Maternal and perinatal outcomes after elective induction of labor at 39 weeks in uncomplicated singleton pregnancy: a meta-analysis

OBJECTIVE

The rate of maternal and perinatal complications increases after 39 weeks' gestation in both unselected and complicated pregnancies. The aim of this study was to synthesize quantitatively the available evidence on the effect of elective induction of labor at 39 weeks on the risk of Cesarean section, and on maternal and perinatal outcomes.

METHODS

PubMed, US Registry of Clinical Trials, SCOPUS and CENTRAL databases were searched from inception to August 2018. Additionally, the references of retrieved articles were searched. Eligible studies were randomized controlled trials of singleton uncomplicated pregnancies in which participants were randomized between 39 + 0 and 39 + 6 gestational weeks to either induction of labor or expectant management. The risk of bias of individual studies was assessed using the Cochrane Risk of Bias Tool. The overall quality of evidence was assessed according to the GRADE guideline. Primary outcomes included Cesarean section, maternal death and admission to the neonatal intensive care unit (NICU). Secondary outcomes included operative delivery, Grade-3/4 perineal laceration, postpartum hemorrhage, maternal infection, hypertensive disease of pregnancy, maternal thrombotic events, length of maternal hospital stay, neonatal death, need for neonatal respiratory support, cerebral palsy, length of stay in NICU and length of neonatal hospital stay. Pooled risk ratios (RRs) were calculated using random-effects models.

RESULTS

The meta-analysis included five studies (7261 cases). Induction of labor was associated with a decreased risk for Cesarean section (moderate quality of evidence; RR 0.86 (95% CI, 0.78-0.94); I²  = 0.1%), maternal hypertension (moderate quality of evidence; RR 0.65 (95% CI, 0.57-0.75); I²  = 0%) and neonatal respiratory support (moderate quality of evidence; RR 0.73 (95% CI, 0.58-0.95); I²  = 0%). Neonates born after induction weighed, on average, 81 g (95% CI, 63-100 g) less than those born after expectant management. No significant effects were found for the other outcomes with the available data. The main limitation of our analysis was that the majority of data were derived from a single large study. A second limitation arose from the open-label design of the studies, which may theoretically have affected the readiness of the attending clinician to resort to Cesarean section.

CONCLUSIONS

Elective induction of labor in uncomplicated singleton pregnancy at 39 weeks' gestation is not associated with maternal or perinatal complications and may reduce the need for Cesarean section, risk of hypertensive disease of pregnancy and need for neonatal respiratory support. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Vasa previa screening strategies: decision and cost-effectiveness analysis

OBJECTIVE

To perform a decision and cost-effectiveness analysis comparing four screening strategies for the antenatal diagnosis of vasa previa in singleton pregnancies.

METHODS

A decision-analytic model was constructed comparing vasa previa screening strategies. Published probabilities and costs were applied to four transvaginal screening scenarios that were carried out at the time of mid-trimester ultrasound: no screening, ultrasound-indicated screening, screening only pregnancies conceived by in-vitro fertilization (IVF) and universal screening. Ultrasound-indicated screening was defined as performing transvaginal ultrasound at the time of the routine anatomy ultrasound scan in response to one of the following sonographic findings associated with an increased risk of vasa previa: low-lying placenta, marginal or velamentous cord insertion or bilobed or succenturiate lobed placenta. The primary outcome was cost per quality-adjusted life year (QALY) in US$. The analysis was performed from a healthcare system perspective with a willingness-to-pay threshold of $100 000 per QALY selected. One-way and multivariate sensitivity analysis (Monte-Carlo simulation) was performed.

RESULTS

This decision-analytic model demonstrated that screening pregnancies conceived by IVF was the most cost-effective strategy, with an incremental cost effectiveness ratio (ICER) of $29186.50/QALY. Ultrasound-indicated screening was the second most cost-effective, with an ICER of $56096.77/QALY. These data were robust to all one-way and multivariate sensitivity analyses performed.

