Optimizing Cefazolin Prophylaxis in Obstetrical Patients with Reported Beta-Lactam Allergy Undergoing Cesarean Delivery.

OBJECTIVES: Evaluate the impact of an allergy history-guided algorithm for optimizing perioperative cefazolin use in patients with reported beta-lactam allergy undergoing cesarean delivery. METHODS: The Allergy Clarification for Cefazolin Evidence-based Prescribing Tool (ACCEPT) was developed through consensus by allergists, anesthesiologists, and infectious diseases specialists, and implemented over a 2-month period (December 1, 2018, to January 31, 2019). A segmented regression on monthly cefazolin use was conducted during the baseline (January 1 to November 30, 2018) and intervention (February 1 to December 31, 2019) periods to evaluate the impact of ACCEPT on the monthly use of perioperative cefazolin in patients with reported beta-lactam allergy undergoing cesarean delivery. The frequency of perioperative allergic reactions and surgical site infections was collected during both periods. RESULTS: Of the 3128 eligible women who underwent a cesarean delivery, 282 (9%) reported a beta-lactam allergy. The most common beta-lactam allergens were penicillin (64.3%), amoxicillin (16.0%), and cefaclor (6.0%). The most frequently reported allergic reactions were rash (38.1%), hives (21.4%), and unknown (11.6%). Use of cefazolin increased from 52% (baseline) to 87% during the intervention period. Segmented regression analysis confirmed a statistically significant increase following implementation (incidence rate ratio 1.62, 95% CI 1.19-2.21, P = 0.002). There was 1 perioperative allergic reaction in the baseline period and 2 during the intervention period. Cefazolin use remained high (92%) 2 years after algorithm implementation. CONCLUSIONS: Implementation of a simple allergy history-guided algorithm in obstetrical patients with reported beta-lactam allergy resulted in a sustained increase in perioperative cefazolin prophylaxis.

Improving Intrapartum Group B Streptococcus Prophylaxis in Patients with a Reported Penicillin or Cephalosporin Allergy: A Quality Improvement Project.

OBJECTIVE: To evaluate the impact of a standardized allergy-guided approach to Group B Streptococcus (GBS) prophylaxis in pregnant women with reported penicillin or cephalosporin allergy. METHODS: This interrupted time-series analysis included obstetric patients requiring GBS prophylaxis who reported penicillin or cephalosporin allergies. Patients were divided into baseline (April 1, 2019 to July 21, 2020) and intervention (July 22, 2020 to July 31, 2021) groups. The primary outcome was prophylaxis appropriateness, based on antibiotic type, nature of reaction, and cross-reactivity risk. Secondary outcomes included type of prophylaxis received and antibiotic-related adverse events. RESULTS: The study included 88 patients in the baseline period and 52 patients in the intervention period. Appropriate prophylaxis increased from 47% (41/88) to 85% (44/52), with the segmented regression model confirming a statistically significant increase over time (incidence rate ratio 1.57; 95% CI 1.02-2.43, P = 0.04, slope coefficient 1.06/month; 95% CI 1.01-1.10, P = 0.01). Penicillin and cefazolin use increased from 61% (54/88) to 87% (45/52) in the intervention period (P = 0.002), and no hypersensitivity reactions occurred during this period. CONCLUSIONS: Implementation of standardized allergy-guided prophylaxis safely improved appropriate ß-lactam antibiotic use in obstetric patients requiring GBS prophylaxis who reported penicillin and cephalosporin allergies.

Timing of antenatal corticosteroids in relation to clinical indication.

PURPOSE: This study aimed at determining the proportion of women who receive antenatal corticosteroids (ACS) within the optimal time window before birth based on the indication for ACS, and to explore in more detail indications that are associated with suboptimal timing. METHODS: A retrospective cohort study of all women who received ACS in a single tertiary center between 2014 and 2017. The primary outcome was an ACS-to-birth interval ≤ 7 days. Secondary outcomes were ACS-to-birth interval of ≤ 14 days, and the proportion women who received ACS but ultimately gave birth at term (≥ 370/7 weeks). The study outcomes were stratified by the clinical indication for ACS. RESULTS: A total of 1261 women met the study criteria, of whom 401 (31.8%) and 569 (45.1%) received ACS within ≤ 7 days and ≤ 14 days before birth, respectively, and 203 (16.1%) ultimately gave birth at term. The proportion of women who received ACS within 7 days before birth was highest for women with preeclampsia (50.4%), and was lowest for women with an incidental finding of a short cervix (8.4%). In the subgroup of women with an incidental finding of a short cervix, the likelihood of optimal timing was not related to the magnitude of cervical shortening, history of preterm birth, multifetal gestation, presence of cervical funneling, or the presence of cervical cerclage. CONCLUSION: Over two-thirds of infants who are exposed to ACS do not get the maximal benefit from this intervention. The current study identified clinical indications for ACS that are associated with suboptimal timing of ACS where more research is needed to develop quantitative, indication-specific prediction models to guide the timing of ACS.

Patterns of discordant growth and adverse neonatal outcomes in twins.

BACKGROUND: Intertwin size discordance is an independent risk factor for adverse neonatal outcomes in twin pregnancies. However, size discordance at a given point in gestation fails to take into consideration information, such as the timing of onset and the rate of progression of discordance, that may be of prognostic value. OBJECTIVE: In this study, we aimed to identify distinct patterns of discordant fetal growth in twin pregnancies and to determine whether these patterns are predictive of adverse pregnancy outcomes. STUDY DESIGN: This was a retrospective cohort study of women with twin pregnancies in a single tertiary referral center between January 2011 and April 2020, who had at least 3 ultrasound examinations during pregnancy that included assessment of fetal biometry. Size discordance was calculated at each ultrasound examination, and pregnancies were classified into 1 of 4 predetermined patterns based on the timing of onset and the progression of discordance: pattern 1, no significant discordance group (referent); pattern 2, early (<24 weeks' gestation) progressive discordance group; pattern 3, early discordance with plateau group; or pattern 4, late (≥24 weeks' gestation) discordance group. The associations of discordance pattern (using pattern 1 as referent) with preterm birth, preeclampsia, size discordance at birth, and birthweight<10th percentile were expressed as adjusted relative risk with 95% confidence intervals and were compared with those observed for a single measurement of size discordance at 32 weeks' gestation. RESULTS: Of 2075 women with a twin gestation who were identified during the study period, 1059 met the study criteria. Of the 1059 women, 599 (57%) were classified as no significant discordance (pattern 1), 23 (2%) as early progressive discordance (pattern 2), 160 (15%) as early discordance with plateau (pattern 3), and 277 (26%) as late discordance (pattern 4). The associations of discordance pattern with preterm birth at <34 weeks' gestation and preeclampsia were strongest for pattern 2 (rates of 43% [adjusted relative risk, 3.43; 95% confidence interval, 2.10-5.62] and 17% [adjusted relative risk, 5.81; 95% confidence interval, 2.31-14.60], respectively), intermediate for pattern 3 (rates of 23% [adjusted relative risk, 1.82; 95% confidence interval, 1.28-2.59] and 6% [adjusted relative risk, 2.08; 95% confidence interval, 1.01-4.43], respectively), and weakest for pattern 4 (rates of 12% [adjusted relative risk, 0.96; 95% confidence interval, 0.65-1.42] and 4% [adjusted relative risk, 1.41; 0.68-2.92], respectively). In contrast, a single measurement of size discordance at 32 weeks' gestation showed no association with preeclampsia and only a weak association with preterm birth at <34 weeks' gestation. CONCLUSION: We identified 4 distinct discordance growth patterns among twins that demonstrated a dose-response relationship with adverse outcomes and seemed to be more informative than a single measurement of size discordance.

Gestational diabetes and fetal growth in twin compared with singleton pregnancies.

BACKGROUND: Gestational diabetes mellitus is associated with accelerated fetal growth in singleton pregnancies but may affect twin pregnancies differently because of the slower growth of twin fetuses during the third trimester of pregnancy and their greater predisposition to fetal growth restriction. OBJECTIVE: This study aimed to evaluate the association of gestational diabetes mellitus with longitudinal fetal growth in twin pregnancies and to compare this association with that observed in singleton pregnancies. STUDY DESIGN: This was a retrospective cohort study of all women with a singleton or twin pregnancy who were followed up at a single tertiary referral center between January 2011 and April 2020. Data on estimated fetal weight and individual fetal biometric indices were extracted from ultrasound examinations of eligible women. Generalized linear models were used to model and compare the change in fetal weight and individual biometric indices as a function of gestational age between women with and without gestational diabetes mellitus in twin pregnancies and between women with and without gestational diabetes mellitus in singleton pregnancies. The primary outcome was estimated fetal weight as a function of gestational age. The secondary outcomes were longitudinal growth of individual fetal biometric indices and the rate of small for gestational age and large for gestational age at birth. RESULTS: A total of 26,651 women (94,437 ultrasound examinations) were included in the analysis: 1881 with a twin pregnancy and 24,770 with a singleton pregnancy. The rate of gestational diabetes mellitus in the twin and singleton groups was 9.6% (n=180) and 7.6% (n=1893), respectively. The estimated fetal weight in singleton pregnancies with gestational diabetes mellitus was significantly higher than that in pregnancies without gestational diabetes mellitus (P<.001) starting at approximately 30 weeks of gestation. The differences remained similar after adjusting for maternal age, chronic hypertension, nulliparity, and neonatal sex (P<.001). In twin pregnancies, fetal growth was similar between pregnancies with and without gestational diabetes mellitus (P=.105 and P=.483 for unadjusted and adjusted models, respectively). The findings were similar to the association of gestational diabetes mellitus with the risk of large for gestational fetuses and the growth of each biometric index. When stratified by type of gestational diabetes mellitus treatment, twin pregnancies with gestational diabetes mellitus was associated with accelerated fetal growth only in the subgroup of women with medically treated gestational diabetes mellitus (P<.001), which represented 12% (n=21) of the twin pregnancy group with gestational diabetes mellitus. CONCLUSION: In contrast to singleton pregnancies, twin pregnancies with gestational diabetes mellitus is less likely to be associated with accelerated fetal growth. This finding has raised the question of whether the diagnostic criteria for gestational diabetes mellitus and the blood glucose targets in women diagnosed with gestational diabetes mellitus should be individualized for twin pregnancies.

Comparison of sonographic fetal weight estimation formulas in patients with preterm premature rupture of membranes.

BACKGROUND: Estimation of fetal weight (EFW) by ultrasound is useful in clinical decision-making. Numerous formulas for EFW have been published but have not been validated in pregnancies complicated by preterm premature rupture of membranes (PPROM). The purpose of this study is to compare the accuracy of EFW formulas in patients with PPROM, and to further evaluate the performance of the most commonly used formula - Hadlock IV. METHODS: A retrospective cohort study of women with singleton gestations and PPROM, admitted to a single tertiary center between 2005 and 2017 from 220/7-330/7 (n = 565). All women had an EFW within 14 days of delivery by standard biometry (biparietal diameter, head circumference, abdominal circumference and femur length). The accuracy of previously published 21 estimated EFW formulas was assessed by comparing the Pearson correlation with actual birth weight, and calculating the random error, systematic error, proportion of estimates within 10% of birth weight, and Euclidean distance. RESULTS: The mean gestational was 26.8 ± 2.4 weeks at admission, and 28.2 ± 2.6 weeks at delivery. Most formulas were strongly correlated with actual birth weight (r > 0.9 for 19/21 formulas). Mean systematic error was - 4.30% and mean random error was 14.5%. The highest performing formula, by the highest proportion of estimates and lowest Euclidean distance was Ott (1986), which uses abdominal and head circumferences, and femur length. However, there were minimal difference with all of the first 10 ranking formulas. The Pearson correlation coefficient for the Hadlock IV formula was strong at r = 0.935 (p < 0.001), with 319 (56.5%) of measurements falling within 10%, 408 (72.2%) within 15% and 455 (80.5%) within 20% of actual birth weight. This correlation was unaffected by gender (r = 0.936 for males, r = 0.932 for females, p < 0.001 for both) or by amniotic fluid level (r = 0.935 for mean vertical pocket < 2 cm, r = 0.943 for mean vertical pocket ≥2 cm, p < 0.001 for both). CONCLUSIONS: In women with singleton gestation and PPROM, the Ott (1986) formula for EFW was the most accurate, yet all of the top ten ranking formulas performed quite well. The commonly used Hadlock IV performed quite similarly to Ott's formula, and is acceptable to use in this specific setting.

Pathologic Basis for the Definition of Discordant Growth in Dichorionic Twins.

OBJECTIVE: The aim of the current study was to identify the optimal cutoff that should define discordance in dichorionic twin gestations through correlation with abnormal placental pathology as a specific measure of fetal growth restriction of the smaller twin. METHODS: We performed a retrospective cohort study of all women with dichorionic twin pregnancies who gave birth in a single center between 2002 and 2015. We investigated the association between the level of growth discordance and maternal vascular malperfusion (MVM) pathology in the placenta of the smaller twin, with and without adjustment for whether the smaller twin is small for gestational age (SGA). RESULTS: A total of 1,198 women with dichorionic twin gestation met the study criteria. The rate of MVM pathology in the placenta of the smaller twin increased with the level of discordance and was most obvious for discordance ≥25% (rate of MVM 12.0% compared with 2.8% in cases with discordance <10%, adjusted relative risk [aRR] 3.71, 95% confidence interval [CI] 1.97-6.99). When the analysis was adjusted for SGA of the smaller twin, discordance was independently associated with MVM pathology only when growth discordance was ≥25% (aRR 2.18, 95%-CI 1.01-4.93), while SGA was strongly associated with MVM pathology irrespective of the level of discordance. CONCLUSION: Our findings suggest that discordant growth in dichorionic twins should raise the concern of fetal growth restriction of the smaller twin, irrespective of whether the smaller twin is SGA, only when the discordance s ≥25%. The association of lower levels of discordance with abnormal placental pathology is mainly driven by the confounding effect of SGA of the smaller twin.

Delivery of monochorionic twins: lessons learned from the Twin Birth Study.

