Diabetes in pregnancy is associated with increased odds of complications such as caesarean delivery, severe breathing problems and excessive birth weight.
Diabetes in pregnancy (also known as gestational diabetes mellitus) develops when the body produces an insufficient amount of insulin to control blood sugar levels in pregnancy, which can lead to problems for the mother and baby during pregnancy and after birth.
The researcher’s findings illuminated the effects of diabetes in pregnancy and could “contribute to a more comprehensive understanding of the adverse outcomes of pregnancy-related to gestational diabetes mellitus.”
The researchers reported their findings in The BMJ.
Assessing adverse outcomes associated with diabetes in pregnancy
In 2008, a large study assessed the risks of adverse outcomes associated with diabetes in pregnancy, but it did not adjust for some potentially influential factors and additional important pregnancy outcomes were poorly reported, making it difficult to draw firm conclusions.
To address this uncertainty, researchers from Central South University in China analysed data from 156 studies involving over seven million participants that reported complications of pregnancy in women with diabetes.
The studies involved were adjusted to account for one of seven factors:
- Mothers age,
- Pre-pregnancy body mass index,
- Weight gain during pregnancy,
- Number of previous pregnancies,
- Number of previous births,
- Smoking history,
- Chronic high blood pressure.
The researchers categorised the studies by insulin use to address the effect of different severities of diabetes during pregnancy. Following this, they performed analyses based on whether the country was developed or developing, the quality of the study, diagnostic criteria and the screening method used.
Increased risk of adverse consequences
The team found that in studies with no insulin when adjusted for the seven factors, women with diabetes in pregnancy had increased odds of the following outcomes: caesarean section, preterm delivery, low one minute Apgar score (a measure of an infant’s condition at birth), excess birth weight, and an infant born large for gestational age than those without diabetes.
Contrastingly, studies with insulin use involved meant that women with diabetes in pregnancy had odds of having an infant large for gestational age or with respiratory distress syndrome, neonatal jaundice or requiring neonatal intensive care admission.
They found no clear differences in the odds of other outcomes such as instrumental delivery, heavy bleeding following birth, stillbirth, neonatal death or low birth weight between women with and without diabetes in pregnancy, even after adjusting for confounders.
The observational nature of the study means that a definite cause cannot be established, and the researchers cannot rule out the possibility that other unmeasured factors may have affected their results.
Nevertheless, this is the most in-depth analysis of its kind to date, which the researchers said: “contributes to a more comprehensive understanding of adverse outcomes of pregnancy-related to gestational diabetes mellitus.”
As such, they concluded: “These findings support the need for an improved understanding of the pathophysiology of gestational diabetes mellitus to inform the prediction of risk and for precautions to be taken to reduce adverse outcomes of pregnancy. Future primary studies should routinely consider adjusting for a more complete set of prognostic factors.”