Mothers with pre-pregnancy diabetes at increased risk of stillbirth.
Mothers with diabetes are at a four to five times increased risk of stillbirth, according to a new study.
Researchers at the University of Glasgow found that high maternal blood sugar levels and BMI (body mass index) are risk factors for stillbirth, with babies at the lowest and highest weights being most at risk.
The results of the study, recently published in Diabetologia, found that there was no improvement seen over recent years to the findings, in contrast with decreasing stillbirth rates seen in other areas of research on pregnancy.
Researchers found that the level of the mother’s blood sugar was a key risk factor for increased risk of stillbirth.
The results reported that the majority of stillbirths in mothers with diabetes happened before 37 weeks and researchers said finding better ways of detecting babies at risk would be critical.
It was also found that one third of stillbirths in mothers with diabetes happened close to term and could be influenced by policy on delivery.
Recognised risk factors for stillbirth that can be modified in the general population include maternal obesity, advanced maternal age and smoking, in addition to restricted foetal growth.
This study was carried out by Dr Robert Lindsay and Dr Sharon Mackin, of the Institute of Cardiovascular and Medical Sciences at the University of Glasgow, UK and colleagues, who analysed figures from mothers diagnosed with pre-pregnancy diabetes to help define maternal and foetal characteristics associated with stillbirth.
Timing of stillbirth was also analysed to examine the potential for strategies around routine delivery.
The study, conducted over an 18-year period, included 5,392 babies born to 3,847 mothers with diabetes – with 3,778 offspring to 2,582 mothers with type 1 diabetes; 1,614 offspring to 1,265 mothers with type 2 diabetes.
Stillbirth rates recorded were 16.1 per 1,000 births in type 1 and 22.9 per 1,000 births in type 2, compared with 4.9 per 1,000 births in the general population.
Women with type 1 diabetes who had stillbirth were seen to have higher average blood glucose levels at all stages of pregnancy.
For type 2 diabetes, a different pattern was noted – in that pre-pregnancy blood glucose levels, rather than levels during pregnancy, appeared to be a more important predictor of stillbirth.
The authors noted that in clinical practice, where input on blood sugar control as part of pre-pregnancy counselling would be of particular importance to mothers with type 2 diabetes, the uptake of such counselling is generally lower than in type 1 diabetes.
They added that “overall efforts to improve blood glucose levels before and during pregnancy remain central.”
Another risk factor for stillbirth in mothers with type 2 diabetes was high maternal BMI.
There are limited existing reports on pregnancies complicated by diabetes.
Previous studies found that poor maternal blood glucose levels, blood complications and poor preparation for pregnancy were linked with stillbirth in mothers with diabetes.
However, traditional risk factors noted in the general population were less well documented for mothers with the condition.
This study was carried out by Dr Robert Lindsay and Dr Sharon Mackin, of the Institute of Cardiovascular and Medical Sciences at the University of Glasgow, UK and colleagues, who analysed figures from mothers diagnosed with pre-pregnancy diabetes to help define maternal and foetal characteristics associated with stillbirth. Timing of stillbirth was also analysed to examine the potential for strategies around routine delivery.
Researchers concluded that maternal blood sugar levels and BMI were the main modifiable risk factors associated with stillbirth in women with diabetes.
Mortality rates are highest for infants born small for their gestational age, but large infants are also at increased risk.
The study authors said: “Achievement of near normal blood sugar levels remains key to reducing risk.
“As stillbirth risk is high at full term we recommend that until more accurate assessment of risk during pregnancy becomes available, earlier delivery may be considered an attractive option.”