BACKGROUND: The current literature regarding the recommended mode of delivery of monochorionic-diamniotic twins is limited to small numbers, retrospective studies, and comparisons of outcomes of monochorionic-diamniotic twin pregnancies with those of dichorionic-diamniotic twin pregnancies instead of outcomes of trial of labor vs elective cesarean delivery of monochorionic-diamniotic twins. OBJECTIVE: This study aimed to compare perinatal and maternal outcomes of planned cesarean delivery and planned vaginal delivery of monochorionic-diamniotic twins using the Twin Birth Study data. STUDY DESIGN: This study is a secondary analysis of the Twin Birth Study. Women were randomized from 32 weeks and 0 days gestation to 38 weeks and 6 days gestation to planned cesarean delivery or planned vaginal delivery. Twin A in the cephalic presentation and estimated weight of each twin between 1500 and 4000 grams were the inclusion criteria. Pregnancies complicated by fetal reduction after 13 weeks of gestation, lethal fetal anomaly, or contraindication to vaginal delivery were excluded. Elective delivery was planned between 37 weeks and 5 to 7 days of gestation and 38 weeks and 6 to 7 days of gestation. Perinatal and maternal outcomes of monochorionic-diamniotic twin pregnancies were compared between those randomized for planned cesarean delivery and those randomized for planned vaginal delivery. In addition, outcomes of monochorionic-diamniotic twin pregnancies were compared with those of dichorionic-diamniotic twin pregnancies. RESULTS: Out of the 1393 women in each arm, 346 (24.9%) women in the planned cesarean delivery arm and 324 (23.3%) women in the planned vaginal delivery arm had monochorionic-diamniotic twin pregnancies and were eligible for the first analysis. The rate of cesarean delivery was 39.2% in the planned vaginal delivery arm and was 91.3% in the planned cesarean delivery arm. There was no significant difference in gestational age at delivery between the groups (34.4±1.8 weeks vs 34.5±1.8 weeks; P=.78). No difference was found in maternal outcomes. As for perinatal outcomes, the rate of the primary adverse neonatal composite outcomes in twins A or twins B was similar in both the planned vaginal delivery and the planned cesarean delivery arms (twins A, 1.2% vs 1.2% [P=.92]; twins B, 1.2% vs 3.2% [P=.09]). Within the planned cesarean delivery arm, the rate of primary adverse neonatal composite outcome was higher in twins B than twins A (3.2% vs 1.2%; P=.03). There was no difference in the primary adverse neonatal composite outcome between twins A in the monochorionic-diamniotic group and the dichorionic-diamniotic group (1.2% vs 1.3%; P=.89) or between twins B in similar groups (2.3% vs 2.7%; P=.47). CONCLUSION: In monochorionic-diamniotic twin pregnancy between 32 weeks and 0 to 7 days of gestation and 38 weeks and 6 to 7 days of gestation, with twin A in a cephalic presentation, planned cesarean delivery did not decrease or increase the risk of fetal or neonatal death or serious neonatal morbidity, as compared with planned vaginal delivery.

Comparing Foley Catheter to Prostaglandins for Cervical Ripening in Multiparous Women.

OBJECTIVE: This study sought to test the hypothesis that among multiparous women requiring cervical ripening, mechanical ripening with a Foley catheter is more effective than prostaglandin preparations. METHODS: This was a retrospective analysis of multiparous women with a singleton gestation who required cervical ripening in a single tertiary center from 2014 to 2019. Women who underwent cervical ripening with a Foley catheter (Foley group) were compared with women who underwent cervical ripening using a controlled-release dinoprostone vaginal insert (PGE2-CR group) or dinoprostone vaginal gel (PGE2-gel group). The primary outcome was the ripening-to-delivery interval. RESULTS: A total of 229 women met the study criteria (Foley group: 95; PGE2-CR group: 83; PGE2-gel group: 51). Women in the Foley group had a significantly shorter ripening-to-delivery interval compared with women in the PGE2-CR group (16.2 ± 9.2 hours vs. 27.0 ± 14.8 hours; P < 0.001) and were more likely to deliver within 12 hours (47.4% vs. 12.0%; P < 0.001; adjusted relative risk [aRR] 3.87; 95% confidence interval [CI] 2.07-7.26) and within 24 hours (78.9% vs. 49.4%; P < 0.001; aRR 1.61; 95% CI 1.26-2.06). Women in the Foley group were also less likely to require a second ripening method compared with women in the PGE2-CR group (1.1% vs. 8.4%; P = 0.018; aRR 7.26; 95% CI 2.99-17.62). These differences were not observed when comparing the Foley and the PGE2-gel groups. The cesarean section rate was similar among the Foley group (9.5%), PGE2-CR group (9.6%; P = 0.970), and PGE2-gel group (11.8%; P = 0.664). CONCLUSION: In multiparous women requiring cervical ripening, all methods of cervical ripening have a similar success rate. However, the use of a PGE2-CR insert is associated with a considerably longer interval to delivery compared with a Foley catheter or PGE2 gel.

