Interpregnancy weight gain linked to elevated gestational diabetes risk
Weight gain between pregnancies may increase a woman’s risk of developing gestational diabetes mellitus (GDM) in a subsequent pregnancy, suggests an observational study from Norway.
“The risk of GDM in second pregnancy increased with increasing weight gain between pregnancies,” said the researchers. “Antenatal guidelines for monitoring GDM in pregnancy should add interpregnancy weight change as an independent risk factor for GDM.”
“Efforts ... targeting women who are overweight in pregnancy and childbirth should expand in focus to promote healthy weight from preconception throughout reproduction,” they said.
Compared with women who maintained a stable BMI between pregnancies (-1 to 1 kg/m2 change), weight gain between pregnancies was associated with an elevated risk of developing GDM in the second pregnancy, with a twofold risk in women with a 1 to <2 kg/m2 and 2 to <4 kg/m2 increase (adjusted relative risk [adjRR], 2.0 and 2.6, respectively) and a fivefold risk in women with a ≥4 kg/m2 increase (adjRR, 5.4). [PLoS Med 2017;14:e1002367]
The association between interpregnancy weight gain and increased GDM risk was observed in women who were normal-weight or overweight during their first pregnancy (<25 and ≥25 kg/m2, respectively). However, the risk was particularly evident in women with BMI <25 kg/m2 during their first pregnancy. Women whose BMI was ≥25 kg/m2 during their first pregnancy and reduced by ≥2 kg/m2 before their second pregnancy had a lower risk of GDM during the second pregnancy (adjRR, 0.4).
“[This] possible preventive effect on GDM of losing weight between pregnancies in overweight women needs to be replicated in other studies,” said the researchers.
GDM prevalence increased with rising prepregnant BMI during the second pregnancy (ptrend <0.001) and the association between weight gain between pregnancies and GDM risk was stronger in women with an interval of <24 months between pregnancies compared with an interval ≥24 months (p=0.001).
This study was done using data from the Medical Birth Registry of Norway, and involved 24,198 women whose first two pregnancies took place between 2006 and 2014.
“Results from our study suggest that increasing weight between first and second pregnancy, during a relatively short time … may stress the glucose metabolism and cause a subclinical decreased insulin sensitivity among normal-weight women as well as overweight women,” said the researchers.
“We suggest that an additive effect of the physiological decrease in insulin sensitivity during pregnancy may overload the capacity and increase the susceptibility to develop GDM, especially in normal-weight women who are used to higher insulin sensitivity,” they said, while acknowledging potential bias and confounding as study limitations.