Intrapartum ultrasound measurement of angle of progression at the onset of the second stage of labor for prediction of spontaneous vaginal delivery in term singleton pregnancies: a systematic review and meta-analysis

OBJECTIVE

This study aimed to investigate the diagnostic performance of transperineal ultrasound-measured angles of progression at the onset of the second stage of labor for the prediction of spontaneous vaginal delivery in singleton term pregnancies with cephalic presentation.

DATA SOURCES

We performed a predefined systematic search in PubMed, Embase, Scopus, Web of Science, and Google Scholar from inception to February 5, 2021.

STUDY ELIGIBILITY CRITERIA

Prospective cohort studies that evaluated the diagnostic performance of transperineal ultrasound-measured angles of progression (index test) at the onset of the second stage of labor (ie, when complete cervical dilation is diagnosed) for the prediction of spontaneous vaginal delivery (reference standard) were eligible for inclusion. Eligible studies were limited to those published as full-text articles in the English language and those that included only parturients with a singleton healthy fetus at term with cephalic presentation.

STUDY APPRAISAL AND SYNTHESIS METHODS

Study quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 tool. Summary receiver operating characteristic curves, pooled sensitivities and specificities, area under the curve, and summary likelihood ratios were calculated using the Stata software. Subgroup analyses were done based on angle of progression ranges of 108° to 119°, 120° to 140°, and 141° to 153°.

RESULTS

A total of 8 studies reporting on 887 pregnancies were included. Summary estimates of the sensitivity and specificity of transperineal ultrasound-measured angle of progression at the onset of the second stage of labor for predicting spontaneous vaginal delivery were 94% (95% confidence interval, 88%-97%) and 47% (95% confidence interval, 18%-78%), respectively, for an angle of progression of 108° to 119°, 81% (95% confidence interval, 70%-89%) and 73% (95% confidence interval, 57%-85%), respectively, for an angle of progression of 120° to 140°, and 66% (95% confidence interval, 56%-74%) and 82% (95% confidence interval, 66%-92%), respectively, for an angle of progression of 141° to 153°. Likelihood ratio syntheses gave overall positive likelihood ratios of 1.8 (95% confidence interval, 1-3.3), 3 (95% confidence interval, 2-4.7), and 3.7 (95% confidence interval, 1.7-8.1) and negative likelihood ratios of 0.13 (95% confidence interval, 0.07-0.22), 0.26 (95% confidence interval, 0.18-0.38), and 0.42 (95% confidence interval, 0.29-0.60) for angle of progression ranges of 108° to 119°, 120° to 140°, and 141° to 153°, respectively.

CONCLUSION

Angle of progression measured by transperineal ultrasound at the onset of the second stage of labor may predict spontaneous vaginal delivery in singleton, term, cephalic presenting pregnancies and has the potential to be used along with physical examinations and other clinical factors in the management of labor and delivery.

Intravenous labetalol versus oral nifedipine for acute hypertension in pregnancy: effects on cerebral perfusion pressure

BACKGROUND

Pregnant women with preeclampsia have been found to have elevated cerebral perfusion pressure and impaired cerebral autoregulation compared with normal pregnant women. Transcranial Doppler is a noninvasive technique used to estimate cerebral perfusion pressure. The effects of different antihypertensive medications on cerebral perfusion pressure in preeclampsia are unknown.

OBJECTIVE

To compare the change in cerebral perfusion pressure before and after intravenous labetalol vs oral nifedipine in the setting of acute severe hypertension in pregnancy.

STUDY DESIGN

This is a prospective cohort study of pregnant women between 24 and 42 weeks' gestation with severe hypertension (systolic blood pressure ≥160 mm Hg and/or diastolic blood pressure ≥110 mm Hg). Women who consented to the study and received either intravenous labetalol or oral nifedipine were included. Exclusion criteria included active labor or receipt of any antihypertensive medication within 2 hours of initial cerebral perfusion pressure measurement. Peripheral blood pressure and transcranial Doppler studies for middle cerebral artery hemodynamics were performed prior to the administration of antihypertensive medications and repeated 30 minutes after medication administration.

