J Matern Fetal Neonatal Med. 2026 Dec;39(1):2633047. doi: 10.1080/14767058.2026.2633047. Epub 2026 Feb 22.
ABSTRACT
OBJECTIVE: To investigate non-linear associations between pre-pregnancy BMI and new-onset hypertensive disorders of pregnancy (HDP), and the relationship between gestational weight gain (GWG) trajectories and HDP.
METHODS: Using data from the Ningbo Birth Cohort of Population Undergoing ART (NBart) cohort (June 2018-June 2024), we included women with singleton ART pregnancies. Restricted cubic splines, latent class mixed models, and logistic regression were applied.
RESULTS: Of 4219 eligible pregnancies, 255 (6.0%) developed HDP. Risk increased when pre-pregnancy BMI exceeded 21.5 kg/m2 (∼6% higher per 0.5 kg/m2 gain). In stratified analyses, risk also increased below 16.6 kg/m2; the J-shaped relationship was evident in normal-weight women; a significant non-linear association was not detected within the overweight and obese subgroups alone. Advanced maternal age, nulliparity, primary infertility, and frozen embryo cycle amplified BMI-related risk. Exceeding recommended GWG guidelines at various pregnancy stages increased HDP risk; refined GWG thresholds were proposed for ART pregnancies. Two GWG patterns-concave negative (0-20 ± 1 weeks; aOR = 0.540, 95% CI: 0.290-0.944) and delayed acceleration (entire gestation period; aOR = 0.627, 95% CI: 0.380-0.996)-were inversely associated with HDP. Both featured minimal or negative early-pregnancy weight change followed by steady gain, occurred predominantly in overweight and obese women, and total GWG was lower compared with other patterns.
CONCLUSIONS: Maintaining optimal pre-pregnancy BMI and adhering to the proposed, more conservative GWG thresholds for ART pregnancies may reduce HDP risk. Distinct GWG trajectories may further modulate this risk.
PMID:41724573 | DOI:10.1080/14767058.2026.2633047