CONCLUSIONS

Within the baseline assumptions, transvaginal ultrasound screening for vasa previa appears to be most cost-effective when performed among IVF pregnancies. However, both IVF and ultrasound-indicated screening strategies fall within contemporary willingness-to-pay thresholds, suggesting that both strategies may be appropriate to apply in clinical practice. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Customized fetal growth standard compared with the INTERGROWTH-21st century standard at predicting small-for-gestational-age neonates

INTRODUCTION

The INTERGROWTH-21st project (IG-21) was recently performed aiming to provide a universal benchmark for comparing fetal growth across different ethnicities. Our aim was to compare the IG-21 with a customized standard for predicting pregnancies at risk for neonatal small-for-gestational age (SGA) and adverse outcomes.

MATERIAL AND METHODS

This was a prospective cohort study including singleton pregnancies presenting for fetal growth assessment between 26 and 36 weeks of gestation. Fetal growth restriction was defined as estimated fetal weight <10th centile for gestational age using IG-21 and a customized standard. Neonatal SGA was defined as birthweight <10th centile for gestational age by the Alexander chart. Primary outcome was the prediction of neonatal SGA. Secondary outcomes included a composite of adverse neonatal outcomes. The discriminatory ability of each growth standard was compared using area under receiver operating characteristic curves (AUC).

RESULTS

Of 1054 pregnancies meeting the inclusion criteria, the incidence of neonatal SGA was 139 (13.2%), and a composite adverse neonatal outcome occurred in 300 (28.4%). The sensitivity of the customized standard (38.8%) was higher than that of IG-21 (24.5%) for predicting neonatal SGA, with AUC (95% CI) of 0.67 (0.63-0.71) for customized vs 0.62 (0.58-0.65) for IG-21; P = .003. Both standards were comparable in predicting the composite adverse neonatal outcomes: AUC (95% CI) 0.52 (0.50-0.55) for customized vs 0.51 (0.50-0.53) for IG-21; P = 0.25.

CONCLUSIONS

Both growth standards had modest performance in detecting neonatal SGA and were poor at predicting short-term adverse neonatal outcome.

Weight discordance and perinatal mortality in twin pregnancy: systematic review and meta-analysis

OBJECTIVES

The primary aim of this systematic review was to explore the strength of association between birth-weight (BW) discordance and perinatal mortality in twin pregnancy. The secondary aim was to ascertain the contribution of gestational age and growth restriction in predicting mortality in growth-discordant twins.

METHODS

MEDLINE, EMBASE, CINAHL and ClinicalTrials.gov databases were searched. Only studies reporting on the risk of mortality in twin pregnancies affected compared with those not affected by BW discordance were included. The primary outcomes explored were incidence of intrauterine death (IUD), neonatal death (NND) and perinatal death. Outcome was assessed separately for monochorionic (MC) and dichorionic (DC) twin pregnancies. Analyses were stratified according to BW discordance cut-off (≥ 15%, ≥ 20%, ≥ 25% and ≥ 30%) and selected gestational characteristics, including incidence of IUD or NND before and after 34 weeks' gestation, presence of at least one small-for-gestational age (SGA) fetus in the twin pair and both twins being appropriate-for-gestational age. Risk of mortality in the larger vs smaller twin was also assessed. Meta-analyses using individual data random-effects logistic regression and meta-analyses of proportion were used to analyze the data.