Examining Cesarean Section Rates in Canada Using the Modified Robson Classification.

OBJECTIVE: Canada's cesarean delivery (CD) rate continues to increase. The Society of Obstetricians and Gynaecologists of Canada advocates the use of the modified Robson classification for comparisons. This study describes national and provincial CD rates according to this classification system. METHODS: All 2016-2017 in-hospital births in Canada (outside Québec) reported to the Discharge Abstract Database were categorized using the modified Robson classification system. CD rates, group size, and contributions of each group to the overall volume of CD were reported. Rates by province and hospital peer group were also examined (Canadian Task Force Classification III). RESULTS: A total of 286 201 women gave birth; among these, 83 262 (29.1%) had CDs. Robson group 5 (term singleton previous CD) had a CD rate of 80.5% and was the largest contributing group to the overall number of CD (36.6%). Women whose labour was induced (Robson group 2A) had a CD rate almost double the rate of women with spontaneous labour (Robson group 1): 33.5% versus 18.4%. These latter two groups made the next largest contributions to overall CD (15.7% and 14.1%, respectively). There were substantial variations in CD rates across provinces and among hospital peer groups. CONCLUSION: The study found large variations in CD rates across provinces and hospitals within each Robson group, thus suggesting that examining variations to determine the groups contributing the most to CD rates (Robson groups 5, 2A, and 1) may provide valuable insight for reducing CD rates. This study provides a benchmark for measuring the impact of future initiatives to reduce CD rates in Canada.

Removal vs. retention of cervical cerclage in pregnancies complicated by preterm premature rupture of membranes: a retrospective study.

PURPOSE: To compare pregnancy outcomes in women with pPROM and a cervical cerclage in whom the cerclage was removed within 24 h and those in whom the cerclage was retained in situ. METHODS: A two-center retrospective cohort study of women with a singleton gestation with pPROM at < 340/7 weeks of gestation in the presence of cervical cerclage (January 1, 2012-July 30, 2016). Maternal and perinatal outcomes were compared between women in whom cerclage was removed within 24 h from pPROM and those in whom cerclage was retained until the onset of delivery. The primary outcome was time from pPROM to delivery. RESULTS: Seventy women met inclusion criteria. Cerclage was left in situ in 47 (67.1%) and removed in 23 (32.9%) women. Women in the cerclage retention group had a higher pPROM-to-delivery interval (7.0 ± 7.2 vs. 6.0 ± 10.9 days, p = 0.03), and were more likely to have a latency period > 48 h (87.2% vs. 65.2%, p = 0.03; aOR 3.9, 95% CI 3.1-4.9) or > 7 days (29.8% vs. 8.7%, p = 0.04; aOR 7.0, 95% CI 2.5-19.6) compared with women in whom cerclage was removed. Furthermore, chorioamnionitis rate was lower in the cerclage retention group compared to cerclage removal group (aOR 0.7, 95% CI 0.5-1.0). There were no differences between the groups in early neonatal sepsis, severe brain injury, or composite neonatal outcome. CONCLUSION: In women with pPROM and cervical cerclage, retention of cerclage may be associated with a longer latency period, and a lower chorioamnionitis rate, without an associated increase in the risk of neonatal infectious morbidity. Presentation information: The abstract of this study was presented as a poster at the 38th SMFM (Society of Maternal and Fetal Medicine) annual meeting, February 2018, Dallas, Texas, USA.

Association between hypertensive disorders and fetal growth restriction in twin compared with singleton gestations.

