Sinai Health Magazine

Fall 2019 | The Changing Face of Diabetes

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Carolyn Christo

Gestational Diabetes

Carolyn Christo is a Registered Dietitian and Certified Diabetes Educator within the Leadership Sinai Centre for Diabetes.

Q: What is gestational diabetes and what causes it?

CC: Gestational diabetes is a form of diabetes that develops during pregnancy. During the second half of pregnancy (starting around 24 to 28 weeks) the placenta makes hormones that are necessary for the growth of the baby. These hormones interfere with how insulin in the body works. Due to the “insulin resistance” caused by pregnancy hormones, the pancreas has to make more insulin to keep the blood sugar levels in a normal range. Gestational diabetes develops when the pancreas cannot make enough insulin to keep up with the pregnancy hormones.

Q: Will it go away after pregnancy?

CC: In the majority of cases, yes. Once the baby is born and the placenta is delivered, hormone levels adjust, thereby decreasing insulin resistance and allowing blood sugar levels to return to normal. In rare cases, the blood sugar levels remain high and a woman receives a diagnosis of pre-diabetes or type 2 diabetes. It is very important that all women who have had gestational diabetes take a two-hour oral glucose tolerance test to confirm blood sugar levels have returned to normal. This test can be done anytime between six weeks and six months after delivery.

Q: If I have gestational diabetes for one pregnancy, will I have it for future pregnancies?

CC: Having gestational diabetes in one pregnancy increases your risk of having it in future pregnancies. The recurrence rate of gestational diabetes is 30 to 84 per cent.

Q: Will gestational diabetes affect my baby’s health or development?

CC: It can. If blood sugar levels are untreated and remain high during pregnancy the baby will get the extra sugar and will grow bigger. A big baby may mean a more difficult delivery and higher risk of shoulder dystocia, a complication of delivery in which the baby’s shoulders become stuck in the pelvis. Other risks for the baby include jaundice and hypoglycemia (low blood sugar) following delivery.

Q: Are there long-term implications for my or my baby’s health?

CC: Women who develop gestational diabetes in pregnancy are unfortunately at greater risk of developing type 2 diabetes in the future.

Research has also shown that babies born to mothers who have had gestational diabetes are at greater risk of becoming overweight or obese as young adults, and are at greater risk of developing impaired glucose tolerance or pre-diabetes as they grow older.

Breastfeeding immediately after delivery and for at least three to four months can help reduce these health risks.

Q: What are the risk factors for gestational diabetes?

CC: In Canada, pregnant women are routinely screened for gestational diabetes. Women may be at increased risk for gestational diabetes if they are age 35 or older; are from a high-risk ethnic group such as African, Arab, East Asian, Hispanic, Indigenous or South Asian background; have a family history of diabetes; are obese, with a pre-pregnancy body mass index of 30 or greater; have previously had gestational diabetes; have a pre-existing condition such as pre-diabetes, polycystic ovarian syndrome or the skin condition acanthosis nigricans; use corticosteroid medications such as prednisone or celestone; or have previously given birth to a baby weighing more than nine pounds.

Q: Does gestational diabetes increase my risk for other pregnancy complications?

CC: Women who have gestational diabetes are at higher risk of having high blood pressure or preeclampsia. Also, with the risk of bigger babies comes a higher risk of Caesarean section delivery.

Q: How is gestational diabetes managed?

CC: Gestational diabetes is managed primarily through healthy eating, physical activity and regularly checking blood sugar levels (i.e., four times per day) with a blood glucose monitor. Medication (i.e., insulin) may also be necessary if blood sugars do not reach target levels with healthy eating and activity.

Q: How should I be eating if I have gestational diabetes?

CC: Women with gestational diabetes should follow healthy eating recommendations for pregnancy, while paying special attention to carbohydrates, which are the nutrient in food that raise blood sugar. All women diagnosed with gestational diabetes should meet with a registered dietitian for specific carbohydrate recommendations. Key nutrition suggestions include:

  1. Eat three meals and two to three snacks per day
  2. Choose high-fibre, low-glycemic-index carbohydrate foods more often. For example: berries, stone fruits and citrus fruits, whole grains, vegetables, milk and unsweetened yogurt.
  3. Limit foods and drinks that have a lot of added sugar such as jams, candies, chocolates and other sweets, soft drinks and juices.

Illustration by: Amy Wetton