A research team reviewed published scientific studies to find evidence of the long-term effects on offspring born to mothers who had diabetes while they were pregnant.
Their review found studies in which women with diabetes had offspring with an increased incidence of obesity and diabetes as children and adults. The evidence for the effect of diabetes during pregnancy on learning and understanding abilities later in life was less conclusive.
"Talk to your obstetrician about controlling diabetes during pregnancy."
Abigail Fraser, PhD, and Debbie A. Lawlor, MSc, PhD, MPH, from the MRC Integrative Epidemiology Unit and School of Social and Community Medicine at the University of Bristol in Bristol, UK, conducted this scientific review.
These researchers found several published studies in which effects on body size and occurrence of type 2 diabetes were seen in children and/or adults whose mothers had diabetes while pregnant. Type 2 diabetes is a disease that affects the metabolism of sugar. Patients with type 2 diabetes have high blood sugar. They do not lack insulin, but their body's own insulin is less effective at lowering blood sugar.
Drs. Fraser and Lawlor found one study of the Pima Indians of Arizona that showed that increased body size, increased fasting blood sugar and insulin and type 2 diabetes were more common in offspring of mothers who had diabetes during their pregnancy than in offspring of mothers who did not have diabetes.
A study of 280,866 Swedish families showed that men whose mother had diabetes during their pregnancy had a body mass index (BMI) about 1 unit higher than their brothers who were born before their mother got diabetes. BMI is a measure of obesity where 18.5 to 25 is normal, 25 to 30 is overweight and 30 and above is obese.
Reviews of studies on the learning and thinking abilities of offspring born to mothers who had diabetes during the pregnancy showed mixed results.
In a Swedish study of 6,397 offspring of mothers with diabetes during pregnancy, the children had a 25 percent increased chance of not completing school through age 16 compared to children whose mothers did not have diabetes.
A study done in the UK showed children born to a mother with diabetes during pregnancy had lower school entry scores at age 4, lower IQ at age 8 and lower school test results at age 16 compared to children born to mothers without diabetes.
In contrast to those studies, other studies have shown better brain functioning of offspring born to women with diabetes during pregnancy.
One study showed that 10-year-old children of mothers who had diabetes scored higher on thinking tests than offspring of women without diabetes. Another study showed that higher blood sugar in mothers was associated with a later higher IQ in offspring.
"A woman who has diabetes before becoming pregnant or who develops diabetes during the pregnancy is at increased risk for delivering a baby with significant medical problems," said Andre Hall, MD, who practices obstetrics and gynecology at Birth & Women's Care in Fayetteville, NC. "In addition, poorly controlled diabetes has been associated with late term unexplained stillborn and birth trauma. Birth defects are also more common in moms with diabetes."
Drs. Fraser and Lawlor theorized that increased blood sugar levels during pregnancy could affect developing organs in the fetus, such as the pancreas, which controls blood sugar and the brain. A pregnant mother’s diabetes also could affect the body’s processing of blood sugar and release of insulin and that, in turn, could influence body fat accumulation in the infant and possibly later in life.
One possible explanation the authors gave for long-term effects of diabetes during pregnancy on offspring was that the mother’s increased blood sugar could change the environment that the baby’s genes were exposed to. Changes in the genes’ environment have been shown to affect the way genes act later, and that can mean changes in the body’s normal processes and functions.
"The take home message [of this study] is that moms that are diagnosed with diabetes should pay close attention to their diet and follow their medical provider's recommendations for treatment," Dr. Hall told dailyRx News.
The review was published in the May issue of Current Diabetes Reports.
The authors declared no conflicts of interest.
Dr. Fraser is funded by a UK Medical Research Council fellowship.