BACKGROUND: Hypertensive disorders of pregnancy (including preeclampsia or gestational hypertension) are associated with fetal growth restriction in singleton pregnancies, an association that may be attributed to abnormal placentation as the shared etiology between these conditions. Given that the pathogenesis of these conditions in twin pregnancies may involve mechanisms other than abnormal placentation, it is unclear whether a similar association between hypertensive disorders of pregnancy and fetal growth restriction is present in twins. Data on the relationship between hypertensive disorders of pregnancy and fetal growth restriction in twins are limited and conflicting. This controversy may be attributed to limitations of existing studies including the use of a singleton-based birthweight reference to define fetal growth restriction in twins and the lack of a positive control group of singleton gestations. OBJECTIVE: The objective of the study was to determine the association between hypertensive disorders of pregnancy and fetal growth restriction in dichorionic twin gestations, using both a singleton- and a twin-based birthweight reference, and to compare this association with that observed in singleton gestations. STUDY DESIGN: We performed a retrospective cohort study of all women with dichorionic twin or singleton gestations giving birth in a single tertiary center during 2003-2015. Fetal growth restriction was defined in separate analyses as birthweight <10th percentile for gestational age using either a singleton- or a twin-based birthweight reference. The association between hypertensive disorders of pregnancy and fetal growth restriction was determined separately for twin and singleton gestations and was expressed as adjusted relative risk with 95% confidence interval. RESULTS: A total of 1520 twin and 48,943 singleton gestations were included. In singleton gestations, hypertensive disorders of pregnancy were associated with an increased risk of fetal growth restriction (16.6% vs 7.4%, adjusted relative risk, 2.07, 95% confidence interval, 1.87-2.30). In twins, there was no association between hypertensive disorders of pregnancy and fetal growth restriction when a singleton-based reference was used to define fetal growth restriction. However, when using a twin-based reference to define fetal growth restriction, hypertensive disorders of pregnancy in twin gestations were associated with a similar increase in the risk of fetal growth restriction to that seen in singletons (11.8% vs 4.7%, adjusted relative risk, 2.37, 95% confidence interval, 1.69-3.34). Findings were similar with regard to the reverse association between fetal growth restriction and hypertensive disorders of pregnancy: in women with twin gestations, the increase in the risk of hypertensive disorders of pregnancy in pregnancies complicated by fetal growth restriction of 1 twin was similar to that observed in singletons only when a twin-based reference was used to define fetal growth restriction (twins: 21.3% vs 9.8%, adjusted relative risk, 2.15, 95% confidence interval, 1.63-3.06; singletons: 8.8% vs 3.7%, adjusted relative risk, 2.19, 95% confidence interval, 1.95-2.44). CONCLUSION: The association between hypertensive disorders of pregnancy and fetal growth restriction in dichorionic twins is similar in magnitude to that observed in singletons so long as appropriate birthweight references are applied. Therefore, women with a twin gestation complicated by one of these conditions should be closely monitored for the other. Our findings suggest that the use of a twin-based reference to diagnose fetal growth restriction in twin gestations may be more informative and clinically relevant than using a singleton-based reference.

The worst of both worlds-combined deliveries in twin gestations: a subanalysis of the Twin Birth Study, a randomized, controlled, prospective study.

OBJECTIVE: The reported incidence of combined twin delivery (vaginal delivery of twin A followed by cesarean delivery for twin B) ranges between 5% and 10%. These estimates are based mostly on small studies or retrospective data. We aimed to evaluate to incidence and risk factors for and outcomes of combined twin deliveries, using a subanalysis of the Twin Birth Study, a randomized, controlled, prospective study. STUDY DESIGN: The Twin Birth Study included women with twin gestation between 32+0 and 38+6 weeks, with the first twin in vertex presentation at randomization. Women were randomized to planned cesarean delivery or planned vaginal delivery. For the purpose of this subanalysis, we included women who had a vaginal delivery of twin A. Women who had a combined delivery (cesarean delivery for twin B) were compared with women who had a vaginal delivery of both twins. Our primary objective was to identify risk factors for combined twin deliveries. Our secondary objective was to assess the rate of fetal/neonatal death or serious neonatal morbidity in combined deliveries. RESULTS: Of the 2786 women included in the original study, 842 women delivered twin A by a vaginal delivery and were included in the current analysis, of whom 59 (7%) had a combined delivery. Women in the combined delivery group had a lower rate of nulliparity (22.0% vs 34.7%, P = 0.047) and higher rates of noncephalic presentation of twin B at delivery (61.0% vs 27.3%, P < 0.001) and spontaneous version from presentation at randomization of twin B (72.9% vs 44.3%, P < 0.0001). In a multivariable model, the only risk factor significantly associated with a combined delivery was transverse/oblique lie of twin B following delivery of twin A (adjusted odds ratio, 47.7; 95% confidence interval, 15.4-124.5). Twins B in the combined delivery group had a higher rate of fetal/neonatal death or serious neonatal morbidity (13.6% vs 2.3%, P < 0.001), 5-minute Apgar score <7, neonatal intensive care unit admission, abnormal level of consciousness, and assisted ventilation. CONCLUSION: Transverse/oblique lie of twin B following vaginal delivery of twin A is a risk factor for combined delivery. Combined delivery is associated with higher risk of adverse neonatal outcomes of twin B. These data may be used to better counsel women with twin gestation who consider a trial of labor.

Defining early vs late fetal growth restriction by placental pathology.

