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13 Weeks Pregnant: Week-by-Week Guide

13 Weeks Pregnant: Week-by-Week Guide

Congratulations! You’re 13 weeks pregnant and beginning your second trimester. You’re in month three and there are incredible developments happening. Check out this week-by-week guide to find out what’s in store for your baby and your body.

  • 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 third 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 seven days! Here are some tips and tricks to keep on top of all that’s happening.

Your baby at 13 weeks pregnant

What’s happening in there

  • The size of a 13-week fetus is equivalent to 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 their thumb as a form of self-soothing.
  • There’s a lot of growing going 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 until sometime between weeks 18 and 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. A small baby bump may become more noticeable.
  • Left brain, meet right brain: Your baby’s corpus callosum began to develop last week, and it will continue to grow through the teenage years. This C-shaped structure communicates information between the left and right halves of the brain.

Where is the baby located at 13 weeks?

Your sweet baby is cozy in the womb, as your uterus is expanding up and out of your pelvis to accommodate the lemon-size 13-week fetus. You’re showing now! