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Weight gain between pregnancies increases risk of gestational diabetes

Studies shows that a weight gain of more than one BMI-unit from first to second pregnancy increases the risk of getting gestational diabetes in the second pregnancy.

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Overweight is an important risk factor for Gestational Diabetes Mellitus (GDM), but researches do not know the underlying mechanisms.

Studies performed at the University of Bergen now suggests that weight gain from the first to the second pregnancy influence the risk of getting GDM in the second pregnancy, independently if the woman is obese or overweight.

Increased risk with low and normal weight

The cohort study includes 24 000 mothers and their two first pregnancies in data from the Medical Birth Registry of Norway in the period 2006 – 2014. Sørbye looked into the change of Body Mass Index (BMI) of the women from the first to the second pregnancy, and found that a weight change of more than one BMI-unit increased the risk of getting gestational diabetes in the second pregnancy.

Surprisingly, the risk increased more strongly if the woman’s was normal weight or underweight at the outset of the first pregnancy:

– Risk increased significantly both for women with BMI below and above 25 at first pregnancy, although more strongly for the former group. Our results suggest weight change as a metabolic mechanism behind the increased risk of GDM, says Sørbøe.

– Promoting healthy weight through the post-partum period should be a target

The risk increased independently of the weight gain during the second pregnancy.

She also found that decreasing BMI with more than two units from the first to the second pregnancy had a preventive effect on gestational diabetes in overweight and obese women:

– This suggests that weight change should be acknowledged as an independent factor for screening GDM in clinical guidelines. Health care costs in mothers with GDM are 25% higher compared to non-diabetic mother, which underlies the importance of promoting healthy weight in the reproductive population. Our results suggest politicians to target healthy weight from preconception through the post-partum period. Today, less than 10 % of countries national policies do this, says Sørbye.

In addition to being a PhD-candidate at the University of Bergen, Linn Marie Sørbye is a midwife at Haukeland University Hospital. The article is published in PLOS Medicine.

Link to article: http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1002367