Too little or too much weight gain in pregnancy results in adverse maternal and neonatal outcome: Systematic Review and Meta-analysis

Pregnant patients and lactating mothers have always been advised to “Eat for two”, but weight gain more than or less than guideline recommendations puts the mother and baby at high risk for adverse outcomes reports the result of a Systematic Review and Meta-analysis published online June 6, 2017 in JAMA.

The research was conducted by Monash University in Victoria, Australia.

The Institute for Medicine(IOM) released its updated guidelines for gestational weight gain in 2009. The guidelines are individualized according to pre-pregnancy BMI and are independent of age, parity, smoking history, race, and ethnic background. A separate recommendation was made for twin pregnancy.

The recommended gestational weight gain according to BMI are:  gain of 12.5-18 kg for underweight women with BMI <18.5; 11.5-16 kg for normal-weight women with BMI 18.5-24.9; 7-11 kg for overweight women with BMI 25-29.9; and 5-9 kg for obese women BMI ≥30.

In this systematic review and Meta-analysis, Goldstein et al. compared women who gained weight according to IOM guidelines to women who gained more or less than the recommended guideline.

It included 23 studies between January 1, 1999, and February 7, 2017, involving more than a million women (1,309,136) across 10 countries.

Data extraction and analysis showed that about 25% women gained less weight and nearly 50% gained more weight than the recommended allowance.

Women who gained more weight faced 30% (OR=1.30) increased odds of a cesarean delivery as compared to women within the recommended allowance (617 vs 327). The neonates of these women also had nearly twice (OR=1.95) the odds of being born with macrosomia (111 vs 63).

Women who fell below the recommended weight gain were at 53% increased odds of giving birth to small for gestational age infant (OR= 1.53), 70% more odds of having a preterm birth (OR=1.70) and 41% less risk of large for gestational age child ( OR=.59).

In an accompanying editorial Dr Aaron B. Caughey, MD, chair of obstetrics and gynecology at Oregon Health and Science University in Portland writes that this study raises two questions: (1) can clinician offer interventions to patients to change the amount of weight gain during pregnancy, and (2) could altering the weight gain to IOM recommendation improve maternal and neonatal outcome.

Multiple randomized trials have shown that interventions in pregnancy to limit weight gain are effective but the magnitude of effect is very modest and only limited information is available about peripartum gains with not much information available about long term gains for the neonate.

To conclude, mothers and babies do well, with few maternal and neonatal complications if the maternal weight gain is within the recommended limits.

“Basically, it's not about eating for two. For the first trimester, there should be no increased calories, the second trimester is about 330 calories extra a day and third trimester is about 450 calories a day (extra),” said Professor Helena Teede, The Monash researcher and one of the lead author.

"Women also don't need to be 'confined', they need to remain active."

The ACOG committee opinion about weight gain in pregnancy can be accessed here.