RESULTS

Twenty-two studies (10 877 twin pregnancies) were included in the analysis. In DC pregnancies, a higher risk of IUD, but not of NND, was observed in twins with BW discordance ≥ 15% (odds ratio (OR) 9.8, 95% CI, 3.9-29.4), ≥ 20% (OR 7.0, 95% CI, 4.15-11.8), ≥ 25% (OR 17.4, 95% CI, 8.3-36.7) and ≥ 30% (OR 22.9, 95% CI, 10.2-51.6) compared with those without weight discordance. For each cut-off of BW discordance explored in DC pregnancies, the smaller twin was at higher risk of mortality compared with the larger one. In MC twin pregnancies, excluding cases affected by twin-twin transfusion syndrome, twins with BW discordance ≥ 20% (OR 2.8, 95% CI, 1.3-5.8) or ≥ 25% (OR 3.2, 95% CI, 1.5-6.7) were at higher risk of IUD, compared with controls. MC pregnancies with ≥ 25% weight discordance were also at increased risk of NND (OR 4.66, 95% CI, 1.8-12.4) compared with those with concordant weight. The risk of IUD was higher when considering discordant pregnancies involving at least one SGA fetus. The overall risk of mortality in MC pregnancies was similar between the smaller and larger twin, except in those with BW discordance ≥ 20%.

CONCLUSION

DC and MC twin pregnancies discordant for fetal growth are at higher risk of IUD but not of NND compared with pregnancies with concordant BW. The risk of IUD in BW-discordant DC and MC twins is higher when at least one fetus is SGA. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Elective induction of labor at 39 weeks among nulliparous women: The impact on maternal and neonatal risk

Objective

Optimal management of pregnancies at 39 weeks gestational age is unknown. Therefore, we sought to perform a comparative effectiveness analysis of elective induction of labor (eIOL) at 39 weeks among nulliparous women with non-anomalous singleton, vertex fetuses as compared to expectant management (EM) which included IOL for medical or obstetric indications or at 41 weeks in undelivered mothers.

Materials and methods

A Monte Carlo micro-simulation model was constructed modeling two mutually exclusive health states: eIOL at 39 weeks, or EM with IOL for standard medical or obstetrical indications or at 41 weeks if undelivered. Health state distribution probabilities included maternal and perinatal outcomes and were informed by a review of the literature and data derived from the Consortium of Safe Labor. Analyses investigating preferences for maternal versus infant health were performed using weighted utilities. Primary outcome was determining which management strategy posed less maternal and neonatal risk. Secondary outcomes were rates of cesarean deliveries, maternal morbidity and mortality, stillbirth, neonatal morbidity and mortality, and preferences regarding the importance of maternal and perinatal health.

Results

A management strategy of eIOL at 39 weeks resulted in less maternal and neonatal risk as compared to EM with IOL at 41 weeks among undelivered patients. Cesarean section rates were higher in the EM arm (35.9% versus 13.9%, p<0.01). When analysis was performed only on patients with an unfavorable cervix, 39 week eIOL still resulted in fewer cesarean deliveries as compared to EM (8.0% versus 26.1%, p<0.01). There was no statistical difference in maternal mortality (eIOL 0% versus EM 0.01%, p = 0.32) but there was an increase in maternal morbidity among the EM arm (21.2% versus 16.5, p<0.01). There were more stillbirths (0.13% versus 0%, p<0.0003), neonatal deaths (0.25% versus 0.12%, p< 0.03), and neonatal morbidity (12.1% versus 9.4%, p<0.01) in the EM arm as compared to the eIOL arm. Preference modeling revealed that 39 week eIOL was favored over EM.

Conclusions and relevance

Mathematical modeling revealed that eIOL at 39 weeks resulted in lower population risks as compared to EM with induction of labor at 41 weeks. Specifically, eIOL at 39 weeks resulted in a lower cesarean section rate, lower rates of maternal morbidity, fewer stillbirths and neonatal deaths, and lower rates of neonatal morbidity.

Three-Dimensional Power Doppler Evaluation of Cerebral Vascular Blood Flow: A Novel Tool in the Assessment of Fetal Growth Restriction

OBJECTIVES

To determine whether fetuses with fetal growth restriction (FGR) are more likely to have abnormal cerebral vascular flow patterns compared to fetuses who are appropriate for gestational age (AGA) when quantified by using 3-dimensional (3D) power Doppler ultrasound.