RESULTS

A total of 16 women with acute severe hypertension were enrolled; 8 received intravenous labetalol and 8 received oral nifedipine. There were no significant differences between the labetalol and nifedipine groups in baseline characteristics such as maternal age, race and ethnicity, payment, hospital site, body mass index, nulliparity, gestational age, preexisting diabetes mellitus or chronic hypertension, fetal growth restriction, magnesium sulfate administration, and symptomatology (P>.05). When examined 30 minutes after the administration of either intravenous labetalol or oral nifedipine, there was a significantly greater decrease in systolic blood pressure (-9.8 mm Hg vs -39 mm Hg; P=.003), mean arterial pressure (-7.1 mm Hg vs -22.3 mm Hg; P=.02), and cerebral perfusion pressure (-2.5 mm Hg vs -27.7 mm Hg; P=.01) in the nifedipine group. There was no statistically significant decrease in diastolic blood pressure (-12.9 mm Hg vs -5.4 mm Hg; P=.15). The change in middle cerebral artery velocity by transcranial Doppler was compared between the groups and was not different (0.07 cm/s vs 0.16 cm/s; P=.64).

CONCLUSION

Oral nifedipine resulted in a significant decrease in cerebral perfusion pressure, whereas labetalol did not, after administration for acute severe hypertension among women with preeclampsia. This decrease seems to be driven by a decrease in peripheral arterial blood pressure rather than a direct change in cerebral blood flow.

Low-dose aspirin for preeclampsia prevention: efficacy by ethnicity and race

BACKGROUND

Low-dose aspirin is recommended for the prevention of preeclampsia among women at a high risk of developing the disease. Aspirin undergoes polymorphic metabolism, and it is well known that common genetic polymorphisms are related to aspirin intolerance. We hypothesized that the efficacy of aspirin prophylaxis may differ by ethnicity and race.

OBJECTIVE

This study aimed to compare the rates of preeclampsia among low- and high-risk women who received aspirin compared with placebo, stratifying results by ethnicity and race as a first-pass approximation of genomic polymorphisms.

STUDY DESIGN

This is a secondary analysis of 2 randomized controlled trials previously performed by the Maternal-Fetal Medicine Units Network: the Low-Risk Aspirin trial and the High-Risk Aspirin trial. For the Low-Risk Aspirin trial, normotensive, nulliparous women were enrolled between 13 and 26 weeks' gestation and randomized to 60 mg aspirin daily or placebo. For the High-Risk Aspirin trial, women with pregestational insulin-treated diabetes mellitus, chronic hypertension, multiple gestations, or a history of preeclampsia in a previous pregnancy were enrolled between 13 and 26 weeks' gestation and randomized to 60 mg aspirin daily or placebo. The primary outcome of our secondary analysis was preeclampsia. Secondary outcomes included gestational age at delivery, preterm delivery, placental abruption, small for gestational age, stillbirth, and neonatal death. Outcomes were stratified by ethnicity and race (Hispanic, non-Hispanic white, non-Hispanic black, or other).

RESULTS

In the Low-Risk Aspirin trial of 3135 women, the risk of preeclampsia was significantly reduced among non-Hispanic white women who received aspirin compared with non-Hispanic white women who received placebo (relative risk, 0.19; 95% confidence interval, 0.06-0.63; P=.007). The risk of preeclampsia was not different when comparing the aspirin and placebo groups among the Hispanic, non-Hispanic black, or other ethnicity and race groups. The efficacy among non-Hispanic white women persisted after consideration of compliance and gestational age at randomization (relative risk, 0.07; 95% confidence interval, 0.009-0.51; P=.009). As noted in the original trial, there was an increased risk of placental abruption in the aspirin group overall compared with placebo (P=.025). The risk of stillbirth was significantly increased among non-Hispanic black women who received aspirin compared with non-Hispanic black women who received placebo (P=.048). In the High-Risk Aspirin trial of 2539 women, 269 were Hispanic (10.6%), 832 were non-Hispanic white (32.8%), 1426 were non-Hispanic black (56.2%), and 12 were categorized as other (0.5%). Stratification by ethnicity and race did not reveal a decreased incidence of preeclampsia for any of the subgroups (P>.05). Moreover, there was no significant difference in other measured outcomes including preterm delivery at <37 weeks' gestation, placental abruption, small for gestational age, stillbirth, or neonatal death.

