vs twin pregnancies. STUDY DESIGN: This was a retrospective study of women with triplet or twin pregnancies who were who were observed in a tertiary center who underwent serial sonographic measurement of cervical length from 16-32 weeks gestation. Change in cervical length during gestation and relationship of cervical length with gestational age at birth were compared between the triplets and twins groups. RESULTS: A total of 431 measurements of cervical length from 86 women with triplets was analyzed and compared with 2826 measurements of cervical length from 441 women with twins. The rate of cervical shortening among triplet pregnancies was higher than among twin pregnancies starting from 18 weeks of gestation (slope of regression line, -1.297 vs -0.907; P < .001). Similarly, the proportion of women with cervical length of <25 mm or 15 mm was higher among triplet pregnancies than among twin pregnancies (34.0% vs 21.0% [P < .001] and 16.7% vs 8.4% [P = .001]), respectively. For any given cervical length measured after 22 weeks of gestation, the associated gestational length at birth in triplet pregnancies was lower by 2.7 weeks on average compared with twin pregnancies (P < .001). CONCLUSION: The higher rate of preterm birth in triplet pregnancies, compared with twin pregnancies, is reflected by both a more rapid cervical shortening during gestation and a lower gestational age at birth per any given cervical length.

Risk factors for obstetric anal sphincter injuries in twin deliveries: a retrospective review.

INTRODUCTION AND HYPOTHESIS: Risk factors for obstetric anal sphincter injuries (OASIS) have been well-established in singleton pregnancies. Considering the unique characteristics of twin deliveries, our aim was to identify risk factors for OASIS that are specific to twins. METHODS: A retrospective study of all vaginal twin deliveries in a tertiary center between 2000 and 2014. Women who experienced OASIS (the OASIS group) were compared with those whose anal sphincter was intact (controls). RESULTS: Overall 717 women were eligible for the study, of whom 20 (2.8 %) experienced OASIS. Women in the OASIS group were more likely to be nulliparous (95.0 % vs 53.7 %, p < 0.001) and were characterized by a higher gestational age at delivery (36.1 ± 2.5 vs 34.6 ± 3.3, p = 0.04), a higher birth weight for both twin A and twin B (2,507 ± 540 g vs 2,254 ± 525 g, p = 0.03, and 25,49 ± 420 g vs 2,232 ± 606 g, p = 0.004 respectively), and a higher rate of episiotomy (40.0 % vs 14.2 %, p = 0.001), instrumental delivery for twin A (80.0 % vs 13.5 %, p < 0.001) or twin B (80.0 % vs 18.7 %, p < 0.001), and inter-twin delivery interval of over 30 min (20.0 % vs 7.5 %, p = 0.04). The only factor that remained significant on multivariate analysis was instrumental delivery: forceps delivery of twin A (OR = 8.8, 95 % CI 2.6-30.1), vacuum extraction of twin A (OR = 9.2, 95 % CI 2.6-34.6), and forceps delivery of twin B (OR = 15.4, 95 % CI 4.9-48.6). In women with certain combinations of risk factors the risk of OASIS was as high as 30 %. CONCLUSION: The overall rate of OASIS in twins is low and instrumental delivery, especially by forceps, is a risk factor.

Is the risk of obstetric anal sphincter injuries increased in vaginal twin deliveries?

OBJECTIVE: Vaginal twin deliveries have a higher rate of intrapartum interventions. We aimed to determine whether these characteristics are associated with an increased rate of obstetric anal sphincter injuries compared with singleton. STUDY DESIGN: Retrospective study of all twin pregnancies undergoing vaginal delivery trial was conducted from January 2000-September 2014. Sphincter injury rate compared with all concurrent singleton vaginal deliveries. Multivariable analysis was used to determine twin delivery association with sphincter injuries while adjusting for confounders. RESULTS: About 717 eligible twin deliveries. Outcome was compared with 33 886 singleton deliveries. Twin pregnancies characterized by a higher rate of nulliparity (54.8% versus 49.5%, p = 0.005), labor induction (42.7% versus 29.1%, p < 0.001), and instrumental deliveries (27.5% versus 16.7%, p < 0.001), lower gestational (34.6 ± 3.3 versus 38.8 ± 2.3, p < 0.001), and lower birth weight. Total breech extraction was performed in 29.0% (208/717) of twin deliveries. Overall obstetric sphincter injury rate was significantly lower in the twins group (2.8% versus 4.4%, p = 0.03, OR = 0.6, 95% CI 0.4-0.9), due to lower rate of 3rd degree tears in twins versus singletons (2.2% versus 4.0%, p = 0.02), rate of 4th degree tears similar among the groups (0.6% versus 0.4%, p = 0.5). In multivariable analysis, sphincter injuries were associated with nulliparity (OR = 3.9, 95% CI 3.4-4.5), forceps (OR = 6.8, 95% CI 5.8-7.8), vacuum (OR = 2.9, 95% CI 2.5-3.3), earlier gestational age (OR = 0.2, 95% CI 0.1-0.3), episiotomy (OR = 0.8, 95% CI 0.7-0.9), and birth weight over 3500 g (OR = 1.8, 95% CI 1.6-2.0). However, the association between twins (versus singletons) deliveries and sphincter injuries was lost after adjustment for delivery gestational age (OR = 0.7, 95% CI 0.4-1.2). CONCLUSION: Despite a higher rate of intrapartum interventions, the rate of sphincter injuries is lower in twins versus singleton deliveries, mainly due to a lower gestational age at delivery.

