Can I Take MiraLAX While Breastfeeding?

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After bringing your little one home from the hospital, you want to be the best parent you can possibly be. For some people, that means breastfeeding. And while breastfeeding can be difficult in its own right, dealing with the aches and pains that come with the postpartum period, such as constipation, can really knock you out.

While you may have strategies that worked in the past to fight constipation, when you're spending so much energy breastfeeding it's fair to look for a quick fix. And the over-the-counter (OTC) laxative MiraLAX (polyethylene glycol 3350) can be that easy solution.

"Constipation is very common in the week or two after delivery," says Nathan Fox, MD, OBGYN, a maternal-fetal medicine specialist and host of the Healthful Woman podcast. "MiraLAX is a safe option to take while breastfeeding." Here is what you need to know about how MiraLAX works and how to take it safely.

What Is MiraLAX?

MiraLAX is what's called an osmotic laxative, which is one of the most common laxatives you'll find at the drugstore. "It works by drawing water into the colon, which softens the stool and makes it easier to pass it," says Sarah McBane, PharmD, associate dean of pharmacy education at UC Irvine School of Pharmacy and Pharmaceutical Sciences. "If you've heard of stool softeners, that's another term for an osmotic laxative."

This is different from a stimulant laxative, which induces a bowel movement by increasing the contractions of the intestinal muscles.

MiraLAX comes in liquid form or powder form. In both cases, you would mix the directed amount of medication into a hot or cold sip and drink it. You typically need to take MiraLAX for a couple of days (usually one to three) before you will have a bowel movement.

Is It Safe to Take MiraLAX While Breastfeeding?

It is safe for breastfeeding parents to take MiraLAX. "The active ingredient is minimally absorbed by the body, so very little of the medication will be passed onto a nursing infant," explains Dr. McBane. That means you can get the benefits of an easier bowel movement without worrying about your baby.

Even though MiraLAX can be effective, Dr. Fox recommends trying some natural methods first to get things moving. "I usually recommend dietary modifications first, such as increasing water intake as well as high-fiber foods like fruits, vegetables, or a cereal with bran," he says. "These tend to be gentler and less likely to cause side effects than MiraLAX or other laxatives."

Drinking more water can actually be doubly beneficial, as staying hydrated can keep your milk production where it needs to be to nourish your baby.

Every breastfeeding journey is different. Be sure to consult with a healthcare provider about your circumstances if you have any questions about taking MiraLAX while breastfeeding.

Safety Precautions

MiraLAX is generally considered to be a safe and well-tolerated medication for constipation, but there are a few possible side effects that breastfeeding individuals should be aware of. Namely, the medication can cause gas, bloating, nausea, and diarrhea.

It can also cause abdominal cramping, which is incredibly common postpartum because the uterus is contracting and shrinking back to its normal size. These pains are usually stronger when you're breastfeeding, thanks to the way that nursing stimulates the release of oxytocin, a hormone that triggers the uterus to contract. If you're already experiencing uncomfortable cramps, you may not want to risk additional ones from taking MiraLAX.

Some people are allergic to polyethylene glycol, the active ingredient in MiraLAX. Although these allergies are rare, reactions can be severe.

Breastfeeding Safe Alternatives

Even though MiraLAX is a safe, OTC laxative to use for occasional constipation while you're breastfeeding, experts recommend trying some natural remedies first to help get things moving. If these strategies don't work within a few days, MiraLAX is a great option.

Soluble Fiber-Rich Foods

Foods that contain soluble fiber absorb water as they move through the digestive tract, forming a paste that helps food and waste pass through. Plus, since soluble fiber is not broken down and absorbed during digestion, it is safe to consume during breastfeeding. Top sources of soluble fiber include psyllium husk, beans, oats, and Brussels sprouts.

Water

Dr. Fox recommends upping your water intake to fight constipation before trying anything else. Drinking more water will help soften your stool and stimulate more frequent bowel movements.

To get things moving fast, drink more water along with upping the fiber in your diet. In one study, patients with chronic constipation who drank two liters of water daily in addition to a high-fiber diet saw greater increases in stool frequency and a decrease in laxative use than those who didn't sip as much H2O.

Exercise

Regular exercise keeps the muscles that are responsible for moving food through the digestive tract strong, helping to prevent constipation.

Light to moderate exercise (such as walking, Pilates, or yoga) is best to keep up milk supply and prevent breast infections while breastfeeding. Intense, strenuous exercise (such as cycling or high-intensity interval training) can cause lactic acid to build up in the muscles, small amounts of which can enter your breast milk and alter the taste, which may bother some babies.

To eliminate any chance that your baby will refuse to feed, breastfeed or express your breast milk right before you exercise or wait at least 90 minutes after an intense workout before nursing to give the lactic acid levels time to decrease. Sweat may also make your breast taste salty, which your baby may not like, so taking a shower or washing the area before breastfeeding is also smart.

A Word From Verywell

If you experience constipation while breastfeeding, MiraLAX can be a safe and simple quick fix, though experts recommend using more natural remedies first if you are suffering from chronic constipation. Regardless, it's important to speak to your healthcare provider for more personalized recommendations on the best treatment for you.

8 Sources
Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Drugs and Lactation Database (LactMed). Polyethylene Glycol.

  2. National Library of Medicine. Polyethylene Glycol 3350.

  3. Gordon M, MacDonald JK, Parker CE, Akobeng AK, Thomas AG. Osmotic and stimulant laxatives for the management of childhood constipationCochrane Database Syst Rev. 2016;2016(8):CD009118.

  4. Science Direct. Uterine Contraction.

  5. Sellaturay P, Nasser S, Ewan P. Polyethylene glycol–induced systemic allergicreactions(Anaphylaxis). The Journal of Allergy and Clinical Immunology: In Practice. 2021;9(2):670-675.

  6. Drugs and Lactation Database (LactMed). National Library of Medicine (US). Psyllium. Updated May 17, 2021.

  7. Anti M, Pignataro G, Armuzzi A, et al. Water supplementation enhances the effect of high-fiber diet on stool frequency and laxative consumption in adult patients with functional constipation. Hepatogastroenterology. 1998;45(21):727-732.

  8. Lee S, Kelleher SL. Biological underpinnings of breastfeeding challenges: the role of genetics, diet, and environment on lactation physiologyAm J Physiol Endocrinol Metab. 2016;311(2):E405–E422. doi:10.1152/ajpendo.00495.2015