MiraLAX (polyethylene glycol 3350) is generally considered low risk and is commonly used for short‑term treatment of constipation during pregnancy, but it should be used under the guidance of your prenatal provider. It is not known to increase the risk of birth defects or pregnancy loss when used as directed, because only a very small amount is absorbed into the bloodstream.
How it works and safety
- MiraLAX is an osmotic laxative that pulls water into the intestines to soften stool and improve bowel movements, and it does not stimulate uterine contractions.
- Professional groups such as gastrointestinal societies list polyethylene glycol–based laxatives as acceptable options if lifestyle measures (fluids, fiber, activity) are not enough during pregnancy.
When and how to use it
- It is typically recommended for occasional or short‑term use; long‑term, daily use in pregnancy should be discussed with your obstetric provider to ensure there is no underlying problem and to avoid issues like dehydration or electrolyte imbalance.
- Use the lowest effective dose and follow the package directions unless your clinician gives you a different plan.
Possible side effects
- Common side effects include bloating, gas, cramping, and loose stools or diarrhea, which can lead to dehydration if severe.
- If you notice severe abdominal pain, blood in the stool, no bowel movement despite use, or signs of dehydration (dizziness, very dry mouth, very dark urine), you should seek medical care promptly.
Alternatives and precautions
- Non‑medication strategies such as increasing fiber, drinking more water, and gentle physical activity are usually tried first in pregnancy.
- Other options your clinician may suggest include bulk‑forming fiber supplements or stool softeners like docusate, which are also commonly used in pregnancy.
Because every pregnancy and medical history is different, the safest approach is to confirm the dose and duration with your OB/GYN or midwife, especially if you need MiraLAX regularly or are in the first trimester.
