Differential associations of mid-pregnancy blood pressure components and glucose with late-pregnancy fetal growth trajectories
H Shi, J Yang, Y Fang, L Zuo, R Zhang, G Aa, Q Yang, X ZhouAbstract
Background
According to the Developmental Origins of Health and Disease (DOHaD) theory, the intrauterine environment determines an individual's long-term health. However, traditional static birth weight classifications ignore the dynamic continuity of fetal development and fail to elucidate the impact of the complex interaction between maternal systolic blood pressure (SBP), diastolic blood pressure (DBP), and fasting plasma glucose (FPG) on growth trajectories.
Purpose
This study aimed to identify latent fetal growth trajectories in the third trimester and evaluate the predictive value of maternal blood pressure (BP) and FPG measured during mid-pregnancy. The objective performs a comprehensive association analysis to determine how specific combinations of maternal BP and FPG predispose fetuses to disparate developmental pathways.
Methods
This retrospective cohort study included 18,364 singleton pregnancies. Maternal SBP, DBP, and FPG were measured at 20–28 weeks. Estimated fetal weight (EFW) from 29 to 41 weeks was calculated using the Hadlock formula. Group-Based Trajectory Modelling (GBTM) identified EFW trajectories. The absolute EFW model was selected for predicting growth abnormalities based on its superior Area Under the Curve (AUC) performance. The study utilised multinomial logistic regression to estimate relative risk ratios (RRR) for trajectory membership, constructed risk heatmaps to visualise the joint association of BP components and FPG, and applied quantile regression to examine how maternal glucose levels modify the maternal BP.
Results
The study identified three distinct EFW trajectories: Trajectory 1 (low-stable, 27.9%), Trajectory 2 (average-stable, 50.1%), and Trajectory 3 (high-stable/accelerated, 22.0%). Mid-pregnancy DBP was a robust independent predictor for the low-growth trajectory (Full Adjustment RRR: 1.088; 95% CI: 1.053–1.124). Conversely, after adjusting for DBP, SBP showed an inverse association with Trajectory 1 (RRR: 0.932; 95% CI: 0.890–0.976). Heatmap analysis revealed that the highest probability of falling into the low-growth trajectory (38.4%) occurred in mothers with high DBP (>80 mmHg) and low FPG (<70 mg/dL). Quantile regression showed that as maternal FPG rose, the positive coefficients of both SBP and DBP increased progressively. This suggests that maternal hyperglycaemia enhances the haemodynamic drive for fetal overgrowth.
Conclusions
Maternal DBP and SBP exert contrasting influences on fetal growth, with DBP serving as a primary predictor of growth restriction. Association analysis confirms that the interaction between maternal blood pressure and glucose levels determines fetal growth pathways. Integrated screening of maternal blood pressure and FPG in mid-pregnancy is essential for the early identification of fetuses at risk of atypical development.abstract graph