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I’ve run a total of 10 half marathons, 4 while pregnant!  Here’s an inside look into what it’s been like for me to continue running races while pregnant.  Pics included!

During my first pregnancy, I ran a half marathon when I was 16 weeks pregnant.  During my second pregnancy, I ran a half at 5 weeks pregnant.  Now, I’m 17 weeks pregnant with my third baby, and I ran half marathons at weeks 6 and 11.

That’s a whole heck of a lot of running with a baby in tow!

(And that doesn’t even take into account the pregnant running I’ve done during the second and third trimesters.)

Here’s a pic of me and my friend Heather after my very first half marathon while pregnant back in 2009.

running a half marathon while pregnant race photo 09

And here’s a pic of me with the same fabulous friend at my most recent half marathon while pregnant.

running a half marathon while pregnant race photo 13

(I have to say, Heather hasn’t changed a bit and I think I look even better now than I did 4 years ago.  Much less puffy.)

How does my training change while pregnant?

I ran a full marathon last fall, so I started training for this race with a very good base of fitness.

Here’s the training that I did during this pregnancy.

running a half marathon during the first trimester of pregnancy training

(The “Week” number refers to my training week, not to my pregnancy. I typically spend 12-16 weeks training for a half marathon.)

You can see that I stopped running Yasso 800’s after I found out that I was pregnant.  (You can learn more about Yasso 800’s and how I train to run faster in a previous blog post.)  My main goal was to maintain distance so I would be comfortable running 13.1 miles on race day.

I even ended up running a half marathon while training (at the end of training week 7).

In general, I just listened to my body, stayed hydrated, and ran at a comfortable pace.

I ran a similar number of miles per week to what I run non-pregnant.

What have I learned from running a half marathon while pregnant?

Start with a strong running base.  I hope I’m not the first person to tell you that pregnancy is a steady DECLINE of fitness.  It’s just what happens.  It’s normal.  The fact that I’m going to get less and less fit motivates me to start each pregnancy at a high level of fitness with lots of room to go downhill.  Pregnancy isn’t the time to try to increase running speed or distance.  When I’m pregnant, I just run for fun.

Focus on the big picture.  A healthy, fit pregnancy and a beautiful healthy baby are much more important to me than any race.  As my running decreases during pregnancy, I try to focus on the GREAT things that I’m doing for myself and my baby and how much easier it will be for me to get back in shape post-baby.

Listen to your body.  When I feel great, I run, but I have no problem slowing down or walking if I need to (especially up Pittsburgh’s moster hills).  Pregnancy is the only time that I cut myself a break fitness-wise, so I try to take advantage of it.

Stay hydrated.  I try to drink water every mile while running.  During a half marathon, I also drink sports drinks.

Run with a friend.  Three of the four times that I’ve run a half marathon while pregnant I’ve run the race with someone else.  Since I’m just running for fun, it’s nice to have someone to talk to over the 2-hour run.  It also helps keep me from feeling discouraged and disappointed that I’m not giving the race 100% and running as fast as I can.    

How do I stay motivated?

I’m not a “supermom” or super athlete.     

There were plenty of days in the first trimester of this pregnancy when I was dog-tired and didn’t feel like running.  Almost all of my training runs took place in the afternoon on my treadmill when my younger daughter was napping.  This also happened to be the time of day when I was most exhausted.

I ran anyway.

Believe it or not, having a half marathon on my calendar reminded me how important it was to keep running.

Since this is my third pregnancy I know how important staying active is.  Because I was active during my previous two pregnancies, I was able to:

  • Keep my weight gain within the range recommended by my midwives (20-30lbs)
  • Lose my baby weight quickly and easily after birth
  • Stay happy and healthy through two uncomplicated pregnancies
  • Take care of my first little one while super preggo with #2
  • Get back in super shape post-baby (twice!)

Now that I’m already a mom, showing my girls that exercise is a “normal” part of life is the icing on the cake.

Here’s a pic of my daughter Isla holding a sign that my parents made for my half marathon while pregnant before Easter this year.

running a half marathon during the first trimester of pregnancy - isla

If that’s not motivation to keep running, I don’t know what is.

More info and support

Looking for more support for staying active during prenancy?  Follow my fit pregnancy journey on Facebook ( and Instagram (@kellymcnelis).  

You can also read my best tips for getting back in shape after having a baby and the three running workouts that I use to get back in shape and run faster after giving birth.

Have you participated in a race while pregnant?  Leave a comment below.  I’d love to hear about it!!


PS I don’t claim to be a personal trainer, running coach, midwife, or OB-GYN. While I’m happy to share my experiences as inspiration, please read my disclaimer and consult some of those experts before trying anything yourself.  The most important thing during pregnancy is to keep you and your baby healthy.

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11 years ago

That is VERY awesome of you to do! Go Girl!

11 years ago

Thanks, Trista!

10 years ago

Thanks for sharing your story. I will be 12 weeks pregnant when running a half-marathon next month, and it’s nice to hear from people who don’t poopoo that. A good friend just this morning told me have me all sorts of scary warnings and told me to dial it back (I am only 4 weeks pregnant) and take it easy. My plan is to exercise moderately, stay cool, and hydrate often.

10 years ago

Awesome job Kelly! You are an inspiration!
I am currently 20 weeks pregnant with our 2nd child (we have an almost 3 yo girl).
I ran my 2nd Half Marathon when I was 12 weeks pregnant.
My Mom ran it with me, which was an awesome experience!
We just walked while drinking water at the water stations.
Although I ran it 20 min slower than my first Half (while not-preggo), & the recovery was tougher with this one, it was a fun and rewarding experience!
Thank you for sharing your insights on running while pregnant!

10 years ago

I’m training for my first half marathon and I’m 5 weeks. I keep reading your blog to keep me going. I’m just a little nervous since my first baby came at 6 months and your body tends to remember childbirthing . Meaning, should I stop and be cautious since my last baby was so premeature? Should I just listen to my body and not push it? Or should I just do what you ladies are doing?

Lauren @ Lettuce Eat Cake

Thanks so much for your thoughts! I’m registered for my first half in 9 weeks, and currently trying to get pregnant. If I do get pregnant this month, I’d be about 10 weeks along by race day. I’ve never been pregnant before and have no idea how I will feel, and I haven’t asked my doctor about it, so I guess it’s just a “cross that bridge when I get to it” kind of situation. I am not an extremely serious runner. Currently run around twice a week, usually a max of 10 miles a week. Any advice to share?… Read more »