Gestational diabetes risk associated with early pregnancy blood pressure characteristics and trajectories: A Chinese prospective cohort study

BACKGROUND: Limited evidence exists regarding early pregnancy pulse pressure (PP) and blood pressure (BP) trajectories in gestational diabetes mellitus (GDM) development. Understanding these associations may provide valuable insights for early interventions to mitigate the risk of GDM. METHODS: Included were 16 020 pregnant women from the Shenzhen Maternity and Child Healthcare Hospital. Early pregnancy BP characteristics were determined based on BP measurements recorded at the initial prenatal visit, including systolic blood pressure (SBP), diastolic blood pressure (DBP), and PP. Early pregnancy SBP trajectories up to 20 weeks' gestation were identified using latent class growth mixture models (LCGM) based on multiple prenatal visits. Multivariate logistic regression analyses were performed to assess the association between early pregnancy BP characteristics and SBP trajectories with the risk of GDM. RESULTS: Among participants, 23.91% (3830/16 020) developed GDM. Moderate BP (SBP 120-139 mmHg and/or DBP 80-89 mmHg) was associated with elevated GDM risk (OR = 1.24, 95% CI 1.14-1.35), with isolated moderate SBP (120-139 mmHg) demonstrating a stronger association (OR = 1.27, 95% CI 1.16-1.38), while early pregnancy hypertension conferred an additional 32% risk elevation (OR = 1.32, 95% CI 1.02-1.71). Linear associations were observed for SBP (each 10 mmHg increase: OR = 1.14, 95% CI 1.10-1.18), DBP (each 5 mmHg: OR = 1.07, 1.05-1.09), and PP (each 5 mmHg: OR = 1.04, 1.02-1.07) with GDM risk. The highest PP tertile demonstrated a 20% elevated risk versus the lowest (OR = 1.20, 1.09-1.32). Trajectory analysis revealed four distinct SBP patterns, with escalating risks: medium-stable (OR = 1.31), medium-high stable (OR = 1.61), and peak pattern (OR = 1.98) compared with low-stable reference (all p < 0.01). CONCLUSIONS: Poor early pregnancy BP characteristics and unfavourable BP trajectories are associated with an elevated risk of GDM. These findings suggest that monitoring BP throughout early pregnancy could serve as an essential strategy for identifying women at higher risk for GDM, potentially enabling timely preventative measures.