by Jackie Page
(Canada)
QUESTION: My daughter is 31 weeks pregnant and has gestational diabetes with high glucose levels. She is using insulin under specialist guidance, but the baby's movements have decreased noticeably for three days. A heart-rate check was reassuring, but no ultrasound was performed. Could the insulin be harming the baby, and why is the baby moving less?
Insulin injections do not harm the baby and are commonly used to treat gestational diabetes. However, a clear reduction in fetal movement at 31 weeks—especially for three days—requires immediate reassessment by the maternity unit, even if an earlier heart-rate check was normal. She should contact maternity triage or labor and delivery now and should not wait for movement to improve at home.
Answer by Dr. Albana Greca, MD, MMedSc
Hi Jackie,
The concern here is the change in the baby's usual movement pattern, not the insulin. Insulin is used because uncontrolled glucose poses risks to both mother and baby. Human insulin preparations used during pregnancy have not been shown to cross the placenta.
Babies have normal sleep periods, but they should continue to move regularly through the third trimester. The type of movement may change as space becomes tighter, but movements should not simply become much less frequent because the baby is “lazy.”
A noticeable reduction or change from this baby's normal pattern can sometimes be a sign that the baby needs assessment. A reassuring heartbeat at one moment does not guarantee that everything remains well, and a home Doppler cannot confirm fetal well-being.
Because she is over 28 weeks, the maternity team may repeat a full assessment, monitor the baby's heart rate continuously with a nonstress test or CTG, check blood pressure and glucose, and decide whether an ultrasound is needed to assess growth, amniotic fluid, movement, and placental blood flow.
There is no single number of daily movements that is normal for every pregnancy. What matters most is a reduction or change from the baby's established pattern. Advice such as waiting for fewer than ten movements in a whole day may delay necessary care.
She should not spend additional hours trying cold water, a sugary drink, changing position, or repeatedly pressing on the abdomen before seeking help. If movements remain reduced after a reassuring assessment, she should contact the maternity unit again.
Insulin is generally the preferred medicine when food and activity are not enough to control gestational diabetes. It does not make the baby inactive and does not cause birth defects. The purpose of treatment is to reduce the effects of maternal hyperglycemia.
Insulin can cause low glucose in the mother if the dose is too high, food is delayed, or activity changes. Maternal hypoglycemia should be treated promptly according to her pregnancy plan, but it should not be assumed to explain a persistent three-day reduction in fetal movement.
She should continue insulin exactly as prescribed unless the maternity or diabetes team changes the dose. Stopping insulin may allow glucose to rise and increase pregnancy risks.
Persistent high maternal glucose can contribute to excessive fetal growth, increased amniotic fluid, difficult delivery, newborn hypoglycemia, jaundice, breathing problems, preeclampsia, and stillbirth. These are increased risks, not inevitable outcomes, and better glucose control reduces risk.
Common pregnancy 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. Her own team may individualize these targets.
She can use a blood sugar log and review our guide to gestational diabetes treatment.
If monitoring is reassuring, the maternity team may send her home with instructions about her baby's usual movement pattern and when to return. Because she has insulin-treated gestational diabetes, fetal growth and well-being may require additional surveillance depending on glucose control and other pregnancy findings.
Any further reduction or another episode of changed movement should be reported again. She should never worry about “bothering” the maternity unit.
Contact maternity triage immediately if fetal movement is reduced, changed, or absent. Seek emergency help for no movement with severe abdominal pain, heavy bleeding, fainting, seizure, chest pain, severe breathlessness, or collapse. Also contact the maternity team urgently for leaking fluid, regular painful contractions, severe headache, vision changes, pain under the right ribs, or high glucose with vomiting or ketones.
The insulin is protecting the pregnancy by treating high glucose; it is not making the baby “lazy.” A three-day decrease in movement at 31 weeks warrants immediate repeat maternity assessment. A normal earlier heart-rate check is reassuring but does not replace reassessment when the movement change persists.
Educational safety note: This answer is for general diabetes and pregnancy education only. It does not replace urgent obstetric assessment. Do not stop or change insulin, food intake, or activity without instructions from the maternity and diabetes teams.
Last reviewed: July 2026.
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