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Timing of excessive gestational weight gain influences infant size

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August 30, 2017

Leanne Redman
Leanne M. Redman

Excessive gestational weight gain in the first and second trimester of pregnancy among Chinese mothers is associated with an increased risk for infants born large for gestational age, independent of maternal prepregnancy BMI, according to study findings published in Obesity.

“Maternal obesity and weight gain in pregnancy are two well-documented risk factors for rapid weight gain and obesity development in children,” Leanne M. Redman, PhD, FTOS, associate professor at Pennington Biomedical Research Center in Baton Rouge, Louisiana, told Endocrine Today. “Our study in over 16,000 well-characterized women throughout pregnancy shows that not all weight gain in pregnancy is equal. We found that weight gain that occurs in pregnancy from conception up until week 24 exerts the most potent effect on the size of the infant at birth, regardless of the weight gain that occurs later.”

Redman, Nicholas T. Broskey, PhD, a postdoctoral fellow at Pennington Biomedical Research Center,and colleagues analyzed electronic health records from 16,218 mother-child pairs in the Women and Children’s Health System of Tianjin, China, between June 2009 and May 2011. Total gestational weight gain was calculated as the difference between prepregnancy and delivery weight. Second trimester weight gain, considered as “early gestational weight gain,” was defined as the difference between the first measured weight recorded in the first trimester and the weight measured between 24 and 27 weeks’ gestation; third trimester weight gain, considered “late gestational weight gain,” was calculated as the difference between weight measured at 24 to 27 weeks’ gestation and weight measured at 32 to 36 weeks’ gestation. Researchers defined adequacy of gestational weight gain for each woman according to Chinese prepregnancy BMI classifications (overweight BMI, between 24 kg/m² and 28 kg/m²; obese BMI, at least 28 kg/m²) and the 2009 Institute of Medicine (IOM) recommendations.

Within the cohort, 64% of mothers had normal prepregnancy weight; 12% had underweight; 18% had overweight; 6% had obesity. According to IOM guidelines, 75% of the women experienced excessive gestational weight gain in early pregnancy; 77% experienced excess gestational weight gain in late pregnancy.

Researchers found that infants born to mothers with adequate early gestational weight gain were 50% less likely to be large for gestational age compared with infants born to mothers with excessive early gestational weight gain (OR = 1.5; 95% CI, 1.3-1.9). Infants born to mothers with obesity were three times more likely to be born large for gestational age (OR = 3; 95% CI, 2.5-3.6) when compared with infants born to mothers with overweight (OR = 1.7; 95% CI, 1.5-1.9) or underweight (OR = 0.34; 95% CI, 0.3-0.4).

Infants born to mothers with excess gestational weight gain in both early and late pregnancy had the highest risk for being born large for gestational age, according to researchers (OR = 2.4; 95% CI, 1.5-4.0). Infants born to mothers who had excessive early gestational weight gain, followed by inadequate gestational weight gain had a reduced risk for being born large for gestational age (OR = 1.9; 95% CI, 1.1-3.2) as did infants born to mother with excessive early gestational weight gain followed by adequate late gestational weight gain (OR = 1.7; 95% CI, 1-3).

The researchers noted that, regardless of prepregnancy BMI, a U-shaped association between early gestational weight gain and infant birth weight was evident, and the same findings were observed for macrosomia and low birth weight.

“Because this period of pregnancy could influence the development of increased adiposity in the child, this is the opportune time to initiate lifestyle interventions in pregnant women,” the researchers wrote. “Data on unintended pregnancy in the United States suggest approximately 49% of pregnancies are unplanned, and therefore capturing couples who are planning pregnancy is a critical strategy for public health programs targeting intergenerational obesity prevention.”

In commentary accompanying the study, Cheryce L. Harrison, PhD, a research fellow at the School of Public Health and Preventive Medicine at Monash University in Victoria, Australia, said the study results add evidence to a growing realization that interventions aiming to optimize gestational weight gain need to occur very early in pregnancy.

“Proposed avenues for future action include improving the focus on primary care and maternal child health when women may be more engaged, especially between pregnancies, as well as increasing integration within health systems and shifting away from traditional education-focused information,” Harrison wrote. “Given the vital need to address and arrest the cycle of increasing weight gain and adverse health, early intervention prior to pregnancy should be at the forefront of public health efforts moving forward to optimize maternal and neonatal adverse health both during and following pregnancy.” – by Regina Schaffer

Disclosures: The authors and Harrison report no relevant financial disclosures.