Researchers have studied the incidence of stillbirth, infant death, preterm birth and pre-eclampsia among pregnant women with type 1 diabetes who gave birth in Norway during the period 1985-2004. The study covers about a third of all births by women with type 1 diabetes in Norway throughout the study period.
Results from the study
The study shows that even in recent years there has been an increased risk of adverse pregnancy outcomes among women with type 1 diabetes. Compared with the general population, the results from the study show that:
- The risk of stillbirth and the risk of perinatal death (foetal death in late pregnancy or death of a child in the first week of life) were about threefold.
- The risk of infant death was doubled.
- The risk of preterm birth (birth before 37 weeks gestation) was quadrupled and the risk of preeclampsia was fivefold.
- The risk of stillbirth and infant death combined fell from the period 1985-1991 to the period 1999-2004. For the latter period, the overall risk was 2.2 per cent, compared with 0.85 per cent in the general population.
Low absolute risk
”It is important to note that the risk of the most serious outcomes is low, even among women with type 1 diabetes,” says Ingvild Eidem, researcher at the Department of Chronic Diseases at the Norwegian Institute of Public Health.
“Norway has a low risk of perinatal death, which means that a tripled risk is still a low absolute risk. However, we had hoped that the risk was lower than our results showed,” says Eidem, who is the primary author of the study published in the journal Diabetologia.
The importance of good pre-natal care
It is well known that good blood sugar control from before the time of conception and throughout pregnancy is important to minimise the risk of adverse pregnancy outcomes. However, information about blood sugar is not included in the registers on which this study is based.
The study shows that the incidence of both preterm birth and pre-eclampsia is high, but the findings from the study suggest that women with type 1 diabetes who experience these risk factors are well taken care of.
”It is important to maintain focus on good pre-natal care for women with type 1 diabetes. Although all goes well for the majority and the risk in Norway is as low or lower compared with other countries, as a group these women still have a higher risk of foetal death and a slightly higher risk of infant death compared with the general population,” says Eidem.
”From a young age, women with type 1 diabetes need information about the importance of pregnancy planning, to ensure good control of their blood sugar from before the time of conception,” adds Eidem.
About the study
Included in the study were women registered in the Norwegian Childhood Diabetes Registry, and the study results are presumed to be representative for the total group of Norwegian women with type 1 diabetes who gave birth during the same period. The diabetes registry is linked with the Medical Birth Registry at the Norwegian Institute of Public Health, which registers the birth outcomes of all births in Norway.
Perinatal and infant mortality in term and preterm births among women with type 1 diabetes. Eidem I., Vangen S., Hanssen KF, Vollset SE, Henriksen T., Joner G., Stene LC
Norwegian Institute of Public Health