Mothers who suffer from pre-existing diabetes during their pregnancy face a risk of stillbirth and infant death that is more than four times greater than women who do not carry the disease, a new study finds.

Published in Diabetologia (the journal of the European Association for the Study of Diabetes), the study is the first in a long line of prior studies investigating maternal diabetes to exclude birth defects as possible causes of stillbirth and, later, infant death. Researchers suggest that mothers who go into their pregnancy with the popular insulin deficiency are 4.56 times more likely to have their unborn fetus die than mothers without it. Infant death (i.e. death occurring within in the child’s first year of life) is 1.86 times more likely.

Researchers from Newcastle University, South Tees NHS Trust, U.K., and Public Health England, collaborated on an analysis of all normally formed singleton offspring of women with pre-existing diabetes (1,206 with type 1 diabetes and 342 with type 2 diabetes). The relative risks of fetal death and infant death were estimated by comparison using the population data from the Northern Perinatal Morbidity and Mortality Survey. The team found that the prevalence of fetal death in women with diabetes was three percent, compared to 0.7 percent in women without diabetes. Infant death increased from 0.4 percent to 0.7 percent when the disease was introduced.

Diabetes results from an overabundance of glucose (i.e. blood sugar) in the bloodstream. This is often the effect when a person’s body doesn’t produce enough insulin, a hormone secreted in the pancreas, that regulates blood sugar. Pregnant women face an increased risk for complicating their birth, because the placenta that delivers nutrients to the developing fetus mistakenly overloads the fetus with glucose. This causes an overproduction of insulin and actually induces hypoglycemia (i.e. low blood sugar), which can be life-threatening for the child.

Pregnant women who have diabetes are often advised to take folic acid in order to reduce their risk for fetal complications such as spina bifida and cleft lip. “These are available on prescription and should be taken for at least three months before conceiving,” the researchers said in a statement. “Our results suggest this simple action may also help to reduce the risk of stillbirth or infant death even in babies without these conditions."

The researchers also looked at the mothers’ glycated hemoglobin levels, a marker that can reliably track glucose levels in the women’s bloodstream over the course of the study. A healthy level, according to the American Diabetes Association, is seven percent. Meanwhile, England's National institute for Health and Care Excellence (NICE) has set a target of 6.1 percent. The team found women in their study had an average glycated hemoglobin level of 7.8 percent. Had the women attained safe levels, the researchers argue, they would have reduced their risks by 40 percent.

“It's disappointing to see so little improvement because, with the right care, most women with diabetes can — and will — have a healthy baby,” they explained. “Stillbirths and infant deaths are thankfully not common, but they could be even less common if all women with diabetes can be helped to achieve the best possible control of their blood glucose levels.”

The team urged pregnant women and women with diabetes who anticipate pregnancy to regularly check their blood glucose levels. Any increase can have detrimental effects on the developing fetus, even into its first year of life.

"If you are planning a pregnancy, and your blood glucose levels are high, then any reduction — even a small one — is likely to be good for your baby,” they said. “Secondly, seek advice as early as possible from your diabetes team. They can help you keep your glucose at safe levels, as neither high blood glucose nor repeated episodes of severe hypoglycemia are good for you or your baby."

Source: Tennant PWG, Glinianaia SV, Bilous RW, Rankin J, Bell R. Pre-existing diabetes, maternal glycated haemoglobin, and the risks of fetal and infant death: a population-based study. Diabetologia. 2013.