Rodney K. Edwards

Mode of delivery in women with class III obesity: planned cesarean compared with induction of labor

OBJECTIVEnTo compare maternal and neonatal outcomes between planned cesarean delivery and induction of labor in women with class III obesity (body mass index ≥40 kg/m(2)).nnnSTUDY DESIGNnIn this retrospective cohort study, we identified all women with a body mass index ≥40 kg/m(2) who delivered a singleton at our institution from January 2007 to February 2013 via planned cesarean or induction of labor (regardless of eventual delivery route) at 37-41 weeks. Patients in spontaneous labor were excluded. The primary outcome was a composite of maternal morbidity including death as well as operative, infection, and thromboembolic complications. The secondary outcome was a neonatal morbidity composite. Additional outcomes included individual components of the composites. Student t, χ(2), and Fisher exact tests were used for statistical analysis. To calculate adjusted odds ratios, covariates were analyzed via multivariable logistic regression.nnnRESULTSnThere are 661 mother-infant pairs that met enrollment criteria-399 inductions and 262 cesareans. Groups were similar in terms of prepregnancy weight, pregnancy weight gain, and delivery body mass index. Of the 399 inductions, 258 had cervical ripening (64.7%) and 163 (40.9%) had a cesarean delivery. After multivariable adjustments, there was no significant difference in the maternal morbidity composite (adjusted odds ratio, 0.98; 95% confidence interval, 0.55-1.77) or in the neonatal morbidity composite (adjusted odds ratio, 0.81; 95% confidence interval, 0.37-1.77) between the induction and cesarean groups.nnnCONCLUSIONnIn term pregnant women with class III obesity, planned cesarean does not appear to reduce maternal and neonatal morbidity compared with induction of labor.

Trisomy 18: A single-center evaluation of management trends and experience with aggressive obstetric or neonatal intervention.

We conducted a retrospective cohort study including all prenatal and postnatal diagnoses of trisomy 18 (T18) from 2004 to 2014 at a single tertiary referral center in the southern United States to evaluate the natural history and perinatal outcomes associated with T18 over the past decade. We analyzed pregnancy outcome, mode of delivery, and for live‐births, the number and types of neonatal interventions, and characterized interventions as aggressive or non‐aggressive. Survival analyses were conducted based on mode of delivery and aggressive compared to non‐aggressive interventions. A total of 167 cases of T18 were identified, 150 with available records. There were 141 (94.0%) with full T18; the remainder had mosaicism (1.3%), a translocation (0.7%), or an isochromosome 18 (4.0%). Most diagnoses were prenatal (73.3%, nu2009=u2009110). Of the 150 patients, there were 54 live births: 21 (38.9%) delivered vaginally, 32 (59.3%) delivered by cesarean, and mode of delivery could not be ascertained for one. Median duration of survival was 12 days (interquartile range 3–90 days). Over time, there were no changes toward increased intervention (obstetric or neonatal). For the 49 neonates who received some intervention, there was no significant difference in survival time between neonates receiving aggressive (nu2009=u200936, median survival 24 days, interquartile range 6–247) and non‐aggressive (nu2009=u200913, median survival 30 days, interquartile range 8–148) intervention (Pu2009=u20090.90). There was similarly no difference in neonatal survival based on mode of delivery (Pu2009=u20090.79). Survival of infants with T18 is not improved with aggressive obstetric or neonatal care.

The association of maternal obesity with fetal pH and base deficit at cesarean delivery.

OBJECTIVE: To evaluate the association between maternal body mass index (BMI) and umbilical cord acid-base status at the time of cesarean delivery. METHODS: We conducted a retrospective multicenter cohort study using data from the Cesarean Section Registry of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network. Women were included if they delivered a live, nonanomalous singleton at 37–41 weeks of gestation by prelabor cesarean under spinal anesthesia. We excluded women with diagnoses that might be associated with uteroplacental insufficiency. Body mass index at delivery was examined both as a continuous and categorical exposure, and acid-base status was based on cord arterial pH and base deficit. RESULTS: There were 5,742 mother–neonate pairs who met criteria for analysis. Among possible confounders (including sociodemographic variables, number of previous uterine incisions, diabetes, hematocrit, neonatal gender, and birth weight), African American race, birth weight, parity, and smoking status were significantly associated with both BMI and acid-base parameters. Adjusted for those four factors, with increasing BMI category (less than 25, 25–29.9, 30–34.9, 35–39.9, and 40 or higher), mean pH decreased from 7.25 to 7.22 (P<.001), proportion with pH less than 7.1 increased from 3.5% to 7.7% (P=.011), mean base deficit increased from 4.01 mmol/L to 4.83 mmol/L (P=.030), and proportion with base deficit of 12 mmol/L or more increased from 0.6% to 4.7% (P=.003). When BMI was analyzed continuously and adjusted for these confounders, for every 10-unit increase in BMI, cord arterial pH decreased by 0.01 (P<.001) and base deficit increased by 0.26 mmol/L (P=.005). CONCLUSION: For women undergoing nonemergent prelabor cesarean delivery under spinal anesthesia, fetal pH declines and base deficit rises as maternal BMI increases. LEVEL OF EVIDENCE: II