METHODS

We conducted a prospective cohort study of singleton gestations presenting for growth ultrasound examination between 24 and 36 weeks' gestation. Patients with FGR (estimated fetal weight < 10th percentile) were enrolled and matched 1:1 for gestational age (±7 days) with AGA fetuses. A standardized 3D power Doppler image of the middle cerebral artery territory was obtained from each patient. The vascularization index (VI), flow index (FI), and vascularization-flow index (VFI) were calculated by the Virtual Organ computer-aided analysis technique (GE Healthcare, Milwaukee, WI). These indices were compared between FGR and AGA fetuses and correlated with 2-dimensional Doppler parameters. Neonatal outcomes were also compared with respect to the 3D parameters.

RESULTS

Of 306 patients, there were 151 cases of FGR. There was no difference in the VI (6.0 versus 5.7; P = .65) or VFI (2.0 versus 1.8; P = .31) between the groups; however, the FI was significantly higher in FGR fetuses compared to AGA controls (33.9 versus 32.3; P = .009). There was a weak, but significant, negative correlation between the FI and both the middle cerebral artery pulsatility index (r = -0.34; P < .001) and cerebroplacental ratio (r = -0.29; P < .001). Within the FGR group, there was no difference in any of the 3D vascular indices with regard to neonatal outcomes.

CONCLUSIONS

Three-dimensional power Doppler measurement of cerebral blood flow, but not the vascularization pattern, is significantly altered in FGR. This measurement may play a future role in distinguishing pathologic FGR from constitutionally small growth.

Acute Appendicitis in Pregnancy: Predictive Clinical Factors and Pregnancy Outcomes

Objective The objective of this study was to identify clinical factors predictive of appendicitis in pregnant women and associated obstetric outcomes. Study Design We performed a single-center, retrospective cohort study of pregnant women who underwent magnetic resonance imaging for suspected appendicitis from 2007 to 2012. Rates and odds of appendicitis based on presenting signs and symptoms were estimated. We also estimated rates and odds of adverse obstetric outcomes among women with a diagnosis of appendicitis. Results Of 171 pregnant women evaluated, 14 (8.2%) had pathology-confirmed appendicitis. White blood cell (WBC) count on admission was moderately predictive of appendicitis (area under the receiver operating characteristic curve, 0.74). A WBC count > 18,000 made the diagnosis of appendicitis more than 10 times more likely (adjusted odds ratio, 10.51; 95% confidence interval, 1.67-43.1). Of 127 women with complete pregnancy follow-up, women with appendicitis had a higher rate of pregnancy loss < 20 weeks (2/13 [15.4%] vs. 3/104 [2.9%], p < 0.01) and < 24 weeks (3/13 [23.1%] vs. 4/104 [3.8%]) than those without appendicitis. Appendicitis diagnosed in the first trimester was associated with increased risk of pregnancy loss < 24 weeks. Conclusion WBC count > 18,000 on admission is significantly associated with appendicitis in pregnant women undergoing evaluation for appendicitis. Appendicitis during the first trimester of pregnancy is associated with previable pregnancy loss.

A stillbirth calculator: Development and internal validation of a clinical prediction model to quantify stillbirth risk

Objective

To generate a clinical prediction tool for stillbirth that combines maternal risk factors to provide an evidence based approach for the identification of women who will benefit most from antenatal testing for stillbirth prevention.

Design

Retrospective cohort study

Setting

Midwestern United States quaternary referral center

Population

Singleton pregnancies undergoing second trimester anatomic survey from 1999–2009. Pregnancies with incomplete follow-up were excluded.

Methods

Candidate predictors were identified from the literature and univariate analysis. Backward stepwise logistic regression with statistical comparison of model discrimination, calibration and clinical performance was used to generate final models for the prediction of stillbirth. Internal validation was performed using bootstrapping with 1,000 repetitions. A stillbirth risk calculator and stillbirth risk score were developed for the prediction of stillbirth at or beyond 32 weeks excluding fetal anomalies and aneuploidy. Statistical and clinical cut-points were identified and the tools compared using the Integrated Discrimination Improvement.

