Obesity in pregnancy: Risks and interventions by gestational stage

Research has also linked infant birth weight to maternal weight. Studies have shown the incidence of macrosomic infants (birth weight of at least 4,000 g) to be higher in obese women, even in the absence of antenatal complications.^19,25,36 Specifically, Gross et al¹⁹ concluded that the increase in macrosomic and large-for-gestational-age infants (defined as over 90% of weight for gestational age) born to obese mothers cannot be explained by the presence of maternal diabetes. They noted that the frequency of macrosomia was 15.1% and large-for-gestational-age was 31% among obese patients, while the incidence of diabetes mellitus was only 9%. However, Perlow et al³⁵ demonstrated that the increased rate of macrosomia disappeared if patients with preexisting medical conditions were excluded.

Studies also have shown that newborns of obese patients have weight problems as they age. Edwards et al²⁷ noted that at 1 year, infants of obese mothers were significantly more overweight than those of controls. Specifically, 47% of the infants of obese mothers were above the 75th percentile for weight-length, compared to 22% in the control group.

Counsel weight reduction

Obesity is a major health risk for both the general and obstetric populations. Fortunately, this risk can be addressed through lifestyle modification. Though we lack studies demonstrating improved peripartum outcomes with weight reduction, there is no reason to doubt that weight loss will decrease the rate of adverse events. Ob/Gyns caring for obese patients should inform these women of the unfavorable pregnancy outcomes secondary to excessive weight and encourage preconception weight control.

The authors report no financial relationship with any companies whose products are mentioned in this article.