Lara C. Pullen, PhD

April 29, 2014

CHICAGO — Women who are pregnant with twins are at risk for preterm delivery if they do not gain adequate weight from weeks 20 and 28 of pregnancy, according to results from a retrospective study.

This 8-week gestational window could be an optimal time for nutritional and counseling intervention, suggested Kate Pettit, MD, medical fellow in maternal–fetal medicine at the University of California in San Diego (UCSD). Such an intervention might improve gestational weight gain and potentially decrease the rate of preterm birth.

The retrospective cohort study, presented by Dr. Pettit, was one of a handful of abstracts presented here at the American Congress of Obstetricians and Gynecologists (ACOG) 2014 Annual Clinical Meeting.

The research team reviewed all 489 twin deliveries at UCSD from 2009 to 2013. They obtained gestational weights at less than 14 weeks, 20 weeks, 28 weeks, and at the last visit prior to delivery.

The average patient age was 32.11 years. The twins were the first children for 51.5% of the women; 78.3% of the women were married. Approximately 40% of the patients used assistive reproduction.

The average gestational weight gain was 0.48 kg for the first 20 weeks, 0.65 kg for weeks 20 to 28, and 0.59 kg for the entire pregnancy. A total of 93 women had inadequate gestational weight gain.

Women with inadequate weight gain during weeks 20 to 28 had a higher risk for preterm birth than those with adequate weight gain during this interval (32% vs 14%; P = 0.02). Inadequate weight gain was also associated with a higher risk for spontaneous preterm birth (26% vs 9%; P = .01).

Inadequate gestational weight gain during this period was the strongest predictor of preterm birth before 32 weeks. The mechanism behind this effect is not known.

The study was initiated in response to a 2009 Institute of Medicine (IOM) recommendation for gestational weight gain for twin pregnancies. The report recommends 37 to 54 pounds of weight gain for normal-weight pregnancies, or approximately a pound (0.5 kg) a week of weight gain.

Additional weight gain in obese mothers is not necessary, however, cautioned Raul Artal, MD, professor and chair of the Department of Obstetrics, Gynecology, and Women's Health at St. Louis University in Missouri.

"Additional weight gain can be detrimental in these women," he told Medscape Medical News.

Dr. Artal expressed concern that additional weight gain in overweight and obese women would result in additional insulin resistance, making these women more prone to developing gestational diabetes or worsening of existing diabetes during pregnancy.

He said does not agree with the current IOM guidelines on weight gain during pregnancy. "The Institute of Medicine guidelines for overweight/obese patients, and particularly twin patients, are excessive," he explained.

An ACOG statement issued last year said that if an obese women has a properly growing pregnancy, it is perfectly fine for her to not gain weight.

Dr. Pettit and Dr. Artal have disclosed no relevant financial relationships.

American Congress of Obstetricians and Gynecologists (ACOG) 2014 Annual Clinical Meeting: Abstract 2S. Presented April 28, 2014.


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