(HealthDay)—For some obese women, gestational weight gain (GWG) below that recommended in the current guidelines may be advised to reduce the risk of certain adverse pregnancy outcomes, according to research published online Jan. 18 in Obesity Reviews.

Mufiza Zia Kapadia, M.B.B.S., Ph.D., of McMaster University in Hamilton, Canada, and colleagues conducted a of the literature to assess the risk of adverse associated with GWG below the level recommended in the 2009 Institute of Medicine (IOM) guidelines regarding obese women. The researchers performed a meta-analysis of data from 18 cohort studies.

The researchers found that GWG less than the amount recommended for obese women in the guidelines was associated with higher risk of preterm birth (PTB) (adjusted odds ratio [aOR], 1.46) and small for gestational age (SGA) (aOR, 1.24) and lower risk of large for (LGA) (aOR, 0.77), compared to GWG within the guidelines. GWG less than the recommended amount for also was associated with lower risk for certain adverse pregnancy outcomes, including macrosomia (aOR, 0.64), gestational hypertension (aOR, 0.70), pre-eclampsia (aOR, 0.90), and cesarean birth (aOR, 0.87).

"In summary, our systematic review indicates that obese pregnant women, who gained below the 5 to 9 kg recommended by the IOM guideline had increased risks for PTB (<37 weeks) and SGA (<10th percentile), but decreased risks for LGA (>90th percentile), macrosomia, gestational hypertension, pre-eclampsia, and cesarean birth," the authors write.