Week 12


Week 14


Your Baby at 13 Weeks Pregnant

Baby’s growth and size

Baby is about 3 inches, up almost a whole inch from last week! And is getting a whole lot closer to that 1-ounce mark, weighing in somewhere between 0.8–0.9 ounces. 

While it might not seem like a lot, just remember where you started – 0.04 inches at week 4!

What’s new developmentally? 

Baby’s skin is still thin and transparent at the moment, but it won’t be for long. And new this week, lanugo is starting to form!

Lanugo is a type of soft, fine hair that can be found on baby’s skin while in utero. Lanugo helps protect baby and keep them warm while they are growing in your belly. For some babies, lanugo is still present at birth, especially if baby is a bit on the premature side!

Fun facts about your week 13 baby

  • Baby is beginning to make urine 
  • Ovaries or testies are fully developed internally; external genitalia are still forming 
  • Baby’s eyelids remain fused shut to help protect their eyes


Week 13 of Pregnancy 

Week 13 pregnancy symptoms 

Some of those pesky early pregnancy symptoms might still be lingering but hopefully you are one step closer to feeling like yourself this week!  

How should I be feeling at 13 weeks pregnant?

Congratulations, you made it to the final week of your first trimester! This is truly a cause for celebration, mama!!

There is a good chance that the morning sickness and fatigue are both beginning to subside, if they haven’t already. And while you might be fortunate enough to say goodbye to some symptoms, you might be saying hello to some new ones this week or next. 

Don’t worry though, a lot of women refer to the second trimester as the “honeymoon” trimeter so things should be looking up for you! And speaking of looking up, you might even notice an increase in your sex drive around this time, which might have you wondering if it’s safe to have sex during pregnancy. 

If you are looking for the answer to this question and other sex during pregnancy questions, look no further than right here!


More Week 13 Info

13 weeks pregnant ultrasound

There are a few reasons why you might be receiving an ultrasound at 13 weeks pregnant. You should have had an initial ultrasound to confirm your pregnancy and verify your dating by this point, but if you haven’t then that might be done now. 

The nuchal translucency screening (NT scan), which tests for chromosomal anomalies like Down syndrome, is typically performed between 11 and 14 weeks. And you are still inside that window! 

The NT scan is time sensitive – it’s important to complete it prior to 14 weeks for accuracy. This test is a screening tool only and would require additional testing to confirm a positive result. 

To learn more about genetic screening tests, high risk pregnancies, and more, take a listen to my podcast interview with OBGYN, Dr. Marta Perez!

13 weeks is how many months?

You are going to hear pregnancy discussed in weeks the majority of time. But if you are wondering about how many months you are at 13 weeks, the answer is three. 

This can be a bit confusing, as you will be in your third month for a few weeks, but at 13 weeks pregnant you are in the final week of your third month!

13 weeks pregnant belly still soft

A lot of things impact when you start showing in pregnancy and why all baby bumps look different. If you find that your belly looks more like you just consumed Thanksgiving dinner and less like a baby bump at 13 weeks, do not fret, you certainly are not alone. 

A soft pregnant belly at 13 weeks is not a cause for concern and is likely related to genetics and your body shape/size more than anything else. Learn more about your pregnant belly and when you start showing in this article on the blog!

13 weeks pregnant with twins

Do you have more than one baby growing in there? You are in the right place to learn more about being 13 weeks pregnant with twins! To be entirely honest, there’s not a huge difference just yet. Your babies might be a tad smaller than a singleton but are likely very similar in weight and length, about 0.8 ounces and 3 inches. 

Developmentally, your babies are doing all the same things as a singleton. You can expect them to be almost fully developed in terms of internal organs, facial features, hair, and teeth. Your babies also have fingerprints!

How is mama feeling? With twins, it’s not uncommon for those first trimester symptoms to linger a little bit longer. For the most part though, you will be feeling the same things that were previously mentioned. 

It might be smart to go ahead and invest in a good pregnancy pillow. With two babies in there, your sleep might start getting interrupted a bit earlier. There are so many different shapes and sizes of maternity pillows. If you need help narrowing it down to one, you can check out the ones I have on my Amazon Storefront!

And for more twin resources, look no further than here:

First Trimester Prep Pack
First Trimester Prep Pack


13 Weeks Pregnant Belly


Tips for 13 Weeks Pregnant


Blog Articles


Podcast Episodes


Instagram Posts

We’ve helped thousands of mamas have an even better birth. And we’re on a mission to help millions more!