The Likelihood of Change in Fetal Presentation During the Third Trimester in Twin Pregnancies.

OBJECTIVE: To estimate the likelihood and identify predictors of spontaneous fetal version during the third trimester in twins using data from a multicenter randomized controlled trial on mode of delivery in twin pregnancies. METHODS: Women with twin pregnancies after 32 weeks of gestation in which twin A was vertex were randomized to planned cesarean or planned vaginal delivery. In the current study we analyzed the likelihood of a spontaneous version of any of the twins between ultrasound assessment at the time of randomization and delivery. RESULTS: A total of 2,603 women were analyzed. Twin A tended to persist in the vertex presentation after 32 weeks of gestation with a spontaneous version rate to nonvertex presentation of 3.0% (95% confidence interval [CI] 2.3-3.7%). Twin B was less stable and underwent spontaneous version in 24.8% (95% CI 23.1-26.5%) of cases; the rate remained higher than 20% even after 34 weeks of gestation. On multivariable analysis, twin A was more likely to undergo version when twin B was smaller (adjusted odds ratio [OR] 2.0, 95% CI 1.04-3.3), when twin B was breech (adjusted OR 3.7, 95% CI 2.2-6.4) or transverse (adjusted OR 2.9, 95% CI 1.6-5.5), and when the interval to delivery exceeded 4 weeks (adjusted OR 2.5, 95% CI 1.3-5.0). Twin B was more likely to undergo version when it was in the breech presentation (adjusted OR 1.7, 95% CI 1.4-2.1) or transverse lie (adjusted OR 3.1, 95% CI 2.5-3.9) compared with vertex presentation, when it was smaller (adjusted OR 1.7, 95% CI 1.1-2.0), when the interval to delivery exceeded 4 weeks (adjusted OR 1.7, 95% CI 1.3-2.4), and in multiparous women (adjusted OR 1.3, 95% CI 1.04-1.5). CONCLUSION: The likelihood of spontaneous version of twin A after 32 weeks of gestation is low when twin A is in the vertex presentation but is much higher for twin B, even late during the third trimester. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, www.clinicaltrials.gov, NCT00187369. LEVEL OF EVIDENCE: II.

Maternal Obesity Class as a Predictor of Induction Failure: A Practical Risk Assessment Tool.

OBJECTIVE: To assess the impact of body mass index (BMI) on the rate of cesarean section (rCS) in induction of labor (IOL). STUDY DESIGN: A total of 7,543 singleton term pregnancies undergoing IOL (cervical dilatation at admission, CDA ≤ 3 cm) were divided according to BMI: underweight (n = 325); normal weight (NW) (n = 4,633); overweight (OW) (n = 1,610); and obese (n = 975). Age, parity, macrosomia, gestational age (GA), gestational weight gain (GWG), CDA, and IOL indications were considered. RESULTS: A higher rate of macrosomia (15.0 vs. 11.1%; p < 0.0001), earlier induction (GA 39.7 ± 1.3 vs. 40.1 ± 1.3 weeks; p < 0.0001) for maternal indications (39.1 vs. 21.1%; p < 0.001), and lower CDA (≤1cm; 66.4 vs. 61.4%; p < 0.005) were observed in obese versus NW. The rate of weight gain above the recommended range was higher in obese (obese 70.6% vs. NW 43.9%; p < 0.001), despite a significantly lower mean GWG compared with NW (14 ± 7.5 vs. 16.5 ± 5.6 kg; p < 0.001). Compared with NW, OW and obese demonstrated a significantly higher rCS (OW 31.1% and obese 36.9% vs. NW 24.7%; p < 0.001). BMI represented an independent factor affecting the rCS (vs. NW; OW odds ratio [OR] 1.4; confidence interval [CI] 1.2-1.7; p < 0.001; obese OR 2.3; CI 1.9-2.7 p < 0.001). CONCLUSION: In the case of IOL, obesity represents an independent factor associated with a significant increase of CS to be considered during induction counselling.

