Distinct risk patterns of mid-trimester systolic-diastolic blood pressure for individual and co-occurring adverse pregnancy outcomes

Background The combined contributions of maternal systolic (SBP) and diastolic blood pressure (DBP) to adverse pregnancy outcomes (APOs) remain unclear. We investigated how mid-trimester SBP-DBP levels, jointly analyzed, influence both individual APOs and co-occurring APO clusters. Methods Two cohorts from northern and southern China involving 78,891 singleton pregnancies were analyzed. Using two-dimensional SBP and DBP "heat maps", we evaluated the associations of mid-trimester (20 to 28 weeks) SBP and DBP with six major APOs (gestational diabetes [GDM], preterm birth, small-for-gestational-age [SGA], postpartum hemorrhage, placental abruption, and severe preeclampsia) both individually and as co-occurring clusters identified by latent class analysis (LCA). Results Five distinct SBP-DBP patterns emerged for individual APO risk: (1) isolated systolic (SBP+, linked to GDM), (2) isolated diastolic (DBP+, preterm birth), (3) concurrent systolic–diastolic (SBP+/DBP+, severe preeclampsia), and two divergent patterns (SBP–/DBP+ for SGA and postpartum hemorrhage; SBP+/DBP– for placental abruption). For LCA-identified four-APO classes, the "GDM-dominant" and the "SGA-dominant" classes were driven by isolated systolic and isolated diastolic patterns, respectively. The "preterm birth-dominant" class was influenced by concurrent systolic–diastolic pattern. Notably, the "placental dysfunction" class (featured by high rates of postpartum hemorrhage, placental abruption, and severe preeclampsia) was featured by isolated diastolic pattern. Pulse pressure analyses further supported these findings. Conclusions Mid-trimester SBP and DBP combine in unique ways to shape both individual and co-occurring APOs. Recognizing these SBP-DBP patterns may refine risk stratification and guide more tailored blood pressure management to improve maternal-fetal outcomes.