Impact of hypertensive disorders on disease progression in pregnancies affected by early-onset fetal growth restriction.

Introduction: Fetal growth restriction is a leading cause of perinatal morbidity, often linked to placental insufficiency. Hypertensive disorders frequently coexist with fetal growth restriction and may alter its clinical course. The objective of this study is to examine how hypertensive disorders influence the onset, progression, and timing of birth in pregnancies affected by fetal growth restriction. Secondary outcomes were indications for delivery and neonatal outcomes.

Material and methods: A retrospective cohort study of pregnancies diagnosed with fetal growth restriction prior to 36 weeks' gestation and monitored under the TRUFFLE protocol between January 2013 and July 2024 at a tertiary fetal medicine unit in the UK. Pregnancies were stratified by maternal blood pressure status: normotensive, hypertensive disorder of pregnancy, or preexisting chronic hypertension. Clinical characteristics, antenatal surveillance findings, delivery indications, and neonatal outcomes were compared between groups.

Results: One hundred and ninety-six singleton pregnancies met the inclusion criteria. 68% of the cohort were affected by chronic hypertension or new-onset hypertensive disorders of pregnancy. Hypertensive pregnancies had significantly shorter intervals from fetal growth restriction diagnosis to delivery (9 days (IQR 5-19) for chronic hypertension, 12 days (IQR 3-24) for hypertensive disorders of pregnancy, 23 days (IQR 8-35) in normotensive pregnancies (p = 0.001)) and earlier gestational age at delivery (29 + 5 weeks (IQR 27 + 3-32 + 3) for chronic hypertension and 30 + 5 weeks (IQR 28 + 4-32 + 6) for hypertensive disorders of pregnancy - versus 32 + 0 weeks (IQR 29 + 1-33 + 6) in normotensive cases; p = 0.023). A higher proportion of hypertensive pregnancies were delivered for maternal indications (37.5% hypertensive disorders of pregnancy, 39.5% chronic hypertension) compared to 14.5% in normotensive pregnancies (p = 0.004), while normotensive pregnancies were more frequently delivered due to abnormal umbilical artery Dopplers (29.0% vs. 14.6% hypertensive disorders of pregnancy, 13.2% chronic hypertension; p = 0.041). Neonates of mothers with chronic hypertension had higher birthweight centiles (p = 0.004), but neonatal outcomes were comparable across all groups.

Conclusions: Incidence of hypertension in the context of fetal growth restriction significantly impacts timing and gestational age of delivery and birthweight centile. An integrated approach to combine maternal and fetal monitoring in these pregnancies is required to optimize birth outcomes.