CONCLUSION

The incidence of preeclampsia was significantly reduced among low-risk non-Hispanic white women who received aspirin compared with placebo (P=.007), but not overall or among Hispanic or non-Hispanic black women. The analysis of high-risk women did not indicate a difference in the efficacy of aspirin by ethnicity and race.

Chlorhexidine-Alcohol Compared with Povidone-Iodine Preoperative Skin Antisepsis for Cesarean Delivery: A Systematic Review and Meta-Analysis

OBJECTIVE

To compare chlorhexidine-alcohol with povidone-iodine solutions for skin antisepsis prior to cesarean delivery for the prevention of surgical site infection.

STUDY DESIGN

Electronic databases MEDLINE, Embase, Scopus, and Clinicaltrials.gov were searched from inception to August 2017. Eligible studies included randomized controlled trials comparing chlorhexidine-alcohol with povidone-iodine skin preparation solutions for women undergoing cesarean delivery. The primary outcome was surgical site infection including superficial or deep wound infection. Meta-analysis was performed, and risk ratios (RRs) with 95% confidence interval (CI) were calculated using the Mantel-Haenszel random effects model. Statistical heterogeneity was assessed using Higgin's I ².

RESULTS

Of 61 abstracts identified in the primary search, four studies (3,059 women) met the eligibility criteria. The risk of surgical site infection was significantly reduced with chlorhexidine-alcohol (RR: 0.72; 95% CI: 0.52-0.98). No heterogeneity across studies was observed with I ² = 0%. Subgroup analysis of superficial infection only or deep infection only showed no statistically significant difference (RR: 0.76, 95% CI: 0.54-1.08; and RR: 0.50, 95% CI: 0.23-1.10, respectively).

CONCLUSION

Preoperative skin cleansing prior to cesarean delivery with chlorhexidine-alcohol reduces surgical site infection as compared with povidone-iodine solutions.

Clinical Impact of a Restrictive Labor Induction Approval Process

BACKGROUND/AIMS

The aim of this study was to evaluate the impact of a restrictive labor induction approval process on induction and primary cesarean delivery rates.

METHODS

A retrospective cohort study was conducted at a tertiary care academic center from 2006 through 2012. The cohort of deliveries before (pre-intervention) and after (post-intervention) the process included term, singleton pregnancies with no contraindication to vaginal delivery. The primary outcome was induction of labor rates, subgrouped on the basis of whether it was medically or nonmedically indicated. Secondary outcomes included the primary cesarean rate and other maternal and neonatal outcomes.

RESULTS

Of 13,753 deliveries, 6,746 met study inclusion criteria. There was a significant decrease in induction rates comparing the pre- and post-intervention periods (21.0 vs. 18.5%, p = 0.01). Nonmedically indicated induction rates also decreased significantly (2.9 vs. 0.6%, p < 0.001). No difference was observed in medically indicated induction (18.1 vs. 17.9%, p = 0.84), the primary cesarean rate (14.4 vs. 15.8%, p = 0.12), or any of the measured neonatal outcomes (p > 0.05).

CONCLUSIONS

Implementation of a labor induction approval process was associated with a significant reduction in overall and non-indicated induction rates but did not affect the primary cesarean rate or neonatal outcomes.

Neurological outcomes by mode of delivery for fetuses with open neural tube defects: a systematic review and meta-analysis

BACKGROUND

Controversy exists regarding the optimal mode of delivery for fetuses with open neural tube defects.

OBJECTIVE

To compare neurological outcomes among infants with open neural tube defects who underwent vaginal compared with caesarean delivery.

SEARCH STRATEGY

Electronic databases MEDLINE, EMBASE, Scopus, and Clinicaltrials.gov were searched from inception to November 2017.

SELECTION CRITERIA

Eligible studies included observational or randomised studies comparing vaginal and caesarean delivery in pregnancies with fetal open neural tube defects who did not undergo prenatal repair.

DATA COLLECTION AND ANALYSIS

Two reviewers independently reviewed abstracts and full-text articles. Outcomes were compared between vaginal and caesarean delivery and prelabour caesarean versus exposure to labour. The primary outcome was motor-anatomic level difference. Secondary outcomes included shunt requirement, sac disruption, meningitis, and ambulation at 2 years. Meta-analysis was performed and mean difference or odds ratios with 95% CI were calculated.

