Anatomy of a Pregnant Runner

It’s an understatement to say pregnancy changes your body. The hormones, the baby, and the physical accommodations your body makes for the baby might affect your runner body in strange ways. Generally speaking, we expect to be more tired than usual and for our paces to slow down. But almost every part of your runner body from your head to your toes changes throughout your pregnancy!

What to expect from running when you're expecting



Dizziness during pregnancy can be caused by a number of things. If experienced on the run, back off and sit down if you need to. It’s also a concern if you are doing yoga, pilates or other strength training where you may lie flat on your back. In this position, your uterus and the baby can place pressure on a large vein in your back called the vena cava, reducing blood flow.

Pro-Tip: Avoid doing any exercise that requires you to lay flat on your back, make sure to stay hydrated before, during and after your runs. It’s good to have a snack before you run as well, this helps prevent drops in blood sugar which can cause you to become dizzy or lightheaded.

When to Call the Doctor: If the dizziness is accompanied by a headache, rapid heart rate or palpitations, or blurred vision, stop and get medical attention immediately.


With a growing belly and changing body, your center of gravity is different than it used to be. It’s certainly something you need to be more careful about as falling can put you and your baby at risk.

Pro-Tip: Avoid more technical terrain such as trails and poorly maintained roads. Avoid wet, slippery and snowy road conditions. Bad weather days offer a great opportunity to cross train or take to the treadmill.

Nose and Sinuses

Pregnancy Rhinitis: You may notice that you’re sneezing more, feeling stuffed up and getting more sinus headaches. The increase in mucous production, extra estrogen and increased blood flow are the culprits. Sometimes running can help loosen things up and actually HELP, but other times it might be best to take a rest.

Pro-Tip: Sleep with your head a bit elevated which will help things drain better, and make your days a little less pressured and snot filled, therefore making running easier too! If you’re battling a bad sinus headache or the usual tricks are not working to help congestion (Neti pot, saline, etc.) it might be better to take a few days off of running until you can breathe easier (and enjoy the run more without head pounding!).

When To Call The Doctor: If your symptoms are worsening or last an extended period of time it’s best to call your doctor. Do not take any OTC medications without first discussing it with them as well. I ended up with a very bad sinus infection which required 10 days of antibiotics during my second trimester. You worry about taking something, but at the same time you don’t want infection to spread or worsen.


The good news is that doctors no longer suggest their pregnant patients limit their heart rate while running. Still, you may find it’s far easier than normal to get your heart rate up which usually means your paces are going to slow way down over the course of the nine months. This effect may also leave you feeling fatigued or needing to take breaks more often than usual.

Pro-Tip: While pushing the pace or even racing might still be fun, if it’s not, no need to push it if you don’t want to. Avoid extreme heat conditions, and make sure to stay well hydrated. If in doubt, slow it down.

When to Call the Doctor: If you notice drastic changes in heart rate like a rapid heart rate that won’t slow down even upon resting or have chest pain or palpitations that worry you, seek medical attention immediately. If it does not seem to be an emergency, but you notice a funny heart beat from time to time, consult your obstetrician or midwife.


Even before you realize you’re pregnant, you may feel more breathless while running. This you can blame on hormones that swell the capillaries in your lungs and relax your breathing muscles, which might make you feel like your sucking wind even at an easy pace. Later, with a growing baby, your uterus starts to push up on your diaphragm which results in less oxygen with each breath.

Pro-Tip: If you feel like you can’t get in enough air, slow down! Walk if necessary.

When to Call the Doctor: Worsening asthma, heart palpitations, chest pain, persistent cough, or cough combined with fever or chills, contact your doctor’s office or seek immediate medical attention as warranted. Pregnancy increases your chances of respiratory illness complications so get your flu shot!

What to expect from running when you're expecting

Digestive System

The obvious issue here is nausea and vomiting, particularly in the first trimester. The good news is, an easy run might relieve your symptoms, at least for a little while.

As your pregnancy bumps along, as true for any runner, you’ll learn what foods work before runs and which ones don’t. This can drastically change from non-pregnant running to pregnant running with the addition of food aversions, constipation, and heart burn.

Pro-Tip: Common heart burn culprits are acidic or fatty foods. You can often avoid constipation by eating enough fiber and drinking enough fluids, but during the first trimester, even that might not work.

