Those complications can be serious and include low blood sugar, malformations and being born either too large or too small, according to the new Italian study.
One obstetrician in the United States wasn't surprised by the findings.
"This study validates what we have known for a long time and have stressed to our patients about diabetes," said Dr Navid Mootabar, chief of obstetrics and gynaecology at Northern Westchester Hospital in Mount Kisco, New York.
"Poorly controlled diabetes can result in poor outcomes during a pregnancy," he said.
For the study, a team led by Dr Basilio Pintuadi, with the Niguarda Ca' Granda Hospital in Milan, analysed the delivery outcomes of pregnant women with either diabetes or gestational diabetes who gave birth to one baby between 2000 and 2012.
After taking the women's age, drug use, and other health issues such as high blood pressure into account, the researchers used computer models to calculate the women's risk for certain complications.
Risk of low blood sugar
The analysis included a total of more than 135,000 pregnancies. Of these, 1,357 of the women developed gestational diabetes, and another 234 had diabetes before they became pregnant.
The pregnancy outcomes of the women with diabetes and gestational diabetes were compared to the pregnancy outcomes of women who didn't have any type of diabetes.
Women with diabetes had a 36 times higher risk for having a baby with low blood sugar, while the risk for women with gestational diabetes was 10 times higher, the study found.
Women with gestational diabetes had a 70 percent higher risk for having either a small or large baby, or an infant with jaundice, the research showed. These women were also roughly twice as likely to require a C-section, or to give birth to a baby with malformations or low levels of calcium and magnesium, the study found.
Meanwhile, women who already had diabetes going into their pregnancy had a nearly six times higher risk for having a small baby and a nearly eight times greater risk for having a large baby, Pintuadi's group reported.
Proper diagnosis essential
These women also had a 2.6 times higher risk for having a baby with jaundice. The risk for malformations was also 3.5 times higher, the risk for low levels of calcium and magnesium was nearly 10 times higher, and the risk for C-sections among women with diabetes was 8.5 times greater, the study found.
The study was observational, meaning that it could only point to associations, and couldn't prove cause-and-effect. The researchers also noted that other health problems, such as high blood pressure and thyroid disorders, are associated with worse pregnancy outcomes.
According to Mootabar, the findings "emphasise the importance of pre-conception care – optimising one's diabetic control prior to getting pregnant, in order to improve outcomes."
Dr Jennifer Wu is an obstetrician-gynaecologist with Lenox Hill Hospital in New York City. She agreed that "babies of diabetics and gestational diabetes face significantly higher risks... Proper diagnosis and observation of these patients is essential and may help to catch an early risk factor."
The study's findings were expected to be presented at the annual meeting of the European Association for the Study of Diabetes (EASD) in Munich, Germany. Findings presented at medical meetings are typically considered preliminary until published in a peer-reviewed journal.
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