Main outcome measures

Antepartum stillbirth

Results

64,173 women met inclusion criteria. The final stillbirth risk calculator and score included maternal age, black race, nulliparity, body mass index, smoking, chronic hypertension and pre-gestational diabetes. The stillbirth calculator and simple risk score demonstrated modest discrimination but clinically significant performance with no difference in overall performance between the tools [(AUC 0.66 95% CI 0.60–0.72) and (AUC 0.64 95% CI 0.58–0.70), (p = 0.25)].

Conclusion

A stillbirth risk score was developed incorporating maternal risk factors easily ascertained during prenatal care to determine an individual woman’s risk for stillbirth and provide an evidenced based approach to the initiation of antenatal testing for the prediction and prevention of stillbirth.

Advanced Maternal Age and the Risk of Major Congenital Anomalies

Objective This study aims to determine if advanced maternal age (AMA) is a risk factor for major congenital anomalies, in the absence of aneuploidy. Study Design Retrospective cohort study of all patients with a singleton gestation presenting for second trimester anatomic survey over a 19-year study period. Aneuploid fetuses were excluded. Study groups were defined by maternal age ≤ 34 and ≥ 35 years. The primary outcome was the presence of one or more major anomalies diagnosed at the second trimester ultrasound. Univariable and multivariable logistic regression analyses were used to estimate the risk of major anomalies in AMA patients. Results Of 76,156 euploid fetuses, 2.4% (n = 1,804) were diagnosed with a major anomaly. There was a significant decrease in the incidence of major fetal anomalies with increasing maternal age until the threshold of age 35 (p < 0.001). Being AMA was significantly associated with an overall decreased risk for major fetal anomalies (adjusted odds ratio: 0.59, 95% confidence interval: 0.52-0.66). The subgroup analysis demonstrated similar results for women ≥ 40 years of age. Conclusion AMA is associated with an overall decreased risk for major anomalies. These findings may suggest that the "all or nothing" phenomenon plays a more robust role in embryonic development with advancing oocyte age, with anatomically normal fetuses being more likely to survive.

Does adjunctive use of progesterone in women with cerclage improve prevention of preterm birth?. J Matern Fetal Neonatal Med 2017;31:202-208. [PMID: 28068860 DOI: 10.1080/14767058.2017.1280019]

OBJECTIVE

To evaluate outcomes among pregnancies with cerclage as compared to cerclage and adjunctive progesterone.

METHODS

A retrospective cohort study was performed from 1 October 2011-30 June 2015 including women with a singleton gestation with vaginal cerclage. Exclusion criteria included multiple gestations, simultaneous 17-alpha hydroxyprogesterone caproate (17-OHPC) and vaginal progesterone (vag-p) use, and patients lost to follow-up. Primary outcome was prevention of preterm birth less than 35 (PTB <35) weeks gestational age (GA).

RESULTS

One hundred thirty-six patients met inclusion criteria; 73 women had cerclage only, 53 had cerclage and 17-OHPC, 10 had cerclage and vag-p. GA at cerclage placement was similar across groups (p = 0.068). There was a difference in prevention of PTB <35 weeks GA among groups (p = 0.035) with a trend toward earlier delivery among patients with cerclage and vag-p. Rates of PTB <35 weeks in the cerclage (29%) and cerclage and 17-OHPC groups (34%) were similar (p = 0.533). The odds ratio for risk of PTB <35 weeks among women with cerclage and vag-p as compared to all other patients was 5.21 (95%CI: 1.3-21.2).

CONCLUSION

The combination of cerclage with intramuscular progesterone resulted in similar PTB prevention as compared to cerclage alone. There may be an association between cerclage, vaginal progesterone and higher rates of PTB which may be attributed to characteristics of the group rather than the therapies studied.

