Work

Maternal risk stratification and planned birth improve pregnancy outcomes at term: a population-based cohort study

Year: 2025

Type: article

Abstract: Background In many countries antenatal maternal risk stratification and individualization of subsequent pregnancy care is ubiquitous. However, because of the dynamic nature of pregnancy and emergence of new risk factors as gestation progresses it is unclear whether this approach results in better pregnancy outcomes. Objective The aim of this study was to investigate the relationship between antenatal maternal risk stratification and maternal and perinatal outcomes and to ascertain if planned birth at 39 weeks resulted in better pregnancy outcomes at term. Study Design This was a retrospective cohort study of 1,167,372 singleton births over 37 +0 weeks' gestation from 2000–2021 in Queensland, Australia. Women were stratified into three risk categories (high, intermediate or low) in accordance with recommendations from international guidelines. The study outcomes were: Severe adverse maternal outcome, perinatal mortality (antepartum stillbirth, intrapartum stillbirth and neonatal death), severe neonatal neurological morbidity and maternal-infant separation. Multivariable logistic regression models were built to determine odds ratios (OR) for the effect of maternal risk strata on study outcomes and the effect of planned birth (either induction of labor or scheduled cesarean section) at 39 +0 - 39 +6 weeks compared to expectant management. Results 468,710 (40·2%) women were categorized as low-risk, 324,650 (27·8%) as intermediate-risk, and 374,012 (32·0%) as high-risk. Compared to low-risk women, the odds of severe maternal adverse outcome, perinatal mortality severe neonatal neurological morbidity and maternal-infant separation were increased in the intermediate and high-risk groups with the highest odds in the high risk cohort. The probability for severe adverse maternal outcome was lowest at 39 +0 – 39 +6 weeks for all risk categories. Regardless of maternal risk strata, the probability of perinatal mortality, was lowest at 39 +0 – 40 +6 weeks, for severe neonatal neurological morbidity it was lowest at 38 +0 – 39 +6 and for maternal-infant separation the nadir was at 39 +0 – 40 +6 weeks. For all study outcomes, the probability of an adverse outcome increased from 40 +0 weeks onwards regardless of risk category. Conclusions The risks of severe maternal and perinatal outcomes including maternal-infant separation are directly associated with antenatally determined maternal risk strata. Women in the high-risk category had the highest odds of all adverse outcomes. However, compared to expectant management, planned birth at 38 +0 - 39 +6 weeks, especially by scheduled cesarean was associated with the lowest odds of adverse outcomes particularly for women in the high-risk category.

Source: American Journal of Obstetrics and Gynecology

DOI: 10.1016/j.ajog.2025.10.005