MAIN RESULTS

Of 201 abstracts identified in the primary search, nine studies (672 women) met the eligibility criteria. Comparing vaginal and caesarean delivery, there was no significant difference in motor-anatomic level difference (mean difference -0.10, 95% CI -0.58 to 0.38; I²  = 57%). The vaginal delivery group was less likely to require a shunt or have sac disruption [odds ratio (OR) 0.37, 95% CI 0.14-0.95 and OR 0.46, 95% CI 0.23-0.90, respectively]. Comparisons by prelabour caesarean versus exposure to labour showed no significant difference in motor-anatomic level difference (OR 1.29, 95% CI 0.63-3.21) or ambulation at 2 years (OR 2.13, 95% CI 0.35-13.12).

CONCLUSION

Caesarean delivery was not associated with improved neurological outcomes among fetuses with open neural tube defects.

TWEETABLE ABSTRACT

Available evidence does not support routine caesarean delivery for fetuses with open neural tube defects.

Standardizing Second-Trimester Medical Termination: Effects on Clinical Outcomes

OBJECTIVE

The objective of this study was to evaluate length of induction and postdelivery complications before and after implementation of a standardized approach to second-trimester medical termination of pregnancy.

STUDY DESIGN

This was a retrospective cohort study of all women undergoing medical termination of pregnancy between 13^0/7 and 26^6/7 weeks of gestation at a single, academic institution from July 1, 2012, through June 30, 2015. The primary outcome was the time from the start of induction of labor to delivery of the fetus. Postdelivery complications including the need for dilation and curettage (D&C), blood transfusion, and readmission to the hospital were secondary outcomes of interest.

RESULTS

A total of 62 women met inclusion criteria; 38 before and 24 after the intervention. There were no differences in measured baseline characteristics (p > 0.05). There was a significant decrease in induction time after the intervention (12.3 compared with 8.6 hours, p = 0.031). There was no significant difference in rates of D&C or other measured complications (p > 0.05).

CONCLUSION

Implementation of a standardized clinical guideline for second-trimester medical termination was associated with a decrease in length of induction. There was no significant difference in need for D&C or postdelivery complications; however, we were underpowered for these secondary outcomes.

Intrapartum factors associated with neonatal hypoxic ischemic encephalopathy: a case-controlled study

BACKGROUND

Neonatal encephalopathy (NE) affects 2-4/1000 live births with outcomes ranging from negligible neurological deficits to severe neuromuscular dysfunction, cerebral palsy and death. Hypoxic ischemic encephalopathy (HIE) is the sub cohort of NE that appears to be driven by intrapartum events. Our objective was to identify antepartum and intrapartum factors associated with the development of neonatal HIE.

METHODS

Hospital databases were searched using relevant diagnosis codes to identify infants with neonatal encephalopathy. Cases were infants with encephalopathy and evidence of intrapartum hypoxia. For each hypoxic ischemic encephalopathy case, four controls were randomly selected from all deliveries that occurred within 6 months of the case.

RESULTS

Twenty-six cases met criteria for hypoxic ischemic encephalopathy between 2002 and 2014. In multivariate analysis, meconium-stained amniotic fluid (aOR 12.4, 95% CI 2.1-144.8, p = 0.002), prolonged second stage of labor (aOR 9.5, 95% CI 1.0-135.3, p = 0.042), and the occurrence of a sentinel or acute event (aOR 74.9, 95% CI 11.9-infinity, p < 0.001) were significantly associated with hypoxic ischemic encephalopathy. The presence of a category 3 fetal heart rate tracing in any of the four 15-min segments during the hour prior to delivery (28.0% versus 4.0%, p = 0.002) was more common among hypoxic ischemic encephalopathy cases.

CONCLUSION

Prolonged second stage of labor and the presence of meconium-stained amniotic fluid are risk factors for the development of HIE. Close scrutiny should be paid to labors that develop these features especially in the presence of an abnormal fetal heart tracing. Acute events also account for a substantial number of HIE cases and health systems should develop programs that can optimize the response to these emergencies.

