When Does Constipation Start in Pregnancy?

Published May 31st, 2022 by Bridget Reed
Fact Checked by
Camille Freking
Medically Reviewed:
Dr. Angel Rivera

Although it’s uncomfortable, constipation is a very common symptom that women experience during pregnancy, even in the first trimester.

Some women may begin to suffer from constipation as early as the first month, while others may not feel it until the fetus is almost fully developed.

Regardless, nobody wants to feel constipation — in addition to all the other physical changes that come with being pregnant.

The good news is that it’s more than possible to prevent constipation during pregnancy. This guide from USA Rx breaks down how to do just that. 

What Causes Constipation During Pregnancy?

Constipation means that your body is having trouble producing a bowel movement.

During pregnancy, the causes of constipation can include:  

  • Rising progesterone levels: Progesterone is a hormone that’s naturally made by the ovaries. It helps your body thicken the uterus (making it ready to carry a fetus), which means that your progesterone levels will naturally rise during pregnancy. While this is generally a good thing, changing hormone levels can decrease how quickly your body digests food, resulting in constipation. 
  • Prenatal supplements: Many prenatal supplements contain high amounts of iron. This nutrient helps your body make more blood, which will supply oxygen to the fetus. However, supplementing with iron can cause extreme constipation in addition to other digestive symptoms, like nausea and vomiting. 
  • Lifestyle: As a result of decreasing energy levels and increasing food cravings, being pregnant can cause you to make some lifestyle changes. This may lead you to nix your old healthy habits that might include ample exercise and healthy eating, in exchange for becoming more sedentary or eating more junk food, which can lead to an increase in constipation. 
  • Your growing baby: As your baby grows and develops inside your uterus, it may put extra pressure on your gastrointestinal (GI) tract and your rectum. This pressure can make it harder for digested food to make its way out of the body, leading to an increase in constipation. 

When Does Constipation Start in Pregnancy? 

When pregnancy constipation starts depends on each expecting mother’s unique digestive system health.

Some mothers may begin to experience constipation when they start supplementing with iron.

While many women wait until they are pregnant to take prenatal vitamins, others may choose to get a head start with their prenatal wellness routine (usually under the supervision of their women’s health provider).

Depending on how their bodies react to the extra iron, they can become constipated before getting pregnant or in the early days of their pregnancy. 

For some expecting mothers, constipation may begin shortly after a missed period, as progesterone hormone levels rise.

The levels of this pregnancy hormone generally begin to go up shortly after conception.

However, the constipation caused by progesterone will be felt most around two to three months into the pregnancy

Some mothers may go through their first and second trimesters of pregnancy without experiencing constipation at all.

However, when the fetus gets large and begins to press down on the GI tract, constipation may arise as a result. This usually happens around the third trimester.

How Can You Prevent Constipation Pregnancy? 

While there isn’t much you can do to prevent hormonal changes during pregnancy, there are a few ways you can improve the function of your digestive tract and reduce the constipation, bloating, and even heartburn that can come with pregnancy. 

when does constipation start in pregnancy

Here are five tried-and-true strategies for preventing constipation: 

  1. Get enough fiber: This is the simplest strategy to reduce constipation, and it can benefit your health in many other ways — it might even help prevent straining that could lead to hemorrhoids. General guidelines recommend 30 grams of fiber — to get there, use a nutrient tracker until you get an intuitive sense of what (and how much) you need to eat to get enough daily fiber. If you include lots of veggies, fruits, legumes, and whole grains like cereals and bread at every meal, then you should meet your goal fairly easily. Of course, you can always speak to your doctor about taking a daily fiber supplement, such as Metamucil.
  2. Drink enough water: When you’re pregnant, your fluid intake needs to go up. Not only does this help support a healthy pregnancy, but it can also help you battle constipation. Fluids, including fruit juice (especially prune juice), can serve as stool softeners. 
  3. Get plenty of exercise: Pregnancy can cause you to feel seriously fatigued, which can make it hard to get active. However, physical activity has tons of health benefits during pregnancy, which include relief from constipation. Try to get 30 minutes of moderate-intensity exercise about three times per week. A strong pelvic floor could help make for smoother labor, too, so do your Kegel exercises to potentially help your bowel movements now and your delivery later. 
  4. Supplement with probiotics: Probiotics are microscopic bacteria that help to support gut health. You can get probiotics from fermented foods, such as yogurt, sauerkraut, and kimchi. Or you can get a high-quality probiotic supplement. Studies show that probiotics are one of the most effective ways to relieve constipation. 
  5. Switch up your prenatal vitamin: During pregnancy, doctors recommend upping your iron intake, increasing it each month as the baby gets bigger. However, some prenatal vitamins contain too-high amounts of iron, increasing your chances of becoming constipated. Talk to your doctor about switching to a different prenatal vitamin that works better with your gut chemistry and is conducive to easier bowel movements. 

In Conclusion 

As your pregnancy progresses, your body goes through many changes, which can increase your chances of becoming constipated. 

You may begin to feel constipated as soon as you begin supplementing with prenatal vitamins, which contain a high amount of iron.

On the other hand, it might take your body a few months before you experience constipation, often beginning when the hormone progesterone rises in the second or third month of pregnancy. 

If you’re lucky, constipation may not be a problem until well into your pregnancy, when your baby gets big enough to physically press down on your digestive tract. 

While you can’t keep your body from changing during pregnancy, there’s plenty you can do to decrease pregnancy symptoms like constipation until you reach your due date.

Upping your fiber, water, and probiotic intake, getting plenty of exercise, and reducing your iron supplementation are all ways to help reduce constipation.

Just make sure to talk to your healthcare provider before making any changes. This will help make sure that you and your baby are as healthy as possible all throughout your pregnancy. 

If you experience additional symptoms like intense abdominal pain, cramping, and/or alternate constipation with diarrhea, talk to your doctor immediately, as this may indicate a more serious problem.

References and Sources: 

Ferrous Sulfate Supplementation Causes Significant Gastrointestinal Side-Effects in Adults: A Systematic Review and Meta-Analysis | NCBI 

Benefits of Exercise in Pregnant Women | Dominican Scholar  

Effect of Probiotics on Functional Constipation In Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials | The American Journal Of Clinical Nutrition

Iron Supplementation during Pregnancy and Infancy: Uncertainties and Implications for Research and Policy | PMC 

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