Pregnancy Complications More Likely in Women with Anorexia Nervosa: finds Study

The study, published in the American Journal of Obstetrics and Gynecology, reveals that anorexia nervosa during pregnancy is associated with several significant adverse outcomes. These include a higher likelihood of preterm birth, low birth weight, and other complications that can affect both the mother and the baby. However, adjusting for factors such as anxiety, depression, substance use, and smoking during pregnancy reduces but does not eliminate this risk.

Moreover, a significant portion of the increased risk of adverse outcomes was attributed to an underweight body mass index (BMI) before pregnancy, while an even greater proportion of the risk was linked to inadequate gestational weight gain.

Previous research on the link between anorexia nervosa and adverse pregnancy outcomes has produced varied results. Considering this, Rebecca J. Baer, California Preterm Birth Initiative, University of California San Francisco, San Francisco, CA, and colleagues aimed to examine the link between anorexia nervosa and adverse live-born pregnancy outcomes by using adjustment modeling to account for confounding factors. Additionally, it included a mediation analysis to assess how underweight pre-pregnancy body mass index and inadequate gestational weight gain contribute to these outcomes.

The study analyzed data from California live-born singletons between 2007 and 2021, using birth certificates and linked hospital discharge records to identify pregnancies with anorexia nervosa via ICD codes. It assessed a range of adverse pregnancy outcomes, including gestational diabetes, preeclampsia, and preterm birth, using Poisson regression models to calculate risks. These risks were first analyzed unadjusted, then adjusted for demographic factors, and further refined to account for anxiety, depression, substance use, and smoking. Mediation analysis was conducted to determine how much of the risk was influenced by underweight pre-pregnancy BMI and inadequate gestational weight gain.

The study led to the following findings:

• The sample included 241 pregnant people with a diagnosis of anorexia nervosa and 6,418,236 pregnant people without an eating disorder diagnosis.
• A diagnosis of anorexia nervosa during pregnancy was associated with many adverse pregnancy outcomes in unadjusted models (relative risks ranged from 1.65 [preeclampsia] to 3.56 [antepartum hemorrhage]) in comparison with people without an eating disorder diagnosis.
• In the final adjusted models, birthing people with an anorexia nervosa diagnosis were more likely to have anemia, preterm labor, oligohydramnios, severe maternal morbidity, a small for gestational age or low-birthweight infant, and preterm birth between 32 and 36 weeks with spontaneous preterm labor (adjusted relative risks ranged from 1.43 to 2.55).
• Underweight prepregnancy body mass index mediated 7.78% of the excess in preterm births and 18.00% of the excess in small for gestational-age infants.
• Gestational weight gain below the recommendation mediated 38.89% of the excess in preterm births and 40.44% of the excess in low-birthweight infants.

"The findings are crucial for clinicians managing patients with anorexia nervosa. Addressing anorexia nervosa along with any comorbid conditions and providing guidance on preconception weight and gestational weight gain can potentially enhance pregnancy outcomes for individuals with this disorder," the researchers concluded.

Reference:

Baer, R. J., Bandoli, G., Jelliffe-Pawlowski, L. L., Rhee, K. E., & Chambers, C. D. (2024). Adverse live-born pregnancy outcomes among pregnant people with anorexia nervosa. American Journal of Obstetrics and Gynecology, 231(2), 248.e1-248.e14. https://doi.org/10.1016/j.ajog.2023.11.1242