First‐trimester maternal haemodynamic adaptation to pregnancy and placental, embryonic and fetal development: the prospective observational Rotterdam Periconception cohort

OBJECTIVE: To investigate whether first‐trimester maternal haemodynamic adaptation impacts placental, embryonic and fetal development as well as birth outcomes in pregnancies with and without placenta‐related complications. DESIGN: Prospective observational cohort. SETTING: A Dutch tertiary hospital. POPULATION: Two hundred and fourteen ongoing pregnancies. METHODS: At 7, 9 and 11 weeks of gestation, we assessed maternal haemodynamic adaptation (mean arterial blood pressure [MAP], uterine artery [UtA] blood flow) and placental development (placental volume [PV], uteroplacental vascular volume [uPVV]) using three‐dimensional power Doppler ultrasound volumes, and embryonic development (crown–rump length, embryonic volume). At 22 and 32 weeks of gestation, fetal development was assessed by estimated fetal weight. Birth outcomes (birthweight, placental weight) were extracted from medical records. Linear mixed modelling and linear regression analyses were applied. MAIN OUTCOME MEASURES: Birthweight centile and placental weight. RESULTS: In placenta‐related complications (n= 55, 25.7%), reduced haemodynamic adaptation, i.e. higher UtA pulsatility index (PI) and resistance index (RI) trajectories, was associated with smaller increase in PV (β = −0.559, 95% CI −0.841 to −0.278, P< 0.001; β = −0.579, 95% CI −0.878 to −0.280, P< 0.001) and uPVV trajectories (UtA PI: β = −0.301, 95% CI −0.578 to −0.023, P= 0.034). At birth, reduced haemodynamic adaptation was associated with lower placental weight (UtA PI: β = −0.502, 95% CI −0.922 to −0.082, P= 0.022; UtA RI: β = −0.435, 95% CI −0.839 to −0.032, P= 0.036). In pregnancies without placenta‐related complications, higher MAP trajectories were positively associated with birthweight centile (β = 0.398, 95% CI 0.049–0.748, P= 0.025). CONCLUSIONS: Reduced first‐trimester maternal haemodynamic adaptation impacts both placental size and vascularisation and birthweight centile, in particular in pregnancies with placenta‐related complications. TWEETABLE ABSTRACT: Reduced first‐trimester maternal haemodynamic adaptation to pregnancy impairs early placental development.