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13 Weeks Pregnant: Week-by-Week Guide
4 mins read

IN THIS ARTICLE – At this stage of your journey, new developments are beginning to unfold. Check out this week-by-week guide to find out what’s in store for your baby and your body in week 13 of pregnancy.


Your baby at 13 weeks pregnant | Week 13 pregnancy symptoms | 2 expert tips for a healthy and safe pregnancy | Week 13 checklist: How to plan your pregnancy



  • 13 weeks pregnant is which trimester? Second trimester
  • How many weeks of pregnancy are left? 27 weeks
  • How many months is 13 weeks pregnant? You’re in your second month.

With week 12 of your pregnancy complete, you’re on week 13. Enjoy it, as week 14 is on the horizon! 

One of the most exciting things about pregnancy is how many changes you’ll experience with your little one over the span of just 7 days! Here’s some tips and tricks to keep on top of all that’s happening.

Your baby at 13 weeks pregnant

What's happening in there

  • Your baby is the size of a lemon.
  • You’re officially at the start of the second trimester.
  • The countdown continues: you’ve got 27 weeks to go!

What happens during the 13th week of pregnancy?

  • Smiley or frowning: Your little one’s mouth muscles are slowly developing and at week 13, can form a smile or frown. Your baby may also start to suck on the thumb as a form of self-soothing.
  • There's a lot growing on: Bone tissue is forming in their arms, legs and around your little one’s head, along with functioning nerves, muscles and organs.
  • Warming up the pipes: Your baby’s vocal cords are developing and will be ready to make some noise before you know it. Speaking of noise, week 13 is when many parents-to-be typically start to share their good news with close friends and family members.
  • The waiting game: Although your baby’s genitals are growing, they are still hard to discern on an ultrasound. You’ll have to hold out to weeks 18 to 23 to get the news you’ve been waiting for.
  • The bump is growing: Now that your baby is moving up and out, so is your tummy. You may even find people offer their seats on the bus or train.
  • Left brain, meet right brain: Your baby’s corpus callosum began to develop last week and it will continue to grow through to teenage years. This c-shaped structure communicates information between the left and right halves of the brain.

What should I be feeling at 13 weeks pregnant?

  • Now that you can hear your baby’s heartbeat at prenatal visits and your belly is growing, you will start to feel a real connection with your little creation.
  • You’re probably going to feel a little more energized. Now that you’re through the initial sickness and fatigue, the second trimester rewards you with a bit of a pep in your step, and if you’re lucky, more sex drive.

How big is your baby at 13 weeks pregnant?

 13 Weeks Pregnant

Baby Weight

1 ounce

Baby Length

3 inches

Baby Size

Comparable to a lemon


Week 13 pregnancy symptoms

During week 13 of pregnancy, your body is changing quickly. As your baby grows, you will too, and there are certain pregnancy symptoms you may experience at this time.

4 common week 13 pregnancy symptoms

  • This is a period of relative calm after what you’ve been through so far, but you may still experience symptoms.
  • You may notice some vaginal discharge called Leukorrhea. It’s part of the body’s efforts to protect the birth canal and keep it free of infection. The milky discharge is a byproduct of estrogen production.
  • There’s every chance you may still get a combination of indigestion, constipation or heartburn, so be wary of the foods and drinks that cause these discomforts.
  • Good news, you may have an appetite for sex again.

2 expert tips for a healthy and safe pregnancy

Being 13 weeks pregnant is an important time for you and your baby. Here’s some more expert-recommended advice on how to adjust to this new stage and keep you and your baby safe.

  1. Eating for two?: The whole “eating for two” thing hasn’t quite started yet. You only need an extra 300 calories a day to support your baby’s development, so indulge those prenatal cravings in moderation. Most of those calories should be coming from healthy, whole foods, including sources of the healthy fat DHA (docosahexaenoic acid) which is important for your baby’s brain and eye development.
  2. Feeling under the weather: Sniffles and congestion when your pregnant may just be a symptom, not a cold or virus. Try natural solutions to ease your pregnancy-related congestion.

Week 13 checklist: How to plan your pregnancy

Knowing what to do week-by-week can help you feel prepared and alleviate stress. Add these new items to your to-do list this week. You’ve got this, mama!

To-Do Checklist
Start exploring childcare options
Tell your boss you're pregnant
Think about how you'll introduce the idea of your baby if you have other kids


Learn more about your pregnancy, including pregnancy planning and pregnancy nutrition to feel prepared to continue this magical adventure. You’re armed with the facts, what to do, and now you can take time to connect with the little one growing inside you.

 With week 12 in the rearview mirror and week 13 going strong, look to the future and what's coming up in week 14!

Join Enfamil Family Beginnings

It’s your 13th week of pregnancy, and you and your baby are experiencing exciting changes every day. Prepare for your new arrival with help from Enfamil Family Beginnings. It’s the perfect resource for new and expecting moms. Save on Enfamil products, track your bump and baby’s growth, and get helpful articles each week relevant to your journey. Join now for up to $400 in free gifts.

All information on Enfamil, including but not limited to information about health, medical conditions, and nutrition, is intended for your general knowledge and is not a substitute for a healthcare professional's medical identification, advice, or management for specific medical conditions. You should seek medical care and consult your doctor or pediatrician for any specific health or nutrition issues. Never disregard professional medical advice or delay seeking medical treatment, care, or help because of information you have read on Enfamil.