Gestational Weight Gain: Association with Adverse Pregnancy Outcomes

Background It is unclear how adherence to the Institute of Medicine's (IOM) guidelines for weight gain affects pregnancy outcomes. Objective We investigated how weight gain outside the IOM's recommendations affects the risks of adverse pregnancy outcomes. Study Design We performed a secondary analysis of a prospective cohort study including singleton, nonanomalous fetuses. The risks of small for gestational age (SGA), macrosomia, preeclampsia, cesarean delivery, gestational diabetes, or preterm birth were calculated for patients who gained weight below or above the IOM's recommendations based on body mass index category. A time-to-event analysis was performed to account for gestational age at delivery. A Cox proportional model was fit to estimate hazard ratios accounting for possible confounders. Results Women who gained weight below recommendations were 2.5 times more likely to deliver SGA and twice as likely to deliver preterm. Normal-weight patients who gained below recommendations were 2.5 times more likely to deliver SGA and twice as likely to deliver preterm. Obese patients who gained inadequate weight were 2.5 times more likely to deliver SGA. Conclusion Among normal-weight patients, adhering to IOM recommendations may prevent growth abnormalities and preterm delivery. Among obese patients, a minimum weight gain requirement may prevent SGA infants.

Cost-Effectiveness of Old and New Technologies for Aneuploidy Screening

Cost-effectiveness analyses allow assessment of whether marginal gains from new technology are worth increased costs. Several studies have examined cost-effectiveness of Down syndrome (DS) screening and found it to be cost-effective. Noninvasive prenatal screening also appears to be cost-effective among high-risk women with respect to DS screening, but not for the general population. Chromosomal microarray (CMA) is a genetic sequencing method superior to but more expensive than karyotype. In light of CMAs greater ability to detect genetic abnormalities, it is cost-effective when used for prenatal diagnosis of an anomalous fetus. This article covers methodology and salient issues of cost-effectiveness.

A Randomized Trial Comparing Skin Antiseptic Agents at Cesarean Delivery

BACKGROUND

Preoperative skin antisepsis has the potential to decrease the risk of surgical-site infection. However, evidence is limited to guide the choice of antiseptic agent at cesarean delivery, which is the most common major surgical procedure among women in the United States.

METHODS

In this single-center, randomized, controlled trial, we evaluated whether the use of chlorhexidine-alcohol for preoperative skin antisepsis was superior to the use of iodine-alcohol for the prevention of surgical-site infection after cesarean delivery. We randomly assigned patients undergoing cesarean delivery to skin preparation with either chlorhexidine-alcohol or iodine-alcohol. The primary outcome was superficial or deep surgical-site infection within 30 days after cesarean delivery, on the basis of definitions from the Centers for Disease Control and Prevention.

RESULTS

From September 2011 through June 2015, a total of 1147 patients were enrolled; 572 patients were assigned to chlorhexidine-alcohol and 575 to iodine-alcohol. In an intention-to-treat analysis, surgical-site infection was diagnosed in 23 patients (4.0%) in the chlorhexidine-alcohol group and in 42 (7.3%) in the iodine-alcohol group (relative risk, 0.55; 95% confidence interval, 0.34 to 0.90; P=0.02). The rate of superficial surgical-site infection was 3.0% in the chlorhexidine-alcohol group and 4.9% in the iodine-alcohol group (P=0.10); the rate of deep infection was 1.0% and 2.4%, respectively (P=0.07). The frequency of adverse skin reactions was similar in the two groups.

CONCLUSIONS

The use of chlorhexidine-alcohol for preoperative skin antisepsis resulted in a significantly lower risk of surgical-site infection after cesarean delivery than did the use of iodine-alcohol. (Funded by the National Institutes of Health and Washington University School of Medicine in St. Louis; ClinicalTrials.gov number, NCT01472549.).