Beyond BMI in Pregnancy: Can New Obesity Staging Improve Maternal Care?

Dr Bharti Kalra, Consultant, Dept. of Obstetrics and Gynecology, Bharti Hospital, Karnal, India

Obesity in pregnancy raises complication risks, and while BMI remains standard, newer staging tools like EOSS may better reflect health complexity but are not yet proven superior.

Obesity during pregnancy is strongly linked with a higher risk of maternal and neonatal complications, including gestational diabetes, preeclampsia, depression, preterm birth, shoulder dystocia, and birth-related trauma such as vaginal tears. These risks rise progressively with increasing body mass index (BMI ≥30 kg/m²), with higher BMI levels associated with worse outcomes. As a result, current clinical guidelines often recommend weight optimization before conception and closer monitoring during pregnancy, including early screening for gestational diabetes and enhanced fetal surveillance.

However, BMI alone has important limitations. It reflects only height and weight, without capturing fat distribution, metabolic dysfunction, psychological health, or functional impairment. Obesity is now understood as a chronic disease involving complex biological and psychosocial factors, making BMI an incomplete diagnostic and staging tool in clinical care, including pregnancy.

Newer frameworks such as the Edmonton Obesity Staging System (EOSS) attempt to address this gap by classifying obesity based on metabolic, physical, and mental health impacts alongside BMI. Early evidence suggests higher EOSS stages are associated with complications like cesarean delivery and hypertensive disorders, though findings remain inconsistent and limited.

Current research indicates that both BMI and EOSS correlate with adverse pregnancy outcomes, but neither has proven superior. Importantly, no studies have yet demonstrated whether EOSS improves patient-centered prenatal care.

Further research is needed before replacing or supplementing BMI in routine obstetric practice.

(Reference: Nagpal TS, Cox JM, Salas XR, Adamo KB. Measuring and Managing Obesity in Pregnancy Using the Edmonton Obesity Staging System: A Scoping Review. Clinical Obesity. 2026 Feb;16(1):e70043.)