Gestational Diabetes and Congenital Heart Defects

Health Writer

Every woman who is pregnant will tell you that she "just wants a healthy baby." If you have diabetes and get pregnant, then it's important to control blood sugar levels. If you develop gestational diabetes during pregnancy, then it's crucial to institute measures to control blood sugar levels. A 2017 study reveals that keeping blood sugar levels in check may help prevent serious heart conditions in children.

The research, published in the journal eLife, involved using human embryonic stem cells to grow heart muscle cells (cardiomyocytes) in the lab. These cells were then exposed to different levels of glucose. The cardiomyoctyes exposed to lower levels of glucose developed normally. Those that were mixed with higher levels of glucose either matured late, or failed to mature at all, instead nudging the development of more immature cells. The mechanism seemed to be a prodding of excess "building blocks" in the heart muscle cells, by the presence of high levels of sugar, which kept the cells from maturing completely. That phenomenon appeared to be linked to congenital abnormalities.

Though genetics play a substantial role in the development of congenital heart disease, the leading non-genetic cause is having diabetes or high blood sugar levels during pregnancy. In fact, babies born to mothers with high levels of blood sugar during gestation are two to five times more likely to develop congenital heart disorders, compared to babies born to women with no blood sugar issues. Until this new research, the mechanism causing this risk was not clear. During one phase of the study, the researchers noted that the fetuses of pregnant mice with diabetes had heart cells that divided quickly but "matured slowly." It is the slow maturation of these cells that was directly associated with the congenital heart abnormalities.

If you already have diabetes when you become pregnant then it is crucial that you work with your obstetrician and a team that may include a dietician, diabetes educator, and endocrinologist in order to tightly control blood sugar levels.

It's also important to be aware of risk factors for gestational diabetes, which is diabetes that occurs during pregnancy. Certain hormonal fluctuations (cortisol, growth hormones, estrogen, progesterone, human placental lactogen, placental insulinase) contribute to fluctuating and elevated blood sugar levels, so it's important to limit any risk factors that can further sustain blood sugar elevations. Those risk factors include eating more, exercising less, and having a diagnosis of obesity. Other risk factors that can contribute to a higher risk of developing gestational diabetes include:

  • Having a family history of diabetes
  • Having been diagnosed with prediabetes
  • Having polycystic ovarian syndrome
  • Having a previous unexplained stillbirth or miscarriage
  • Having a previous baby that weighted over nine pounds
  • Being an older mother

Current statistics suggest that nearly one in one hundred children in the U.S. are born with congenital heart disease. That makes it the most common birth defect. Severity can range from a mildly weakened heart to severe heart deformities that require surgery.

This new understanding of the role that sustained elevated blood sugar can have on the developing fetus will hopefully inspire women planning a pregnancy or happily discovering that they are pregnant to make every effort to maintain optimal health during those nine months to support the health and development of their growing baby. Blood sugar control is incredibly important in that equation.

Having a discussion with your doctor before a planned pregnancy can be incredibly helpful, identifying the challenges that the pregnancy may present if you have diabetes or prediabetes or another high-risk condition like obesity. You can strategize to make sure you have tight control of blood sugar and to plan how you will tackle diet and exercise to limit this and other risks to your growing baby. If you find yourself pregnant unexpectedly, reach out to your doctor quickly to establish best health practices.

It's worth sharing that the researchers isolated a very specific pathway ― the pentose phosphate pathway ― responsible for cardiac cell maturation during the research, and have applied for a provisional patent, so that they can continue to explore ways to create a treatment to prevent congenital heart abnormality.

See more helpful articles:

10 Ways to Have a Healthy Pregnancy with Diabetes

Obesity, Diabetes in Pregnancy Can Mean Dangerously Large Baby