by Mira
(Australia)
QUESTION: My sister is 37 weeks pregnant and has been diagnosed with gestational diabetes. Our parents had type 2 diabetes, and she gained a lot of weight. How can gestational diabetes affect her and the baby?
Most women with gestational diabetes can have a healthy pregnancy and healthy baby when glucose is monitored and treated. At 37 weeks, good control still matters because high glucose can increase the chances of a large baby, difficult delivery, cesarean birth, preeclampsia, stillbirth, and newborn low glucose, jaundice, or breathing problems. Her obstetric and diabetes teams should review her readings, fetal growth, medicines, and delivery plan now.
Answer by Dr. Albana Greca, MD, MMedSc
Hi Mira,
Gestational diabetes develops when pregnancy-related insulin resistance raises glucose above the pregnancy range. Family history, age, previous gestational diabetes, and overweight can increase risk, but the diagnosis is not your sister's fault.
Gestational diabetes is usually diagnosed after the baby's major organs have formed, so it does not carry the same birth-defect risk as poorly controlled diabetes that was present around conception. However, some women diagnosed during pregnancy may have had previously unrecognized type 2 diabetes. Her clinician will interpret how early and how high the glucose was.
Even when diagnosed late, controlling glucose remains important for growth, delivery, and newborn health.
These are increased risks, not predictions. Many babies are born without complications, particularly when glucose and delivery are managed carefully.
Gestational diabetes increases the likelihood of high blood pressure, preeclampsia, induction of labor, cesarean birth, and gestational diabetes in a future pregnancy. It also identifies a substantially increased lifetime risk of prediabetes and type 2 diabetes.
Weight gain may contribute to insulin resistance, but it should not be used to blame her. Pregnancy weight goals and food intake should be reviewed by the maternity team rather than managed with crash dieting.
She should remain in close contact with her obstetric and diabetes teams. They may review:
Delivery timing is individualized. It depends on glucose control, whether medicine is required, fetal growth, blood pressure, testing results, and other obstetric factors. Gestational diabetes alone does not automatically require a cesarean birth.
Treatment may include an individualized meal plan, safe activity, and glucose testing. Insulin is commonly used when these measures do not keep glucose within pregnancy targets. Medicine decisions should be made by her maternity and diabetes clinicians; she should not start herbs, supplements, or a restrictive diet.
Common glucose goals are below 95 mg/dL fasting, below 140 mg/dL one hour after eating, or below 120 mg/dL two hours after eating, although her team may individualize them. Our guide to gestational diabetes treatment explains the main options.
The newborn team should know that the mother had gestational diabetes. The baby may need early feeding and glucose checks after birth. Staff will also watch for breathing difficulty, jaundice, temperature problems, or signs of low glucose.
Breastfeeding is encouraged when possible and may provide health benefits for both mother and baby. It should begin with support from the maternity team, especially if the newborn's glucose is low.
Gestational diabetes often improves after delivery, but it should not be assumed to have disappeared permanently. She should have a 75-gram oral glucose tolerance test 4–12 weeks postpartum. If that test is normal, she still needs diabetes screening every one to three years.
Healthy eating, activity, weight management after recovery, and breastfeeding when appropriate may help reduce future risk. See our guide to diabetes blood tests.
Contact the maternity unit immediately for reduced or absent fetal movement, vaginal bleeding, leaking fluid, regular painful contractions, severe headache, vision changes, pain under the right ribs, sudden swelling, chest pain, severe breathlessness, or very high glucose with vomiting or ketones. Do not wait for the next routine appointment when these symptoms occur.
At 37 weeks, the priority is not panic but close follow-up. Her clinicians should review glucose records and fetal growth and agree on a delivery and newborn-monitoring plan. Good glucose management during these final weeks can still reduce complications.
Educational safety note: This answer is for general diabetes and pregnancy education only. It does not replace personal obstetric or diabetes care. Do not start, stop, or change insulin, tablets, supplements, food intake, or activity without speaking with her maternity team.
Last reviewed: July 2026.
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