Predicting fetal acidemia using umbilical venous cord gas parameters

OBJECTIVE: To assess the utility of umbilical cord venous blood gas measures for prediction of umbilical artery pH and base deficit acidemia. METHODS: A retrospective cohort study was conducted of all singletons with valid paired arterial and venous cord gas samples delivered at our institution from January 2006 to March 2012. Fetal acidemia was defined primarily as cord arterial blood gas pH less than 7.0. We also evaluated prediction of acidemia, defined as an arterial base deficit 12 mmol/L or greater. Logistic regression was performed to estimate probabilities of fetal arterial pH and base deficit acidemia given venous blood gas pH or base deficit. Receiver operating characteristic curves were derived to determine predictive ability. Venous blood gas pH and base deficit cutoffs associated with 1% or less, 5%, 10%, and 50% probability of fetal acidemia were identified. RESULTS: Of 23,506 births, 11,455 (49%) met criteria for inclusion. The frequency of arterial blood gas pH less than 7.0 was 127 (1.1%); arterial blood gas base deficit 12 mmol/L or greater was 245 (2.1%). Venous blood gas pH (area under the curve [AUC] 0.949, 95% confidence interval [CI] 0.920–0.979; P<.001) and base deficit (AUC 0.969, 95% CI 0.954–0.983; P<.001) were predictors of acidemia based on arterial blood gas pH and base deficit, respectively. Venous blood gas pH cutoffs associated with 1% or less, 5%, or 10% probabilities of arterial blood gas pH less than 7.0 were 7.23, 7.17, and 7.14, respectively. Venous blood gas base deficit values associated with similar probabilities for base deficit 12 mmol/L or greater were 6.3 or less, 8.2 or less, and 9.0 mmol/L or less. For prediction of arterial blood gas pH, adjusting venous blood gas pH for base deficit increased the AUC (0.961, 95% CI 0.938–0.984). Prediction of arterial blood gas base deficit by venous blood gas base deficit was unchanged by adjustment for pH (AUC 0.969, 95% CI 0.955–0.984). CONCLUSION: We demonstrate that venous blood gas parameters are powerful predictors of arterial blood gas pH and base deficit and can be used to predict the likelihood of fetal acidemia when the cord arterial blood gas is not available. LEVEL OF EVIDENCE: II

Revisiting the cost-effectiveness of universal cervical length screening: importance of progesterone efficacy

BACKGROUNDnPreterm birth (PTB) is a significant cause of neonatal morbidity and mortality. Studies have shown that vaginal progesterone therapy for women diagnosed with shortened cervical length can reduce the risk of PTB. However, published cost-effectiveness analyses of vaginal progesterone for short cervix have not considered an appropriate range of clinically important parameters.nnnOBJECTIVEnTo evaluate the cost-effectiveness of universal cervical length screening in women without a history of spontaneous PTB, assuming that all women with shortened cervical length receive progesterone to reduce the likelihood of PTB.nnnSTUDY DESIGNnA decision analysis model was developed to compare universal screening and no-screening strategies. The primary outcome was the cost-effectiveness ratio of both the strategies, defined as the estimated patient cost per quality-adjusted life-year (QALY) realized by thexa0children. One-way sensitivity analyses were performed by varying progesterone efficacy to prevent PTB. A probabilistic sensitivity analysis was performed to address uncertainties in model parameter estimates.nnnRESULTSnIn our base-case analysis, assuming that progesterone reduces the likelihood of PTB by 11%, the incremental cost-effectiveness ratio for screening was

Survey of American obstetricians regarding group B streptococcus: opinions and practice patterns

158,000/QALY. Sensitivity analyses show that these results are highly sensitive to the presumed efficacy of progesterone to prevent PTB. In a 1-way sensitivity analysis, screening results in cost-saving if progesterone can reduce PTB by 36%. Additionally, for screening to be cost-effective at WTP=

Nulliparous Women in the Second Stage of Labor: Changes in Delivery Outcomes Between Two Cohorts From 2000 and 2011.

60,000 in three clinical scenarios, progesterone therapy has to reduce PTB by 60%, 34% and 93%. Screening is never cost-saving in the worst-case scenario or when serial ultrasounds are employed, but could be cost-saving with a two-day hospitalization only if progesterone were 64% effective.nnnCONCLUSIONnCervical length screening and treatment with progesterone is a not a dominant, cost-effective strategy unless progesterone is more effective than has been suggested by available data for US women. Until future trials demonstrate greater progesterone efficacy, and effectiveness studies confirm a benefit from screening and treatment, the cost-effectiveness of universal cervical length screening in the United States remains questionable.

