Higher risk of perinatal death in women with obesity linked to gestational age
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Women with obesity had a higher risk for perinatal death, which was partly due to lower gestational age at delivery, data published in PLoS One showed.
“Obese women tend to experience worse pregnancy outcomes, including higher rates of neonatal death and stillbirth, but the reasons for this are not fully understood,” Jeffrey N. Bone, MSc, a PhD candidate in the department of obstetrics and gynecology at the University of British Columbia, Canada, told Healio. “We wanted to see if some of this could be explained by their pregnancies ending earlier than women with normal weight.”
Bone and colleagues analyzed 392,820 women in British Columbia who had a singleton birth of at least 20 weeks’ gestation between April 1, 2004, and March 31, 2017, and who had their prepregnancy BMI on record. Among these, 20.6% were overweight and 12.8% were obese.
Perinatal death occurred in 1,834 births (0.5%) and was more common in women with overweight (adjusted OR = 1.22; 95% CI, 1.08–1.37) and obesity (aOR = 1.55; 95% CI, 1.36-1.77).
Women with overweight and obesity had higher rates of preterm birth (8.1% and 9.7%, respectively) compared with women who had a normal BMI (7.3%). Mediation analyses showed that gestational age at delivery accounted for 50.4% of the association between BMI and perinatal death.
“Obese pregnant women require special attention to prevent stillbirth and neonatal death, especially in the second trimester,” Bone said. “The reasons for increased risks are complex, including maternal complications leading to preterm birth that occur more frequently in obese women, as well as fetal and placental reasons. More studies, and more detailed analyses such as these, will be needed to better target interventions to women with high prepregnancy BMI.”
Additionally, Bone suggested future studies also account for limitations of the present study.
“Our study accounted for but did not examine in detail the impact of comorbid conditions such as hypertension and gestational diabetes that can contribute to a higher risk of stillbirth and neonatal death and occur more frequently in obese women,” Bone said. “To increase our understanding of how and why high BMI leads to adverse birth outcomes, we will need to think further about these possible causal pathways and what role specific risk factors play.”