Association of maternal height with pregnancy complications: Analyses of two cohorts

Height is inversely associated with risk of cardiovascular and metabolic conditions in nonpregnant populations. Whether maternal height is independently associated with pregnancy complications, after accounting for prepregnancy weight, remains less clear.

To investigate associations of maternal height with pregnancy complications, independent of prepregnancy weight, and to examine the role of infant sex and race/ethnicity in these associations.

We conducted a secondary analysis of data from the Omega and Hyperglycemia and Adverse Pregnancy Outcome (HAPO) prospective cohort studies of pregnant women (total N = 8763). Cohort-specific short (<20th percentile), average (20th-80th percentile), and tall (≥80th percentile) height categories were defined. Gestational diabetes mellitus (GDM), preterm birth (PTB; Omega only), and preeclampsia were considered outcomes. We fit cohort-specific unadjusted and adjusted modified Poisson regression models with robust standard errors and estimated relative risks (RRs) and 95% confidence intervals (CIs) associated with each 5-cm greater maternal height. We fit similar models to examine risks among women with short or tall height compared with average height. We evaluated race/ethnicity and infant sex as potential modifiers of height-GDM associations using interaction models.

Each 5-cm greater maternal height was associated with lower GDM risk in both cohorts, with a modest association in Omega and a larger association in HAPO (Omega: adjusted RR [aRR], 0.99; 95% CI, 0.98, 0.99; HAPO: aRR, 0.84; 95% CI, 0.78, 0.90). Short women had higher GDM risk (Omega: aRR, 1.05; 95% CI, 1.03, 1.07; HAPO: aRR, 1.44; 95% CI, 1.18, 1.75), and tall women had lower GDM risk (Omega: aRR, 0.98; 95% CI, 0.96, 0.99; HAPO: aRR, 0.71; 95% CI, 0.56, 0.89), compared with women with average height. In Omega, linear height was associated with slightly lower preeclampsia risk (aRR, 0.99; 95% CI, 0.99, 0.99) and slightly greater PTB risk (aRR, 1.01; 95% CI, 1.00, 1.01). Infant sex or race/ethnicity did not meaningfully modify the association between height and GDM in either cohort.

Maternal height was inversely associated with GDM risk in both cohorts. We also observed small, cohort-specific associations of height with PTB and preeclampsia in Omega. These findings suggest that maternal height may provide modest information beyond conventional maternal body-size measures, although its clinical utility for individual risk prediction or targeted monitoring may be limited and requires further evaluation.