Efficacy of Postpartum Pharmacologic Thromboprophylaxis: A Systematic Review and Meta-analysis

OBJECTIVE

To evaluate the effectiveness of pharmacologic venous thromboembolism (VTE) prophylaxis in postpartum patients.

DATA SOURCES

On February 21, 2022, a literature search was conducted on Embase.com, Ovid-Medline All, Cochrane Library, Scopus, and ClinicalTrials.gov using terms postpartum period AND thromboprophylaxis AND antithrombin medications including heparin and low molecular weight heparin.

METHODS OF STUDY SELECTION

Studies that evaluated the outcome of VTE among postpartum patients exposed to pharmacologic VTE prophylaxis with or without a comparator group were eligible for inclusion. Studies of patients who received antepartum VTE prophylaxis, studies in which this prophylaxis could not be definitively ruled out, and studies of patients who received therapeutic dosing of anticoagulation for specific medical problems or treatment of VTE were excluded. Titles and abstracts were independently screened by two authors. Relevant full-text articles were retrieved and independently reviewed for inclusion or exclusion by two authors.

TABULATION, INTEGRATION, AND RESULTS

A total of 944 studies were screened by title and abstract, and 54 full-text studies were retrieved for further evaluation after 890 studies were excluded. Fourteen studies including 11,944 patients were analyzed: eight randomized controlled trials (8,001 patients) and six observational studies (3,943 patients). Among the eight studies with a comparator group, there was no difference in the risk of VTE between patients who were exposed to postpartum pharmacologic VTE prophylaxis and those who were unexposed (pooled relative risk 1.02, 95% CI 0.29-3.51); however, six of eight studies had no events in either the exposed or unexposed group. Among the six studies without a comparator group, the pooled proportion of postpartum VTE events was 0.00, likely due to five of six studies having no events.

CONCLUSION

The current literature provided an insufficient sample size to conclude whether postpartum VTE rates differ between those exposed to postpartum pharmacologic prophylaxis and those unexposed, given the rarity of VTE events.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO, CRD42022323841.

Simplifying the prediction of vaginal birth after cesarean delivery: role of the cervical exam

OBJECTIVE

Predicting likelihood of vaginal birth after cesarean (VBAC) is a cornerstone in counseling patients considering a trial of labor after cesarean (TOLAC). Yet, the simplified Bishop score (SBS), a score comprised cervical dilation, station, and effacement assessment used to predict successful vaginal delivery, has not been applied to the TOLAC population. We evaluated the relationship between admission SBS and likelihood of successful VBAC. We also determined the predictive characteristics of SBS, compared to cervical dilation alone, for successful VBAC.

METHODS

This is a secondary analysis of a prospective cohort study of patients with a singleton gestation, ≥37 0/7 weeks gestation, and prior cesarean admitted to Labor & Delivery between 2010 and 2014. The primary outcome of successful VBAC was compared between those with a favorable (score >5) and unfavorable (score ≤5) admission SBS. Secondary outcomes were select maternal and neonatal outcomes. Adjusted risk ratios were estimated using multivariable logistic regression analyses. Receiver-operating characteristic curves compared predictive capabilities of cervical dilation alone to SBS for successful VBAC.

RESULTS

Of the 656 patients who underwent a TOLAC during the study period, 421 (64%) had a successful VBAC. 203 (31%) and 453 (69%) had a favorable and an unfavorable admission SBS, respectively. After adjusting for body mass index and prior vaginal delivery, patients with a favorable admission SBS had a 30% greater likelihood of successful VBAC compared to those with an unfavorable SBS (aRR 1.30, 95% CI 1.16-1.40). Admission cervical dilation alone performed similarly to SBS as a predictor of successful VBAC, with a receiver-operator characteristic curve area under the curve (AUC) of 0.68 (95% CI 0.64-0.72) versus an AUC 0.66 (95% CI 0.62-0.70), respectively (p = .07). There were no differences in adverse maternal or neonatal outcomes between those with an unfavorable and favorable SBS.

CONCLUSIONS

A favorable admission SBS is associated with an increased likelihood of VBAC. Although both admission SBS and cervical dilation alone are only modest predictors of VBAC, admission cervical dilation performs overall similarly to current models for VBAC prediction and is an objective, reproducible, and generalizable measure. Our study highlights the value of waiting until end of pregnancy (rather than the first prenatal visit) to conclude patient counseling on the decision to TOLAC in order to consider admission cervical assessment, particularly cervical dilation.

Changes in the Antenatal Utilization of High-Risk Obstetric Services and Stillbirth Rate during the COVID-19 Pandemic

OBJECTIVE

The primary objective of this study was to evaluate coronavirus 2019 (COVID-19) pandemic-related changes in the antenatal utilization of high-risk obstetric services. Our secondary objective was to characterize change in stillbirth rate during the pandemic.

