Clinical Health Updates

Obesity associated with increased risk of stillbirth

Clinical Question:
Is maternal obesity associated with an increased risk of stillbirth?

Bottom Line:
Maternal obesity is associated with double the risk of stillbirth. This study did not provide information regarding absolute risk. Neither did it evaluate to what extent this association may be explained by other known risk factors for adverse perinatal outcomes that are frequently seen in obese women, such as hypertension and diabetes.

Reference:
Chu SY, Kim SY, Lau J, et al. Maternal obesity and risk of stillbirth: a metaanalysis. Am J Obstet Gynecol 2007;197(3):223-228.

Study Design:
Meta-analysis (other)

Synopsis:
The authors conducted this metaanalysis to summarize the available epidemiologic evidence on the relationship between maternal overweight and obesity and the risk of stillbirth. They identified studies from 3 sources:
(1) a PubMed search of relevant articles that were published between January 1980 and September 2005
(2) reference lists of publications that were selected from the PubMed search
(3) reference lists of review articles on obesity and maternal outcomes that were published between 2000 and 2005.
The investigators used a Bayesian random effects model to perform the metaanalysis and metaregression. Nine studies were included in the metaanalysis. The unadjusted odds ratios of a stillbirth were 1.47 (95% CI, 1.08-1.94) and 2.07 (95% CI, 1.59-2.74) among overweight and obese pregnant women, respectively, compared with normal-weight pregnant women. The metaregression analysis found no evidence that these estimates were affected by selected study characteristics. Maternal obesity is associated with an increased risk of stillbirth, although the mechanisms to explain this association are not clear.