Does artificial rupturing of membranes in the active phase of labor enhance myometrial electrical activity?

OBJECTIVE: To determine whether artificial rupture of membranes (AROM) during active phase of labor augments uterine contractility using Electrical Uterine Myography (EUM). STUDY DESIGN: A prospective study of 31 women with term singleton pregnancy during active phase of labor. Using a non-invasive EUM technique, electrical uterine activity was recorded in the 30 min preceding AROM and in the immediate 30 min thereafter. Augmentation was defined as >5% increase in EUM index between the basal and post-AROM states, representing the mean EUM increase of the entire cohort. Low basal uterine contraction was defined as EUM index of less than the entire cohort median result prior AROM (3.5 micro-Watt-Second (mWS)). RESULTS: Mean dilatation in which AROM was preformed was 5.5 ± 1.8 cm. There was a significant increase in mean EUM measurement in the post-AROM compared to the basal state (3.59 ± 0.39 versus 3.42 ± 0.47 mWS, p < 0.001). In multivariate analysis, low BMI and low basal uterine contractions were the only significant predictors for augmentation following AROM (OR 0.69, 95% C.I 0.45-0.97, p = 0.009 and OR 16.03, 95% CI 1.90-134.69, p = 0.003, respectively). CONCLUSION: Myometrial electrical activity was significantly enhanced following AROM. Augmentation was mostly pronounced in patients with lower BMI and initial lower basal uterine contraction.

The association of crown-rump length discrepancy with birthweight discordance in spontaneous versus assisted conception dichorionic twins.

OBJECTIVE: This study aimed to compare the associations of crown-rump length (CRL) discrepancy with birthweight discordance in spontaneous versus vitro fertilization (IVF) conceived dichorionic twin pregnancies. METHOD: A computerized retrospective study of women referred to our ultrasonographic unit for nuchal translucency examination between January 1997 and December 2011. The study group was subdivided into twins conceived after IVF, non-IVF fertility treatment and spontaneously conceived twins. Birthweight discordance was defined as a difference of birthweights of >20%. RESULTS: A total of 688 dichorionic twin pregnancies were included, all of them ending in live birth of both twins. IVF-conceived pregnancies were associated with a significant increased risk of extreme birthweight discordance compared with spontaneous-conceived twin pregnancies (OR = 2.3; CI = 1.4-3.8, P < 0.001). A significant correlation was found between CRL discrepancy and birthweight discordance in spontaneous-conceived pregnancies (r = 0.15, P < 0.05). In contrast, there was no significant correlation between CRL discrepancy and birthweight discordance in both IVF and fertility treatment-conceived pregnancies. CONCLUSION: Because birthweight discordance in IVF-conceived twins did not correlate with CRL discrepancy, we assume that it emerges later in pregnancy, maybe related to maternal underplaying complications, for which IVF was indicated in the first place.

New onset of meconium during labor versus primary meconium-stained amniotic fluid - is there a difference in pregnancy outcome?

OBJECTIVE: To compare pregnancy outcome between deliveries complicated by new onset of meconium during labor following prior evidence of clear amniotic fluid and labors in which meconium was present to begin with. METHODS: A retrospective cohort study of all singleton term (≥37 + 0 weeks) deliveries complicated by intrapartum meconium-stained amniotic fluid in a tertiary referral medical center during the year 2012. Outcome was compared between deliveries with new onset of meconium during labor following prior evidence of clear amniotic fluid (secondary meconium group) and those in which meconium was already evident at the time of membranes rupture (primary meconium group). RESULTS: Of the 9167 deliveries during the study period, 694 were eligible for the study group. Of these, 537 were complicated by primary meconium and 157 by secondary meconium. Only secondary meconium, but not primary meconium, was independently associated with an increased risk of operative vaginal delivery (OVD) and adverse neonatal outcome. Pregnancies complicated by secondary meconium were independently associated with a higher rate of OVD (28.0% versus 11.4%, p < 0.001), POP position of the fetal head (6.4% versus 2.6%, p = 0.02), and adverse neonatal outcome (17.2% versus 8.9%, p = 0.003). CONCLUSION: Secondary meconium is associated with a higher rate of adverse obstetrical and neonatal outcome compared with primary meconium.