STUDY DESIGN

This is a retrospective, observational study performed at a single, tertiary care center. Maternal-Fetal Medicine (MFM) visits, ultrasounds, and antenatal tests of fetal well-being during the pandemic epoch (2020), which spans the first 12 weeks of the year to include pandemic onset and implementation of mitigation efforts, were compared with the same epoch of the three preceding years visually and using general linear models to account for week and year effect. An analysis of stillbirth rate comparing the pandemic time period to prepandemic was also performed.

RESULTS

While there were decreased MFM visits and antenatal tests of fetal well-being during the pandemic epoch compared with prepandemic epochs, only the decrease in MFM visits by year was statistically significant (p < 0.001). The stillbirth rate during the pandemic epoch was not significantly different when compared with the prepandemic period and accounting for both week (p = 0.286) and year (p = 0.643) effect.

CONCLUSION

The COVID-19 pandemic resulted in a significant decrease in MFM visits, whereas obstetric ultrasounds and antenatal tests of fetal well-being remained unchanged. While we observed no change in the stillbirth rate compared with the prepandemic epoch, our study design and sample size preclude us from making assumptions of association. Our findings may support future work investigating how changes in prenatal care for high-risk obstetric patients influence perinatal outcomes.

KEY POINTS

· MFM visits significantly decreased during the COVID-19 pandemic epoch.. · The overall stillbirth rate during the COVID-19 pandemic epoch was not significantly changed.. · Larger studies are needed to capitalize on these changes to evaluate rare outcomes such as stillbirth..

Offering onsite COVID-19 vaccination to high-risk obstetrical patients: initial findings

OBJECTIVE

The COVID-19 pandemic has had a disproportionate effect on pregnant women, with higher rates of viral infection and disease severity.¹ The development of highly effective vaccines has significantly reduced SARS-CoV-2 transmission and clinical disease.² However, vaccine uptake has been low in the pregnant population.³ The Centers for Disease Control and Prevention guidance suggests that limited vaccine access, not vaccine hesitancy, has driven the lower uptake rates in at-risk populations.⁴ We describe our experience with vaccination uptake rates among high-risk obstetrical patients before and after onsite BNT162b2 messenger RNA vaccination availability in outpatient clinics as part of a pilot program to improve vaccine access among pregnant patients.

STUDY DESIGN

This was a quality improvement project at a single academic medical center. Onsite vaccination was available once a week at 2 high-risk obstetrical clinics staffed by obstetrical residents, maternal-fetal medicine (MFM) fellows, and MFM attendings were selected for our vaccine pilot program. Onsite vaccinations were immediately available for use in the clinic starting May 11, 2021. Data were collected over a 4-week period (April 27, 2021, to May 20, 2021), which included 4 clinic days before onsite vaccine availability (April 27, 2021 to May 10, 2021) and 4 days with onsite vaccine availability (May 11, 2021, to May 20, 2021). Patients were considered exposed to onsite vaccination if they had any clinic visits during the latter 2 weeks of the study period. All patients were counseled by providers at each visit using our institution's standardized COVID-19 vaccination discussion tool designed for pregnant and breastfeeding patients.⁵ Counseling was documented in each patient's chart per the American College of Obstetricians and Gynecologists. Before and throughout the study period, pregnancy was listed as a qualifying condition for priority vaccination in Missouri and Illinois. At this time, vaccinations were readily available in the local area surrounding our clinical space. Data on vaccine administration were collected via the Missouri and Illinois state databases over a period of 1 month after the pilot program was closed, allowing for the collection of data on patients who pursued vaccination offsite for scheduling or personal reasons. This project was deemed exempt by the Office for Human Research Protections.

RESULTS

We reviewed data from 124 clinic visits, where a total of 93 individual patients were seen in the 4-week period; 6 had previously been vaccinated at external sites and the remaining 87 were eligible (Figure). The majority of our patient population was non-Hispanic Black women with public or no insurance (Table). Of the 32 eligible patients seen and counseled before onsite vaccination availability, 1 (3%) proceeded to receive the vaccination offsite. Of the 55 eligible patients seen and counseled after onsite vaccination availability, 2 (3%) proceeded with onsite vaccination and an additional 4 (7%) proceeded with vaccination offsite. Onsite vaccination availability did not significantly increase the vaccination rates (3% vs 11%; P=.22). Of the 55 eligible patients counseled during onsite vaccination availability, 25 were seen and counseled exclusively during the onsite vaccination pilot period and none of these patients accepted onsite vaccination or pursued vaccination offsite.