Vaginal Microbiota in Pregnancy: Evaluation Based on Vaginal Flora, Birth Outcome, and Race

OBJECTIVEnThe objective of the study was to evaluate attitudes and practice patterns of obstetricians related to screening for group B streptococcal colonization and providing intrapartum antibiotic prophylaxis against early-onset neonatal infections with group B streptococcus.nnnSTUDY DESIGNnWe mailed a survey to 546 members of the American College of Obstetricians and Gynecologists, including members of the Collaborative Ambulatory Research Network and non-Collaborative Ambulatory Research Network members. Stratified random selection was used to generate samples from both of these groups.nnnRESULTSnThe survey response rate was 60% for Collaborative Ambulatory Research Network members and 42% for non-Collaborative Ambulatory Research Network members. Of the 206 respondents who reported providing prenatal care, 97% collect screening samples at 35-37 weeks gestational age. Anatomic sites used to collect samples were more variable: 62% include lower vagina and rectum, 26% include lower vagina and perianal skin but not rectum, and 5% include neither the perianal skin nor the rectum. First-line agents for intrapartum antibiotic prophylaxis were penicillin (71%), ampicillin (27%), and cefazolin (2%). For patients reporting a nonanaphylactic penicillin allergy, drugs used for intrapartum antibiotic prophylaxis were more varied: cefazolin (51%), clindamycin (36%), vancomycin (8%), and erythromycin (5%). For patients undergoing a labor induction starting with a cervical ripening agent, less than 40% typically give the first dose of intrapartum antibiotic prophylaxis before or at the time of cervical ripening agent administration, and 15% wait until the patient reaches the active phase of labor.nnnCONCLUSIONnGaps in knowledge and reported practice related to the prevention of early-onset neonatal group B streptococcus infections were similar to gaps in implementation of guidelines demonstrated in past studies. New approaches to improve implementation are warranted.

The Problem of the Pannus: Physician Preference Survey and a Review of the Literature on Cesarean Skin Incision in Morbidly Obese Women.

OBJECTIVE: To evaluate changes over the past decade in the mode of delivery and second-stage duration in nulliparous women. METHODS: We conducted a retrospective cohort study at a single institution of nulliparous women reaching complete cervical dilation with singleton gestations 36 weeks or greater from January 1, 2011, to December 31, 2012, and compared these with a prior cohort prospectively collected from July 28, 2000, to February 28, 2003. We excluded pregnancies with prenatally diagnosed fetal anomalies. The primary outcome was cesarean delivery. Secondary outcomes included second-stage duration, rates of operative vaginal delivery (forceps and vacuum collectively), and indications for cesarean delivery and operative vaginal delivery. RESULTS: There were 1,023 mother–neonate pairs in the prior cohort and 1,476 in the current cohort. In the prior and current cohorts, respectively, 2% compared with 6% underwent cesarean delivery, 21% compared with 10% underwent operative vaginal delivery, and 77% compared with 84% had spontaneous vaginal delivery (all P<.01). Compared with the prior cohort, the adjusted odds (OR) of cesarean delivery (compared with any vaginal birth) for current patients was 1.74 (95% confidence interval [CI] 1.04–2.91), and in a separate regression model, the adjusted OR of operative vaginal delivery (compared with spontaneous vaginal delivery or cesarean delivery) was 0.42 (95% CI 0.33–0.54). Median (25th, 75th percentile) second-stage duration significantly increased from 38 (20, 71) to 42 (22, 87) minutes (P<.01), but this difference was nullified after adjusting for confounders. CONCLUSION: Comparing cohorts from 2000 and 2011, although the second-stage duration has not changed appreciably, nulliparous women in the second stage of labor at our institution are twice as likely to undergo cesarean delivery and half as likely to undergo operative vaginal delivery. LEVEL OF EVIDENCE: II

Effect of hydration on spontaneous labor outcomes in nulliparous pregnant women: a multicenter randomized controlled trial comparing three methods.

OBJECTIVEnThis study aims to evaluate vaginal microbiota differences by bacterial vaginosis (BV), birth timing, and race, and to estimate parameters to power future vaginal microbiome studies.nnnMETHODSnPreviously, vaginal swabs were collected at 21 to 25 weeks (stored at -80°C), and vaginal smears evaluated for BV (Nugent criteria). In a blinded fashion, 40 samples were selected, creating 8 equal-sized groups stratified by race (black/white), BV (present/absent), and birth timing (preterm/term). Samples were thawed, DNA extracted, and prepared. Polymerase chain reaction (PCR) with primers targeting the 16S rDNA V4 region was used to prepare an amplicon library. PCR products were sequenced and analyzed using quantitative insight into microbial ecology; taxonomy was assigned using ribosomal database program classifier (threshold 0.8) against the modified Greengenes database.nnnRESULTSnAfter quality control, 97,720 sequences (mean) per sample, single-end 250 base-reads, were analyzed. BV samples had greater microbiota diversity (pu2009<u20090.05)-with BVAB1, Prevotella, and unclassified genus, Bifidobacteriaceae family (all pu2009<u20090.001) more abundant; there was minimal content of Gardnerella or Mobiluncus. Microbiota did not differ by race or birth timing, but there was an association between certain microbial clusters and preterm birth (pu2009=u20090.07). To evaluate this difference, 159 patients per group are needed.nnnCONCLUSIONSnThere are differences in the vaginal microbiota between patients with and without BV. Larger studies should assess the relationship between microbiota composition and preterm birth.