Validation of claims-based algorithms to identify non-live birth outcomes.

PURPOSE: Perinatal epidemiology studies using healthcare utilization databases are often restricted to live births, largely due to the lack of established algorithms to identify non-live births. The study objective was to develop and validate claims-based algorithms for the ascertainment of non-live births. METHODS: Using the Mass General Brigham Research Patient Data Registry 2000-2014, we assembled a cohort of women enrolled in Medicaid with a non-live birth. Based on ≥1 inpatient or ≥2 outpatient diagnosis/procedure codes, we identified and randomly sampled 100 potential stillbirth, spontaneous abortion, and termination cases each. For the secondary definitions, we excluded cases with codes for other pregnancy outcomes within ±5 days of the outcome of interest and relaxed the definitions for spontaneous abortion and termination by allowing cases with one outpatient diagnosis only. Cases were adjudicated based on medical chart review. We estimated the positive predictive value (PPV) for each outcome. RESULTS: The PPV was 71.0% (95% CI, 61.1-79.6) for stillbirth; 79.0% (69.7-86.5) for spontaneous abortion, and 93.0% (86.1-97.1) for termination. When excluding cases with adjacent codes for other pregnancy outcomes and further relaxing the definition, the PPV increased to 80.6% (69.5-88.9) for stillbirth, 86.6% (80.5-91.3) for spontaneous abortion and 94.9% (91.1-97.4) for termination. The PPV for the composite outcome using the relaxed definition was 94.4% (92.3-96.1). CONCLUSIONS: Our findings suggest non-live birth outcomes can be identified in a valid manner in epidemiological studies based on healthcare utilization databases.

Variation in Cervical Length over Time during a Single Transvaginal Ultrasound Examination.

OBJECTIVE: To quantify the degree of change in cervical length (CL) over a 3-minute transvaginal ultrasound. STUDY DESIGN: We conducted a prospective observational study of nulliparous patients who underwent routine transvaginal CL screening at the time of their second-trimester ultrasound. We recorded CL at four time points (0, 1, 2, 3 minutes) and compared these values to determine the minute-to-minute change within a single patient. RESULTS: A total of 771 patients were included. The mean gestational age was 20.8 weeks (±0.84). We used a linear mixed effect model to assess if each minute during the ultrasound is associated with a change in CL. The intraclass correlation coefficient between minute 0 to minute 3 was 0.82 (95% confidence interval: 0.80, 0.84). This indicates that there is a relatively high within-patient correlation in CL during their ultrasound. Additionally, we stratified patients based on their starting CL; the intraclass correlation coefficient remained high for all groups. We additionally compared CL at each minute. Although there is a statistically significant difference between several time points, the actual difference is small and not clinically meaningful. CONCLUSION: The variation in CL over a 3-minute transvaginal ultrasound examination is not clinically significant. It may be reasonable to conduct this examination over a shorter period.

A randomized controlled trial comparing the efficacy of nifedipine and enalapril in the postpartum period.

BACKGROUND: Postpartum hypertension is a common medical complication of pregnancy and is associated with increased healthcare use, including unplanned interactions with the medical system and readmission, which can add significant stress to both a newly postpartum patient and the medical care delivery system. We currently do not know what the best antihypertensive treatment for postpartum hypertension is and tend to use antihypertensives commonly used during pregnancy. However, the mechanism of action of angiotensin-converting enzyme inhibitors may be well suited for the pathophysiology of hypertension in the postpartum period and may help to provide better control of hypertension and, in turn, decrease healthcare use. OBJECTIVE: This study aimed to determine if enalapril is superior to nifedipine in preventing prolonged hospitalizations, unplanned medical visits, and/or readmission among women with postpartum hypertension. STUDY DESIGN: We performed an open-label, randomized controlled trial (ClinicalTrials.gov registered: NCT04236258) in which patients ≥18 years with chronic hypertension, gestational hypertension, or preeclampsia were recruited to receive either 10 mg enalapril daily or 30 mg extended-release nifedipine daily as an initial antihypertensive agent in the period from delivery to 6 weeks postpartum. Recruitment occurred at a tertiary academic hospital from January 2020 to February 2021. Exclusion criteria included being on an antihypertensive when pregnancy started or requiring ≥2 daily antihypertensives during pregnancy. The antihypertensive regimen was managed by the participants' obstetrical provider after the initial randomization. The primary outcome was a composite of prolonged hospitalization, unplanned clinic visits, triage visits, and/or readmission. A total of 40 patients in each arm were needed to detect a decrease in the primary outcome rate from 70% to 40% (α=0.05; power 0.80). Analyses were performed based on the intention-to-treat principal, and each arm was oversampled because of the risk for participant dropout. RESULTS: A total of 47 patients were randomized to each arm. Aside from the mode of delivery and twin gestation, the maternal demographics were similar between the 2 groups. The primary outcome occurred in 31 of 47 patients (66%) randomized to the nifedipine group and in 30 of 47 (64%) randomized to the enalapril group (P=.83). There was no significant difference in the primary outcome after controlling for mode of delivery and twin gestation. More patients in the enalapril arm had a second antihypertensive added during their primary hospitalization (16 vs 6) and more patients in the nifedipine arm were still on their antihypertensive at 2 weeks postpartum (42 vs 36). There were no adverse events in either group. CONCLUSION: Enalapril was not superior to nifedipine when used as an initial antihypertensive in the immediate postpartum period in terms of decreasing healthcare use.

Readmission for postpartum eclampsia in the United States.

OBJECTIVE: To characterize the contemporary prevalence of eclampsia in the United States and determine whether eclampsia is taking place during the delivery hospitalization or a postpartum readmission. STUDY DESIGN: We conducted a retrospective cohort using the 2016 Nationwide Readmission Database, a discharge database of all hospitalizations in 27 states in the U.S. Through the database, we identified women with an admission for delivery of a neonate > 20 weeks gestation. We also identified readmissions that occurred within 6 weeks after discharge from that delivery admission. ICD-10-CM codes were used to identify deliveries, eclampsia and co-morbidities. The primary outcome was timing of eclampsia relative to discharge from the delivery admission. RESULTS: We identified 1,590,563 deliveries of which 2955 (0.19%) were complicated by eclampsia during the delivery admission or a postpartum readmission. Of these cases of eclampsia, 1575 (53.5%) occurred during the delivery admission, 1354 (45.8%) during a postpartum readmission and 26 (0.88%) during both the delivery and a postpartum readmission. Of the 1380 readmissions with eclampsia, 1117 (81%) occurred within the first week after delivery discharge. Another 194 (14%) occurred in the second week after discharge. Women with readmissions for eclampsia were older (30.1 vs. 28.8 years; p < .01), delivered earlier (37.7 vs. 38.5 weeks; p < .01), and more likely to have a cesarean delivery (48.4 vs. 32.4%; p < .01) or multiple gestation (4.0 vs. 1.8%; p < .01) as compared to those not readmitted for eclampsia and 44% had any hypertensive disorder during the delivery admission (vs. 12.2% without an eclampsia readmission; p < .01). CONCLUSION: Of the 2955 cases of eclampsia identified, almost half of them occurred after discharge from the delivery admission, 95% of which occurred within the first 2 weeks after discharge, demonstrating the prominence of postpartum eclampsia which may warrant new strategies for prevention and education targeted at postpartum patients after delivery hospitalization.