CONCLUSION

Because only 3% of eligible, high-risk obstetrical patients proceeded with onsite vaccination, our experience suggests that vaccine hesitancy, not availability, is a critical driver of the low vaccination rates in this population. Although a larger sample size may have demonstrated statistical difference, the overall low vaccination uptake rate forced the closure of our pilot program over concerns for wasted vaccination doses. In a population at high risk for progression to severe COVID-19, only 14% of our study population was vaccinated, whereas Missouri reported a 41% vaccination rate during this time.⁶ These findings suggest that increased access alone may not improve vaccination rates in obstetrical patients even after counseling by expert clinicians. These findings are limited by the pre/post nature of the comparison, exposing the sample to bias as vaccination recommendations and population sentiment was rapidly evolving during this time period. However, the consistency of counseling and patient population provided by a single clinical setting limited other sources of bias during the study period. Vaccine hesitancy is multifactorial and complex and urgently requires more evaluation in this high-risk population. Vaccine hesitancy in pregnancy is well documented, but early reports suggest that the COVID-19 vaccination uptake rate is markedly lower than that of other vaccines during pregnancy. Our finding that none of the women who were seen exclusively during the onsite vaccination period accepted vaccination may suggest that repeat clinic visits and the associated establishment of rapport and trust is a vital part of vaccine decision making. Earlier intervention, before patient views on novel therapeutics such as vaccinations can be formulated and fixed, may aid in uptake. Further qualitative work and inclusion of pregnant women in vaccine trials is an initial step.

Performance of middle cerebral artery doppler for prediction of recurrent fetal anemia

OBJECTIVE

To assess the predictive value of middle cerebral artery Doppler peak systolic velocity (MCA-PSV) for moderate-severe fetal anemia following one intrauterine transfusion (IUT) and test the performance of alternate cutoffs to the recommended threshold ≥1.69 multiples of the median (MoM).

METHODS

This was a retrospective cohort study of patients with pregnancies affected by alloimmunization who underwent percutaneous umbilical blood sampling (PUBS) procedures from 2000 to 2020. An MCA-PSV ≥1.69 MoM was the indication for the second IUT. The primary outcome was recurrent moderate-severe fetal anemia. Receiver-operating characteristic (ROC) curves assessed the predictive ability of MCA-PSV for the primary outcome and the Youden index identified the "optimal" cutoff value. Predictive characteristics of MCA-PSV ≥1.69 MoM and the "optimal" cutoff were compared.

RESULTS

Of the 58 patients who underwent IUT during the study period, 36 (62%) did not meet inclusion criteria. Of the remaining 22 patients who underwent a second PUBS, 12 (54.6%) fetuses had moderate or severe anemia. Following one IUT, the AUC for MCA-PSV was 0.86 (95% CI 0.70-1.00) for the primary outcome. The "optimal" cutoff MCA-PSV value was 1.74 MoM, which had a greater specificity than ≥1.69 MoM (90 vs. 50%, p = .05), but was not statistically significant. The sensitivity was similar between the two cutoff values of ≥1.69 and ≥1.74 MoM (83.3 vs. 75.0%, p = .65) (Table 2).

CONCLUSION

Raising the recommended MCA-PSV cutoff to ≥1.74 MoM for recurrent moderate-severe fetal anemia after one IUT would decrease the number of unnecessary procedures without significantly changing the sensitivity of this screening test.

Complicated placenta accreta spectrum: identifying a high-risk cohort

OBJECTIVE

To assess differences in the perioperative complication rate between patients with placenta accreta spectrum (PAS) with and without complicating factors.

METHODS

This retrospective cohort study included subjects who underwent cesarean hysterectomy with histology-proven PAS between 23 0/7 and 42 0/7 weeks gestational age (GA) from 1 July 2008 to 11 April 2017. Perioperative outcomes were compared between those with uncomplicated PAS and "complicated PAS," defined as PAS subjects who experienced ≥2 bleeding episodes, preterm premature rupture of membranes (PPROM), or premature contractions requiring tocolysis.

RESULTS

Overall, 26 complicated PAS and 27 uncomplicated PAS cases were compared; no difference in the rate of perioperative complications was identified. An increased proportion of complicated PAS cases required blood product transfusion before delivery: 2 (40%), 3 (27.3%), and 2 patients (20%) for those with PPROM, preterm contractions, and ≥2 bleeding episodes respectively, compared to patients with uncomplicated PAS, having no transfusions (p = .001). Time of delivery was earlier for patients with complicated compared to uncomplicated PAS (median GA 30.9 [Q1 = 27.9; Q3 = 31.9] and 34.9 [Q1 = 32.1; Q3 = 35.7], p < .001). Median birthweights were lower (p < .0144) and maternal length of stay longer (p < .0012) for complicated PAS.

CONCLUSION

Patients with complicated PAS were not at higher risk for perioperative complications but were associated with earlier delivery, required more antenatal blood transfusions, and had a longer LOS.