INTRODUCTION: Although early and late fetal growth restriction have been suggested to be distinct entities, the optimal gestational age cut-off that differentiates the two conditions is currently unclear and has been arbitrarily set in previous studies between 32 and 37 weeks. We aimed to use placental pathology findings to determine that optimal gestational age cut-off between early and late fetal growth restriction. MATERIAL AND METHODS: A retrospective cohort study of all women with singleton gestation who gave birth to a neonate diagnosed as small-for-gestational age (small-for-gestational age, defined as birthweight <10th percentile for gestational age) at a tertiary referral center between January 2001 and December 2015, and for whom placental pathology was available. Placental abnormalities were classified into lesions associated with maternal vascular malperfusion (MVM), fetal vascular malperfusion, placental hemorrhage and chronic villitis. Placental findings were analyzed as a function of gestational age at birth. The analysis was repeated in the subgroups of women without hypertensive complications of pregnancy (to reflect changes associated with isolated small-for-gestational age) and of neonates with severe small-for-gestational age (defined as birthweight <5th percentile), which are more likely to represent true fetal growth restriction. RESULTS: A total of 895 women met the inclusion criteria. The only histological finding that changed with gestational age was MVM pathology, which decreased in frequency with increasing gestational age. We identified a considerable drop in the rate of MVM lesions at 33 weeks of gestation. The rate of MVM pathology in placentas of infants born before 330/7  weeks was significantly higher than that observed in placentas of infants born at 330/7  weeks or longer: 71.6% vs 27.4%, P < 0.001 for ≥2 MVM lesions, and 35.5% vs 3.5%, P < 0.001 for ≥3 MVM lesions. These findings persisted in the subgroups of women without hypertensive complications of pregnancy (n = 662) and of neonates with severe small-for-gestational age (n = 464). CONCLUSIONS: Using placental pathology as a direct measure of the mechanisms underlying fetal growth restriction, the optimal gestational age at birth cut-off which differentiates early from late fetal growth restriction appears to be 330/7  weeks.

Respiratory morbidity in late preterm twin infants.

PURPOSE: Antenatal corticosteroids have been shown to decrease neonatal respiratory morbidity in singleton pregnancies when given during the late-preterm period (340/7-366/7 weeks). Whether these findings also apply to late-preterm twins, who account for approximately one-third of infants born at 340/7-356/7 weeks, is currently unclear. The answer to this question depends, in part, on whether the risk of respiratory morbidity among late-preterm twin infants is similar to that observed in late-preterm singletons. We aimed to assess the rate of respiratory morbidity among late-preterm twin infants using a secondary analysis of prospectively collected data from a large international multicenter trial, and to compare that rate with previous studies that used the same definition of respiratory morbidity. STUDY DESIGN: This was a secondary analysis of the twin birth study. In the current study, we limited the analysis to women who gave birth during the late preterm period. The primary outcomes were the same primary composite respiratory morbidity variables that were used in the randomized controlled trial of Gyamfi-Bannerman et al., on the administration of betamethasone during the late preterm period in singletons (ALPS trial). The risk of respiratory morbidity among late preterm twins was stratified by gestational week at birth. RESULTS: A total of 1163 women who gave birth to 2324 late preterm twin infants met the inclusion criteria. The rates of respiratory morbidity and severe respiratory morbidity were 16.5% and 8.9%, respectively. The risk of respiratory morbidity was highly dependent on gestational week at birth, being more than fourfold for infants born at 340/7-346/7 weeks (aOR 4.30, 95%-CI 3.01-6.14) and more than twofold for infants born at 350/7-356/7 weeks (aOR 2.12, 95%-CI 1.51-2.98) compared with infants born at 360/7-366/7 weeks. The rate of respiratory morbidity and the theoretical number of women needed to be treated with betamethasone to prevent a single case of respiratory morbidity in the current study were similar to those reported in the APLS trial (16.5% vs. 14.4%, p = 0.103, and NNT 31 vs. 34, respectively). CONCLUSIONS: The risk-benefit ratio of betamethasone with regard to neonatal respiratory morbidity in women with twins at risk of late-preterm birth is expected to be similar to that observed in singletons.

Mild neonatal morbidity in twins by planned mode of delivery: a secondary analysis of the Twin Birth Study.

