Insulin use has a protective effect on the fetus of women with Gestational Diabetes Mellitus (GDM), Australian research shows.
A retrospective study of neonatal outcomes for 1857 women with GDM managed at a Sydney hospital showed that insulin use was associated with significantly lower rates of infant resuscitation after caesarean delivery.
The review involved women with GDM who had term (≥37 weeks) pregnancies delivering between 2005 and 2014.
About 30% of women had insulin treatment, and these women had a higher BMI (31.2 vs 29.0 kg/m2 ) and higher rates of preeclampsia (7.3% vs 4.1%) and a significantly shorter gestational period (38.7 vs 39.2 weeks) than women who did not receive insulin.
Women treated with insulin for GDM also had significantly lower rates for infant resuscitation (21.2 vs 28.6%, P = 0.001) compared to those who did not.
After adjusting for other factors, women with GDM treated with insulin had 31% lower risk of resuscitation (OR = 0.69, P = 0.004).
Other factors that independently predicted need for resuscitation included higher gestational age (OR = 0.88) and emergency caesarean (OR = 2.33).
The study authors from the Nepean Hospital, Penrith, said that with increasing rates of obesity and GDM, complications such as macrosomia have led to an increase in rates of caesarean delivery for infants and need for resuscitation.
However until now there has been limited data on the influence of insulin use on outcomes for neonates delivered via caesarean section.
They speculated that insulin is effective in nullifying the negative impacts of poor glycemic control seen in women with GDM despite dietary and lifestyle interventions.
“With poorer control of in vitro maternal glucose levels, the infant’s immature endocrinological system copes by either reducing endogenous glucose production or increasing peripheral glucose uptake,” they wrote in the Journal of Diabetes.
“The physiological stress also leads to increased secretion of counter-regulatory hormones. This results in poorer birth outcomes and the need for resuscitation.”
And since insulin does not pass through the placenta from mother to fetus directly, it may be acting secondarily by decreasing excess nutrient availability from the mother to the infant.
This may also explain insulin’s lower risks as compared to anti-hyperglycaemics, they added.
Further studies are needed to investigate the role, dosage, and criteria for insulin use in women with GDM, they said, as well as the influence of post-insulin administration glycaemic levels in reducing poor foetal outcomes.