Women with pre-pregnancy diabetes still face an increased risk of stillbirth, a new study has suggested, despite decreasing stillbirth rates noted among the general population in recent years.

High maternal blood sugar levels and BMI are the biggest risk factors for stillbirth in mothers with diabetes, according to the study, published in the journal Diabetologia. It also found that babies at the lowest and highest weights were more at risk of stillbirth, and the timing of a baby’s delivery was also linked to death.

That’s not to say that diabetic women cannot have healthy babies. The study has led researchers and charities to offer advice for diabetic women – and health professionals – to help minimise the risk of stillbirth in the future.

What Did The Study Find?

Rates of stillbirth were higher among mothers with type 2 diabetes – there were 16.1 stillbirths per 1,000 births among mothers with type 1 diabetes, and 22.9 per 1,000 births in those with type 2. In comparison, there were 4.9 per 1,000 births in the general population.

The authors found that maternal blood glucose level could play a part in stillbirth. Women with type 1 diabetes who suffered 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.

Another significant risk factor for stillbirth in mothers with type 2 diabetes was high maternal BMI. Maternal obesity, the authors note, is itself an independent risk factor for stillbirth, contributing to higher rates of preeclampsia, congenital abnormalities and foetal overgrowth.

Mortality rates were highest for infants born small for their gestational age, however large infants were also at increased risk of death. Timing of delivery could also influence stillbirth. Compared to the general population, an increased risk of stillbirth for women with diabetes is seen at all stages of pregnancy, but previous studies have shown that at full-term the risk is at least five-fold more.

In this study, one third of stillbirths occurred at term with the authors suggesting that earlier delivery seemed a “sensible approach”. However, because of potential issues with early delivery, including respiratory distress syndrome as a result of inadequate lung development, they recommended further research into the issue before recommendations for optimal delivery times are made.

Many medical authorities recommend routine early delivery for mothers with diabetes – recent National Institute for Health and Care Excellence (NICE) guidelines in England, for example, suggest delivery in the 37th or 38th week.

Key Takeaways

The study showed that maternal blood sugar levels and BMI are the main modifiable risk factors associated with stillbirth in women with diabetes.

Dr Emily Burns, head of research communications at Diabetes UK, said “most women with diabetes have healthy pregnancies and healthy babies”, but added that the research reinforces the importance of supporting women to manage their blood glucose levels if they are planning a pregnancy, in order to reduce their risk of complications as much as possible.

“It also suggests that losing extra weight, for women with type 2 diabetes who are overweight, could help to reduce this risk as well,” said Dr Burns.

She called for more research to find better ways of predicting who is most at risk of complications during pregnancy.

“While the likelihood of these complications is still very low, we recommended that anyone concerned should speak to a healthcare professional who can help them to have the best possible chance of a safe pregnancy,” she said.

Birte Harlev-Lam, executive director of professional leadership at the Royal College of Midwives (RCM), said women with existing diabetic conditions require additional monitoring during their pregnancies in line with national guidance.

“There is strong evidence of the risks of obesity and excess weight gain in pregnancy and yet there are no UK guidelines on what constitutes a safe weight gain,” said Harlev-Lam.

“Women should try to be an ideal weight before they become pregnant and, if not, they should follow midwifery advice to exercise and manage their weight in pregnancy whilst maintaining a balanced and nutritious diet.”

Women who require support services should be signposted to appropriate weight management services and social support, Harlev-Lam added.

Meanwhile the study’s authors recommend that “until more accurate assessment of risk during pregnancy becomes available, earlier delivery may be considered an attractive option”.