When to Call the DoctorIf nausea, vomiting, heartburn or constipation are severe talk to your doctor.

Lower Back

As you gain weight your body has to support that weight. A lot of that pressure falls on your spine. Add in your expanding uterus and a growing baby that put pressure on nerves and blood vessels, back pain is almost inevitable.

Pro-Tip: Try a maternity support belt which can relieve some of the strain on your lower back. Stretching regularly, or even taking up yoga can be a great way to strengthen and support your growing body. Some poses and stretches may be off limits for mamas-to-be so it might be a good time to find a prenatal yoga class, or hit up Amazon for some prenatal yoga DVD’s that you can do at home.


Round ligament pain can be the bane of many pregnant runners’ existence. It can feel like a little cramp or a stabbing pain under your belly and running can exacerbate it.

Pro-TipThat maternity support belt can also help you here. Sometimes taking a walk break is enough to make the pain go away or you might try doing regular walk breaks through a run to give the ligaments a regular break from the bouncing.

Belly Button

If your belly button pops out, it’s volunteering to get chafed.

Pro-tip: If a little anti-chaffing ointment isn’t doing the trick, take a tip from the dudes, and cover up the belly button with a band-aid or nip guards.


Two words: Braxton Hicks. As you get further along in pregnancy, these uterine contractions may become more frequent. Sometimes activity can even bring them on, other times activity can help ease the discomfort.

Pro-Tip: If you’re running when you have a contraction, stop and drink some water and rest before resuming activity. Dehydration can cause BH contractions, so yet another reason to focus on drinking more water before, during and after activity.

When to Call the Doctor: It’s good to read up on the differences between BH contractions, and actual labor, but when in doubt call your doctor. If you’re worried, this is one of those times when it’s better to be safe than sorry. If the contractions become more regular, or you experience extreme abdominal pain combined with low back pain, stop and call you doctor immediately.


Between all that extra fluid flowing through your body, and the pressure on your bladder, it’s only natural that you’re going to need to pee … a lot!

Pro-Tip: Plan short loops around your house or a park with a bathroom, or opt for the treadmill where the potty is easy access. Remember, DON’T restrict drinking water to limit bathroom stops, you and your baby need that water!


The pregnancy hormone relaxin loosens the ligaments that hold the pelvic bones together. This can cause instability and pain in the pelvic bone, but sometimes also pain that travels down the legs. This is commonly referred to as symphysis pubic dysfunction (SPD).

Pro-Tip: As someone currently dealing with this, the best advice I can give is to include a warm-up before exercise. Whether it be a short walk, jog, or drills before diving into running, a warm-up can make a big difference. Doing exercises such as kegels and pelvic tilts can help strengthen the area as well.

When to Call the Doctor: Before taking medication for the pain, consult with your doctor. Tell your doctor about this pain at your next appointment. You will want to keep an eye on this, as the pelvic bones can separate causing diastasis symphysis pubis (essentially, dislocation).

What to expect from running when you're expecting


As runners we’re used to leg cramps, but they can definitely become more common during the second and third trimesters. While more often they happen at night, or after extended periods of standing or sitting, it can still happen during your runs as well.

Pro-Tip: Wear compression gear, avoid sitting or standing for extended periods of time, and make sure you are properly hydrated. When the cramps come on, it’s best to stop and stretch, calf stretch especially, before resuming your run.

When to Call the Doctor: If you have severe leg pain with swelling and a fever, it’s best to contact your doctor as soon as possible.

Feet and Ankles

Later in pregnancy, both feet and ankle swelling becomes noticeable for many women due to increased fluid and blood in your system. Your running shoes may not fit the same, and seams on your clothing, specifically around your extremities, might be a bit more snug and uncomfortable.

Tip: Compression gear can help reduce swilling, as well as elevating your feet when you’re lying down before or after a run. Avoid excess salt intake, and ensure you are drinking enough water; this seems counter-intuitive to reduce swelling, but flushing your system really does help!). Make sure you are wearing proper fitting shoes and clothes and go up a half or full size if you need to.

When to Call the Doctor: If you experience any sudden swelling, it’s best to call your doctor right away. Additionally any swelling that appears with pain, and potentially a fever, is important to get checked out.


