A multicountry study to establish rates for pregnancy and neonatal outcomes in low- and middle-income regions.

Authors

Antonella Nadia Tullio, Emad Yanni, Conrado Milani Coutinho, Lavitha Sivapatham, Christine Mui Fong Lee, Sridevi Pallem, Yongjia Pu, Agnes Akawung, Joon Hyung Kim, Ouzama Henry, Marisa Marcia Mussi-Pinhata, Khatija Ahmed, Clara Del Carmen Flores Acosta, Osvaldo Reyes, Ivonne Abadía de Regalado, Diana Andrea Arias Fernandez, Linda Aurpibul, Sri Wahyu Taher, Juliana Caccavo, Ana Ceballos, Chenchit Pichailuck, Ulises D'Andrea Nores, Tirza De Leon, Mara De Bernardi, Pablo Dieser, Emily Christine D'Silva, Andrea Falaschi, Samantha Fry, Angela Gentile, Ik Hui Teo, Sheena Kotze, Eduardo Lopez-Medina, Ruben Luca, Maria Florencia Lucion, Jacinto Blass Iii V Mantaring, Bladimir Marin, Malahleha Moelo, Jorge Pinto, Thanyawee Puthanakit, Maria Fernanda Roa, Maria Teresa Rodriguez Brieschke, Camilo Enrique Rodriguez, Juan Nicolas Rodriguez Niño, Alexandre Vargas Schwarzbold, Alexandra Sierra Garcia, Ruey Soon, Juan Carlos Tinoco, Jesús Arnulfo Velásquez Penagos, Khalequ Zaman, Gaël Dos Santos

Published in

BMC pregnancy and childbirth. Volume 26. Issue 1. Jan 14, 2026. Epub Jan 14, 2026.

Abstract

Maternal vaccines can reduce the burden of diseases for both mother and neonate. The development and implementation of such vaccines require a thorough interpretation of safety data and standardized disease case definitions. This study aimed to evaluate the current rates for adverse pregnancy outcomes, maternal and neonatal events of interest (EOIs) that will be informative for preparing future phase III clinical trials on maternal vaccines conducted in low- and middle-income countries and further assisting in safety data interpretation (e.g., monitoring potential safety signals in clinical trials, and/or helping with the causality assessments of adverse events following immunization).
We performed a prospective cohort study on healthy 18-45-year-old women, with singleton, low-risk pregnancies, with a gestational age of ≥24^0/7 weeks at enrollment and ≤27^6/7 weeks at first visit, and their neonates. The study was conducted between 2019-2021 in 10 countries that were considered low- and middle-income countries by the World Bank Group at the time the study was designed. All pregnancy-related outcomes and maternal EOIs occurring from enrollment up to 42 days post-delivery and neonatal EOIs occurring within the first 28 days after birth were recorded.
Of 2311 pregnant women and 2181 neonates enrolled, 2222 and 2094 were included in the analyses, respectively. Most livebirths (2088 [94.0%]) were without apparent congenital anomalies. Preterm delivery (166 [7.5%]), non-reassuring fetal status (137 [6.2%]), and hypertensive disorders of pregnancy (125 [5.6%]) were the most frequently reported EOIs related to pregnancy. The most frequent neonatal EOIs were low birthweight (including very low birthweight) (156 [7.4%]), preterm birth (141 [6.7%]), small for gestational age (111 [5.3%]), and congenital anomalies (103 [4.9%], including mainly major external structural defects, as well as detected internal and functional defects). Overall, there were similar frequencies in pregnancy outcomes, pregnancy-related and neonatal EOIs across countries, although some variation in the reporting rate was noted.
This multicountry study contributes to establishing the most recent background rates for pregnancy outcomes, maternal and neonatal EOIs in low- and middle-income regions. The clinical relevance in the context of the safety assessment in future trials will be applied.
NCT03614676 (03/08/2018).

PMID:
41535781
Bibliographic data and abstract were imported from PubMed on 23 Jul 2026.

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