New research published in Diabetologia (the journal of the
European Association for the Study of the Diabetes [EASD]) shows an
increased risk of adverse outcomes in babies born to mothers with
gestational diabetes, when compared to others.
- included all 796,346 deliveries taking place after 22 weeks in
France in 2012
- contained 57,629 (7.24%) mothers with GDM
- had available data linking the mother to the child for
705,198 deliveries (88% of the total)
- noted that insulin was used to treat 25% of mothers with
serious or hard to control GDM.
The authors adjusted their data, limiting the analysis to
deliveries after 28 weeks to ensure all women diagnosed with GDM
were included (since diagnosis of GDM in most cases takes place at
or after 28 weeks).
Findings for deliveries after 28 weeks
The increased risk of various complications for mothers with GDM
versus mothers without GDM were:
- preterm birth 30%;
- Caesarean section 40%;
- pre-eclampsia/eclampsia 70%;
- babies born significantly larger than average size (macrosomia)
- respiratory distress 10%;
- birth trauma 30%;
- and cardiac malformations 30%.
While these increased risks combine women with both insulin- and
diet-treated GDM, most of the increased risk was found in women
with insulin-treated GDM. This is because diabetes is more serious
and blood glucose more difficult to control in women who need
insulin treatment, resulting in a higher risk of complications than
in those women treated with diet only.
The researchers then limited the analysis to normal-term
deliveries (37 weeks), showing an increased risk of death of the
newborn baby in women with GDM.
After excluding women suspected to have undiagnosed T2D before
pregnancy, the researchers noted:
- a moderate increased risk of the baby dying for those women
with diet-treated GDM (possibly because the unborn child is exposed
to higher glucose levels for longer)
- increased risk of cardiac malformations for women with
- decreased risk of nervous system malformations: one hypothesis
is that early exposure of the embryo to abnormally high glucose
levels has different effects on cardiac and nervous system
The study conclusion: "We have clearly demonstrated that GDM is
a disease related to adverse pregnancy outcomes and that most of
the risks are higher in women with insulin-treated GDM. By
restricting analysis to deliveries after 37 weeks and excluding
cases of type 2 diabetes that were undiagnosed before pregnancy, we
identified a moderate increase in risk of death to the newborn baby
in women with GDM treated with diet only. Although more
investigation is needed, this study helps illuminate the
controversy about timing of delivery in GDM pregnancy."
The study is by Dr Sophie Jacqueminet, Pitié-Salpêtrière
Hospital, Assistance Publique - Hôpitaux de Paris (AP-HP), France;
Professor Delphine Mitanchez, Armand Trousseau Hospital, AP-HP,
Paris, France; and Cécile Billionnet, French National Health
Insurance, Paris, France, and colleagues.