This article is more than 5 years old. Information may no longer be current.

Pre-pregnancy BMI linked to maternal morbidity, mortality

Pregnant women in Washington State with low and high pre-pregnancy BMI had a small but statistically significant increase in severe maternal mortality or morbidity compared to women with normal BMI, according to findings recently published in JAMA.

“Although high BMI is associated with adverse birth outcomes, the association with severe maternal morbidity is unclear,” Sarka Lisonkova, MD, PhD, of the department of obstetrics and gynecology at the Women’s Hospital and Health Centre of British Columbia, and colleagues wrote.

Researchers conducted a retrospective, population-based cohort study of women who had a singleton hospital birth in Washington State between Jan. 1, 2004 and Dec. 31, 2013. Of the 743,630 women included, 3.2% were underweight; 47.5% had a normal BMI; and 49.3% of women were overweight or obese. Maternal demographics, gestational medical history, labor and delivery characteristics, as well as congenital anomalies data were collected. The primary outcome was a composite outcome that included complications requiring ICU admission, conditions leading to serious sequelae, life-threatening conditions and maternal death during hospitalization for childbirth.

Researchers found that when compared to women with normal BMI, adjusted ORs for severe maternal morbidity or mortality rates were significantly higher; 1.2 (95% CI, 1-1.3) for underweight women; 1.1 (95% CI, 1.1-1.2) for overweight women and women with class 1 obesity; 1.2 (95% CI, 1.1-1.3) for women with class 2 obesity; and 1.4 (95% CI, 1.3-1.5) for women with class 3 obesity.

Absolute increases in the rates of severe maternal morbidity or mortality were small, with adjusted rate differences of 17.6 (95% CI, 10.5-25.1) per 10,000 overweight women; 24.9 (95% CI, 15.7-34.6) per 10,000 women with class 1 obesity; 28.8 (95% CI, 12.2-47.2) per 10,000 underweight women; 35.8 (95% CI, 23.1-49.5) per 10,000 women with class 2 obesity; and 61.1 (95% CI, 44.8-78.9) per 10,000 women with class 3 obesity.

In a related editorial, Aaron B. Caughey, MD, PhD, of the department of obstetrics and gynecology at Oregon Health and Science University, said that stressing the importance of optimal BMI in women of childbearing age is not enough to reverse “the obesity pandemic.”

“A multifaceted approach that combines the use of technology (eg, cell phone messaging, electronic exercise communities), environmental design, and societal or governmental efforts outside of traditional public health may be needed,” he wrote. “Financial incentives to encourage proper nutrition and exercise also may be useful, such as employers paying for their employees’ gym memberships and providing incentives to those who exercise.” by Janel Miller

Disclosures: The authors report no relevant financial disclosures.