Reconsideration of lowering gestational weight gain guidelines in pregnant women diagnosed with gestational diabetes: evidence from a Belgian study.

Background: The suitability of the United States National Academy of Medicine guidelines for gestational weight gain in women with gestational diabetes remains uncertain, raising global concerns. This study aimed to evaluate the association of gestational weight gain with pregnancy and birth outcomes and to determine optimal ranges for gestational weight gain per pre-pregnancy body mass index category in women with gestational diabetes.

Methods: An epidemiological analysis between 2009-2018 analyzed a large Belgian cohort of singleton pregnancies with gestational diabetes and gestational age 38-40 weeks. Multivariate logistic regression assessed associations between gestational weight gain and relevant pregnancy and birth outcomes, with and without adjustment for confounding variables, including maternal age, origin, education, mode of conception, parity, gestational age at delivery, social deprivation, and year of delivery. Potential optimal weight gain ranges were calculated by minimizing the combined risk of small- and large-for-gestational-age infants (SGA, LGA).

Results: A total of 13,060 women with gestational diabetes were included. Compared to recommended weight gain, gestational weight gain above guidelines occurred in 26.9% and was associated with an increased risk of gestational hypertension (aOR 1.41, 95% CI 1.20-1.66, p < 0.001), emergency caesarean section (aOR 1.45, 95% CI 1.25-1.69, p < 0.001), LGA infants (aOR 1.84, 95% CI 1.63-2.08, p < 0.001), and macrosomia (aOR 1.78, 95% CI 1.55-2.04, p < 0.001). Weight gain less than recommended (40.2%) was associated with a decreased risk of gestational hypertension (aOR 0.81, 95% CI 0.69-0.96, p = 0.015), LGA infants (aOR 0.58, 95% CI 0.50-0.66, p < 0.001), and macrosomia (aOR 0.57, 95% CI 0.49-0.65, p < 0.001), but at the expense of an increased risk of SGA infants (aOR 1.68, 95% CI 1.45-1.96, p < 0.001) and low birth weight (aOR 2.28, 95% CI 1.57-3.32, p < 0.001). Based on current analysis, the optimal ranges for gestational weight gain would be 9 to 14 kg for women with a normal weight, 1 to 9 kg for women with overweight, and -7 to 1 kg for women with obesity.

Conclusions: This Belgian study suggests that optimal gestational weight gain for singleton at-term pregnancies complicated by gestational diabetes should be lower than current recommendations, highlighting the need to reevaluate gestational weight gain guidelines in this context.