Risk factors and perinatal outcomes for persistent placenta previa in nulliparas

Rebecca J Post; Jenny Chang; Argyrios Ziogas; Brian A Crosland; Robert M Silver; David M Haas; William A Grobman; George R Saade; Uma M Reddy; Hyagriv Simhan; Judith H Chung

doi:10.1016/j.ajogmf.2023.101136

Risk factors and perinatal outcomes for persistent placenta previa in nulliparas

Am J Obstet Gynecol MFM. 2023 Oct;5(10):101136. doi: 10.1016/j.ajogmf.2023.101136. Epub 2023 Aug 18.

Authors

Affiliations

¹ Department of Obstetrics and Gynecology, University of California, Irvine, Irvine, CA (Drs Post, Crosland, and Chung). Electronic address: rpost@uci.edu.
² Department of Medicine, University of California, Irvine, Irvine, CA (Ms Chang and Dr Ziogas).
³ Department of Obstetrics and Gynecology, University of Utah School of Medicine, Salt Lake City, UT (Dr Silver).
⁴ Department of Obstetrics and Gynecology, University of California, Irvine, Irvine, CA (Drs Post, Crosland, and Chung).
⁵ Department of Obstetrics and Gynecology, Indiana University Health, Indianapolis, IN (Dr Haas).
⁶ Department of Obstetrics & Gynecology, Northwestern University Feinberg School of Medicine, Chicago, IL (Dr Grobman).
⁷ Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, TX (Dr Saade).
⁸ Department of Obstetrics and Gynecology, Columbia University, New York City, NY (Dr Reddy).
⁹ Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Pittsburgh, Pittsburgh, PA (Dr Simhan).

PMID: 37598887
DOI: 10.1016/j.ajogmf.2023.101136

Abstract

Background: Placenta previa diagnosed on midtrimester ultrasound often resolves by the third trimester. Multiparity and previous cesarean delivery have been associated with persistence of placenta previa at delivery. Risk factors for persistent placenta previa in nulliparas are not well characterized.

Objective: This study aimed to identify risk factors for persistent placenta previa in the nulliparous population, and evaluate differences in outcomes between persistent and resolved placenta previa.

Study design: This was a secondary analysis of the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-be (nuMoM2b), a prospective cohort study that observed 10,037 nulliparous individuals throughout pregnancy. Nulliparas diagnosed with placenta previa on midtrimester ultrasound were included in this analysis. Baseline characteristics and delivery outcomes of nulliparas with persistent placenta previa were compared with those of nulliparas with resolved placenta previa. Multivariate logistic regression with stepwise model selection was used for adjusted analyses.

Results: A total of 171 nulliparas (1.7%) in the nuMoM2b study were diagnosed with placenta previa on midtrimester ultrasound, of whom 17% (n=29) had persistent placenta previa at delivery. When compared with those with resolved placenta previa, nulliparas with persistent placenta previa were more likely to be older (median, 32 years [interquartile range, 30-37] vs 29 years [interquartile range, 25-31]; P<.01), have a previous pregnancy of <20 weeks (48.3% vs 22.5%; P=.01), have a previous dilation and curettage/evacuation procedure (27.6% vs 10.6%; P=.03), or have a pregnancy that resulted from assisted reproductive technology (31% vs 4.9%; P=.01). After adjusting for potential confounders, maternal age (adjusted odds ratio, 1.11; 95% confidence interval, 1.02-1.21), in vitro fertilization (adjusted odds ratio, 9.00; 95% confidence interval, 1.97-41.14), and previous pregnancy of <20 weeks (adjusted odds ratio, 2.77; 95% confidence interval, 1.10-6.95) remained statistically significant risk factors for persistent placenta previa. Persistent placenta previa was also associated with higher likelihood of antepartum admission (10.3% vs 0%; P<.01), preterm delivery (34.5% vs 12%; P<.01), lower neonatal birthweight (median, 2847 g [interquartile range, 2655-3310] vs 3263 g [interquartile range, 2855-3560]), and cesarean delivery (100% vs 20.4%; P<.001), but there were no differences in overall pregnancy or neonatal outcomes.

Conclusion: In nulliparous individuals diagnosed with placenta previa on midtrimester ultrasound, older maternal age, previous pregnancy of <20 weeks, and in vitro fertilization are associated with persistent placenta previa at delivery.

Keywords: advanced maternal age; assisted reproductive technology; in vitro fertilization; midtrimester ultrasound; nulliparity; persistent placenta previa; placenta location; placenta previa.