Impact of USPSTF recommendations for aspirin for prevention of recurrent preeclampsia

BACKGROUND

The US Preventive Services Task Force recommends low-dose aspirin for the prevention of preeclampsia among women at high risk for primary occurrence or recurrence of disease. Recommendations for the use of aspirin for preeclampsia prevention were issued by the US Preventive Services Task Force in September 2014.

OBJECTIVES

The objective of the study was to evaluate the incidence of recurrent preeclampsia in our cohort before and after the US Preventive Services Task Force recommendation for aspirin for preeclampsia prevention.

STUDY DESIGN

This was a retrospective cohort study designed to evaluate the rates of recurrent preeclampsia among women with a history of preeclampsia. We utilized a 2-hospital, single academic institution database from August 2011 through June 2016. We excluded multiple gestations and included only the first delivery for women with multiple deliveries during the study period. The cohort of women with a history of preeclampsia were divided into 2 groups, before and after the release of the US Preventive Services Task Force 2014 recommendations. Potential confounders were accounted for in multivariate analyses, and relative risk and adjusted relative risk were calculated.

RESULTS

A total of 17,256 deliveries occurred during the study period. A total of 417 women had a documented history of prior preeclampsia: 284 women before and 133 women after the US Preventive Services Task Force recommendation. Comparing the before and after groups, the proportion of Hispanic women in the after group was lower and the method of payment differed between the groups (P <.0001). The prevalence of type 1 diabetes was increased in the after period, but overall rates of pregestational diabetes were similar (6.3% before vs 5.3% after [P > .05]). Risk factors for recurrent preeclampsia included maternal age >35 years (relative risk, 1.83; 95% confidence interval, 1.34-2.48), Medicaid insurance (relative risk, 2.08; 95% confidence interval, 1.15-3.78), type 2 diabetes (relative risk, 2.13; 95% confidence interval, 1.37-3.33), and chronic hypertension (relative risk, 1.96; 95% confidence interval, 1.44-2.66). The risk of recurrent preeclampsia was decreased by 30% in the after group (adjusted relative risk, 0.70; 95% confidence interval, 0.52-0.95).

CONCLUSION

Rates of recurrent preeclampsia among women with a history of preeclampsia decreased by 30% after release of the US Preventive Services Task Force recommendation for aspirin for preeclampsia prevention. Future prospective studies should include direct measures of aspirin compliance, gestational age at initiation, and explore the influence of race and ethnicity on the efficacy of this primary prevention.

Do not throw the baby out with the bath water: a guide for using non-significant results in practice

Acting on results that are not statistically significant is challenging for clinicians. Such results are often interpreted as evidence of lack of association or as useless evidence. We provide a framework for interpreting and applying non-significant results at the point of care using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

Impact of a labor and delivery safety bundle on a modified adverse outcomes index

BACKGROUND

The Obstetrics Adverse Outcomes Index was designed to measure the quality of perinatal care and includes 10 adverse events that may occur at or around the time of delivery. We hypothesized that adverse outcomes in the labor and delivery suite, including hypoxic ischemic encephalopathy, could be decreased with a combination of interventions, even among high-risk pregnancies.

OBJECTIVE

The objective of the study was to evaluate the impact of a labor and delivery care bundle on adverse obstetrics outcomes as measured by a modified Obstetrics Adverse Outcomes Index, Weighted Adverse Outcomes Index, and Severity Index.

STUDY DESIGN

This is a retrospective cohort study including all women who delivered at our academic, tertiary care institution over a 3 year period of time, before and after the implementation of an intervention to decrease adverse outcomes. Outcome measures consisted of previously reported indices that were modified including the addition of hypoxic ischemic encephalopathy. The adverse outcomes index is a percentage of deliveries with 1 or more adverse events, the weighted adverse outcomes index is the sum of the points assigned to cases with adverse outcomes divided by the number of deliveries, and the severity index is the sum of the adverse outcome scores divided by the number of deliveries with an identified adverse outcome. A segmented regression analysis was utilized to evaluate the differences in the level and trend of each index before and after our intervention using calendar month as the unit of analysis.