Pregnancy as a risk factor for severe coronavirus disease 2019 using standardized clinical criteria

BACKGROUND

As of November 18, 2020, more than 11 million people have been infected with coronavirus disease 2019 and almost 250,000 people have died from the disease in the United States, less than 1 year since its discovery. Although literature is beginning to emerge on pregnancy as a risk factor for severe coronavirus disease 2019, these studies are heterogeneous and use primary outcomes such as intensive care unit admission or hospitalization as surrogate markers that may subject analyses to misclassification bias in pregnant patients.

OBJECTIVE

This study aimed to determine the risk of severe coronavirus disease 2019 among pregnant women with symptomatic coronavirus disease 2019 compared with nonpregnant women using nonadmission-based, standardized clinical criteria for severe disease.

STUDY DESIGN

This is a retrospective cohort study of women aged 13 to 45 years and diagnosed as having symptomatic coronavirus disease 2019 between May 28, 2020, and July 22, 2020. The primary outcome was severe coronavirus disease 2019 as defined by 2 sets of nonadmission-based, clinical criteria: the World Health Organization Ordinal Scale for Clinical Improvement and the Novel Coronavirus Pneumonia Emergency Response Epidemiology Team. Adjusted risk ratios were estimated using multivariable logistic regression analyses.

RESULTS

Of 262 women aged 13 to 45 years with symptomatic coronavirus disease 2019, 22 (8.4%) were pregnant and 240 (91.6%) were nonpregnant. After adjusting for covariates potentially associated with the primary outcome, symptomatic pregnant women were at a significantly increased risk of severe coronavirus disease 2019 compared with nonpregnant women using both the World Health Organization Ordinal Scale for Clinical Improvement (adjusted relative risk, 3.59; 95% confidence interval, 1.49–7.01) and Novel Coronavirus Pneumonia Emergency Response Epidemiology Team (adjusted relative risk, 5.65; 95% confidence interval, 1.36–17.31) criteria.

CONCLUSION

Pregnancy significantly increases the risk of severe coronavirus disease 2019 as defined by nonadmission-based, clinical criteria.

Ibuprofen and Postpartum Blood Pressure in Women With Hypertensive Disorders of Pregnancy: A Randomized Controlled Trial

OBJECTIVE

To evaluate the effect of ibuprofen on blood pressure in women with a diagnosis of hypertensive disorders of pregnancy and mild hypertension during the immediate postpartum period.

METHODS

In this double-blind controlled trial, we randomly assigned women with a diagnosis of hypertensive disorders of pregnancy and mild hypertension to receive a postpartum analgesic regimen with either ibuprofen or acetaminophen. The primary outcome was average mean arterial pressure during the postpartum hospital stay. Prespecified secondary outcomes included use of breakthrough opioid pain medications, length of hospital stay, and postpartum diuresis, defined as urine output of at least 200 mL/hour for 4 hours. A sample size of 56 participants was needed to detect a difference of 6 mm Hg in average mean arterial pressure between the study groups.

RESULTS

From January 17, 2017, to February 24, 2018, 61 participants were randomized and completed the trial, 31 participants in the ibuprofen group and 30 in the control group. Baseline characteristics were similar between groups. Postpartum average arterial pressure did not differ between study groups (93±8 mm Hg for those in the ibuprofen group vs 93±7 mm Hg in the control group, P=.93). Breakthrough opioid medications were requested by 24% of the participants in the ibuprofen group compared with 30% in the control group (P=.62). The ibuprofen group did not have a longer length of stay (48 hours vs 43 hours in the control group) or decreased rate of postpartum diuresis (61% in ibuprofen group vs 77% in the control group, P=.2).

CONCLUSION

In women with hypertensive disorders of pregnancy and mild hypertension, ibuprofen did not increase postpartum blood pressure compared with women not receiving nonsteroidal antiinflammatory drugs.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov NCT03011567.

Advances in prenatal and perinatal diagnosis and management of gastroschisis

Gastroschisis is a congenital, ventral wall defect associated with bowel evisceration. The defect is usually to the right of the umbilical cord insertion and requires postnatal surgical correction. The fetus is at risk for complications such as intrauterine growth restriction, preterm delivery, and intrauterine fetal demise. In addition, complex cases, defined by the presence of intestinal complications such as bowel atresia, stenosis, perforation, or ischemia, occur in up to one third of pregnancies affected by gastroschisis. As complex gastroschisis is associated with increased morbidity and mortality, research has focused on the prenatal detection of this high risk subset of cases. The purpose of this review is to discuss the prenatal, diagnostic approach to the identification of gastroschisis, to describe potential signs of complex gastroschisis on prenatal ultrasound, to review current guidelines for antepartum management and delivery planning, and to summarize results of both past and current intervention trials in fetuses with gastroschisis.