Pregnancy causes many women’s nails to grow more quickly, so you may need to trim your toenails more frequently than normal.


All of the added weight your body is supporting adds extra stress. Besides your spine, this puts strain on joints like your hips and knees.

Pro-Tip: You might need to invest in some more supportive shoes for the time being, and opt for softer surfaces for your runs such as the track or treadmill. It’s also worth noting that some of the supplements for joints that you might take during training, such as glucosamine, are generally not found to be proven safe during pregnancy.


Hormones increase your sensitivity to the sun making you more likely to burn, even if you’re only outside for a little while.

Pro-Tip: Wear a hat, don’t run at peak sun times, and wear sunscreen (avoid sunscreens with oxybenzone, use those that contain zinc oxide and titanium dioxide instead).

Chloasma (Mask of Pregnancy)

You might notice that you start developing dark or hyper-pigmented patches on your face during pregnancy, and while this doesn’t impact your running, your running can actually impact the severity of it. During pregnancy the chances of this are increased but there are still some things you can do to help.

Pro-Tip: According to the American Pregnancy Orgnaization, it’s not recommended to use retinoids during pregnancy, however using a topical Vitamin C is considered safe and effective during pregnancy.


The changes that happen to your body while growing your little one can have both expected and unexpected effects on your running. Some might leave you fuming while others you’ll just have to laugh about… like any increased flatulence you may experience on the run! The one certainty in pregnancy? It will end!

How did pregnancy affect your running?

A new mom and Upstate, NY resident who loves the marathon, a good beer, and all of the numbers/nerdy things. I write about my journey to a sub-3:00 marathon, training tweaks for improvement, and finding that "running/life balance" unicorn. On tap Next: Maneuvering through motherhood and postpartum running!

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  1. Okay, so a note on the dizziness. As someone with ridiculously low blood pressure, I had to be sure to eat a lot of salt/potassium, not just stay hydrated. That seems obvious, but I didn’t put it together until I almost smooshed an 85-lb friend of mine. She saw me weaving and said “I can’t catch you, better sit down!” So obviously not to consider if you have high blood pressure, but a heads up that water may not be enough….

    1. That’s a great point Colleen! BP typically drops more in 1st and 2nd tri so for someone like you (and me too) with naturally low BP this can be an issue to watch and you’re 100% right…water won’t be enough. As I enter third trimester this week (about the time BP slowly starts to go back up) I’ll be curious to see what my BP is.

      I also am a person who doesn’t really like drinking plain water, I’ve never been good about it. I drink Nuun a lot simply because it gives it enough taste to make me more likely to drink- but also helps with my sodium and potassium which tend to be lower. I continued that through pregnancy so far and seemed to help!

      1. I found out I was pregnant on week 2 of training for my first 5K (which I ended up walking) back in 2009. Pregnancy stopped me in my tracks. I felt like my knees and hips were “loosey goosey” from the hormones. With that plus the change in center of gravity, just walking was a challenge. I was also nauseous… all day, every day for 5 and a half months.

        I also have naturally low BP. Plain water can be yucky sometimes; I feel like during pregnancy my palate was a lot less forgiving of things like old ice or even a hint of chlorine in the city water. Nuun is great if you are also trying to keep your electrolytes balanced! If you just want some flavoring, then you could also try True Lemon (it’s crystallized lemon in little packets, they also make grapefruit, orange, and lime). It’s just fruit and citric acid, no sweeteners or sugar.

        (p.s. It took a long while after pregnancy, but I DID finally run a 5K…and another… and another… and then a 10K… and now I’m training to be part of a marathon relay team. :])

  2. I love this! It is so true, and so important to know all of these things listed can really affect you during your pregnancy. It’s crazy how quickly things change, and how much you have to adjust to those changes. I learned really quickly about the breathlessness, fatigue, and body changes 🙂 I definitely feel my legs swelling at work much sooner than normal (despite compression socks) and lately I drink water like a fish. I noticed too almost immediately my resting heart rate increased… my fit bit keeps track of it for me and I’m usually mid 40’s, but now I’m well above 60. Even week 5-6 I was up to the 50’s! I love it though. How amazing is the human body? <3