RESULTS

During the study period, 5826 deliveries met inclusion criteria. Comparing the pre- and postintervention periods, high-risk pregnancy was more common in the postintervention period (73.5% vs 79.4%, P < .001). Overall, there was a decrease in both the Modified Weighted Adverse Outcomes Index (P = .0497) and the Modified Severity Index (P = 0.01) comparing the pre- and postintervention periods; there was no difference in the Modified Adverse Outcomes Index (P = .43). For low-risk pregnancies, there was no significant difference in the levels for any of the measured indices over the study period (P = .61, P = .41, and P = .34 for the Modified Adverse Outcomes Index, Modified Weighted Adverse Outcomes Index, and Modified Severity Index, respectively). Among the high-risk pregnancies, the monthly Modified Weighted Adverse Outcomes Index decreased by 4.2 ± 1.8 (P = .03). The monthly Modified Severity Index decreased by 53.9 ± 17.7 points from the pre- to the postintervention periods (P = .01) and was < 50% of the predicted Modified Severity Index had the intervention not been implemented. The cesarean delivery rate was increasing prior to the intervention, but the rate was stable after the intervention, and the absolute rate did not differ between the pre- and the postintervention periods (28.4% vs 30.0%, P = .20).

CONCLUSION

Overall and for high-risk pregnancies, the implementation of the labor and delivery care bundle had a positive impact on the Modified Weighted Adverse Outcomes Index and Modified Severity Index but not the Modified Adverse Outcomes Index.

Predicting Cesarean Delivery After Induction of Labor Among Nulliparous Women at Term

OBJECTIVE

To identify independent risk factors for cesarean delivery after induction of labor and to develop a nomogram for predicting cesarean delivery among nulliparous women undergoing induction of labor at term.

METHODS

This is a retrospective cohort study including nulliparous women with singleton, term (37 0/7 weeks of gestation or greater), cephalic pregnancies undergoing induction of labor from July 1, 2006, through May 31, 2012, at a tertiary care academic center. Inductions were identified using International Classification of Diseases, 9th Revision codes. Demographic, delivery, and outcome data were abstracted manually from the medical record. Women with a contraindication to vaginal delivery (malpresentation, abnormal placentation, prior myomectomy) were excluded. Independent risk factors for cesarean delivery were identified using logistic regression.

RESULTS

During the study period, there were 785 nulliparous inductions that met study criteria; 231 (29.4%) underwent cesarean delivery. Independent risk factors associated with an increased risk of cesarean delivery included older maternal age, shorter maternal height, greater body mass index, greater weight gain during pregnancy, older gestational age, hypertension, diabetes mellitus, and initial cervical dilation less than 3 cm. A nomogram was constructed based on the final model with a bias-corrected c-index of 0.709 (95% confidence interval 0.671-0.750).

CONCLUSION

We identified independent risk factors that can be used to predict cesarean delivery among nulliparous women undergoing induction of labor at term. If validated in other populations, the nomogram could be useful for individualized counseling of women with a combination of identifiable antepartum risk factors.

LEVEL OF EVIDENCE

II.

Safety of culdotomy as a surgical approach: implications for natural orifice transluminal endoscopic surgery

OBJECTIVE

To evaluate the efficacy and safety of culdotomy as a surgical approach to access the peritoneal cavity and discuss its implications for natural orifice transluminal endoscopic surgery (NOTES).

METHODS

A retrospective chart review of women undergoing culdotomy for tubal sterilization (N 219) between January 1995 and December 2005 was performed. The Accordion Grading System was used for the severity of complications.

RESULTS

No intraoperative complications were noted. Postoperative complications occurred in 7 patients (3.2%): 6 infections (grade 2) and 1 case of hemorrhage (grade 3). Conversion to laparoscopy was necessary in 10 patients (2.2%) due to anatomical constraints or pelvic adhesions; however, culdotomy with entry into the abdominal cavity was nevertheless successful in all 10 cases. The difference in the proportion with a history of pelvic surgery between the conversion and nonconversion groups was not statistically significant (P = .068). Patients with BMI ≥30 had a higher conversion rate compared to patients with BMI <30 (11.4% versus 1.5%, P = .011). Tubal sterilization via culdotomy was successfully performed in all 11 women with no prior vaginal deliveries.

CONCLUSION

Culdotomy appears to be a safe surgical approach to access the peritoneal cavity and is associated with a low complication rate. These data support the feasibility and safety of utilizing the cul-de-sac as an access portal for natural orifice transluminal endoscopic surgery.