BACKGROUND: The Twin Birth Study showed no differences in major severe adverse neonatal outcomes between those with planned vaginal delivery and those with planned cesarean delivery. OBJECTIVE: This was a secondary analysis of the Twin Birth Study in which mild neonatal morbidities, not previously reported, were compared between parturients with planned cesarean deliveries and those with planned vaginal delivery in twin births. STUDY DESIGN: This was a secondary analysis of the Twin Birth Study. In this study, women with a twin pregnancy at 32+0/7 to 38+6/7 weeks of gestation with the first twin in cephalic presentation and with an estimated weight between 1500 and 4000 g were randomized to either planned cesarean delivery or planned vaginal delivery. The primary outcome of this study was a composite mild neonatal outcome of respiratory and neurologic morbidities and neonatal intensive care unit admission that were not reported in the original Twin Birth Study at 34+0/7 to 38+6/7 weeks of gestation. A multivariable logistic regression analysis was used to identify factors associated with the composite adverse neonatal outcomes. Neonatal outcomes were further stratified by gestational age at delivery and by actual mode of delivery. RESULTS: A total of 1304 women and 1326 women were randomly assigned to planned cesarean delivery and planned vaginal delivery, respectively. Demographic and obstetrical characteristics were similar between the study groups. The rate of cesarean delivery was 90.1% in the planned cesarean delivery group and 40.1% in the planned vaginal delivery group. There was no significant difference in the primary composite outcome between the groups (10.6% vs 11.3%; P=.45) neither by planned mode of delivery nor by actual mode of delivery. Stratification by gestational age found a lower rate of the primary outcomes at ≥38+0/7 weeks of gestation in the planned cesarean delivery group when compared with the planned vaginal delivery group (4.8% vs 10.8%, respectively; P=.02). Furthermore, a lower risk for some individual outcomes was reported in the planned cesarean delivery group when compared with the planned vaginal delivery group, including intraventricular hemorrhage stage 1 to 2 (0.2% vs 0.6%; P<.05), low Apgar scores (0.8% vs 2.3%; P<.05), pH <7.0 (0.3 vs 1%; P<.05), and assisted ventilation needed at delivery (0.4% vs 0.9%; P<.05). CONCLUSION: In twin deliveries, with the first twin in the cephalic presentation, composite mild neonatal morbidity was not affected by the planned mode of delivery. These findings reinforce the original results of the Twin Birth Study. Nevertheless, an increased composite outcome after 38 weeks' gestation and a higher risk for some individual morbidities in the planned vaginal delivery group might be viewed as a concerning signal for the safety of vaginal delivery in twin deliveries and requires further research.

The accuracy of Fetoplacental Doppler in distinguishing between growth restricted and constitutionally small fetuses.

INTRODUCTION: Fetoplacental Doppler is considered to be a key tool for the diagnosis of placenta-mediated fetal growth restriction(FGR). We aimed to determine the diagnostic accuracy of fetoplacental Doppler for specific placental diseases. METHODS: A retrospective cohort study of all women with a singleton pregnancy and an antenatal diagnosis of SGA fetus(estimated fetal weight <10th centile for gestational age), who underwent fetoplacental Doppler assessment within 2 weeks before birth. Primary exposure was any abnormal Doppler result, defined as an abnormal umbilical artery(UA) Doppler, middle cerebral artery(MCA) Doppler, cerebroplacental-ratio(CPR), or umbilico-cerebral ratio(UCR). Study outcomes were abnormal placental pathology: maternal vascular malperfusion(MVM), villitis of unknown etiology(VUE), or fetal vascular malperfusion(FVM). RESULTS: A total of 558 women with a singleton SGA fetus were included, of whom 239(42.8%) had an abnormal fetoplacental Doppler findings. UA Doppler had the lowest detection rate for abnormal placental pathology. MCA Doppler exhibited a significantly higher detection rate for all types of pathology. CPR and UCR exhibited highest detection rates for all types of placental pathology, however, were also associated with the highest false positive rate. The combination of fetoplacental Doppler with the severity of SGA and maternal hypertensive status achieved a high negative predictive value MVM lesions(97%). In contrast, fetoplacental Doppler did not improve the negative predictive value for non-MVM pathology(VUE or FVM). DISCUSSION: Among SGA fetuses, the combination of UA and MCA Doppler is highly accurate in ruling out FGR due to MVM placental pathology, but is of limited value in excluding FGR due to underlying non-MVM pathologies.

Antenatal corticosteroids and neurodevelopmental outcomes in late preterm births.

OBJECTIVES: Antenatal corticosteroids (ACS) decrease neonatal mortality and morbidity among preterm neonates, yet there has been concern regarding their long-term safety. We hypothesised that potential long-term adverse effects of ACS may be observed among infants born during the late preterm period (LPT, 340/7-366/7 weeks of gestation), when the benefits of ACS are subtle. DESIGN: Population-based, retrospective cohort. SETTING: Ontario, Canada, between 2006 and 2011. PATIENTS: All live singleton infants born during the LPT period with a minimum 5-year follow-up. INTERVENTIONS: Exposure to ACS prior to 340/7 weeks of gestation. MAIN OUTCOME MEASURES: Suspected neurocognitive disorder, audiometry testing or visual testing. RESULTS: Overall, 25 668 infants were eligible for analysis, of whom 2689 (10.5%) received ACS. Infants in the ACS group had lower mean birth weight and higher rates of birth weight <10th percentile, neonatal resuscitation and neonatal intensive care unit admission. At 5 years of age, ACS exposure was associated with an increased risk of suspected neurocognitive disorder (adjusted HR (aHR) 1.12, 95% CI 1.05 to 1.20), audiometry testing (aHR 1.20, 95% CI 1.10 to 1.31) and visual testing (aHR 1.06, 95% CI 1.01 to 1.11). CONCLUSION: In children born during the LPT period, exposure to ACS prior to 340/7 weeks of gestation is associated with an increased utilisation of the healthcare system related to audiometry and visual testing and suspected neurocognitive disorders by 5 years of age.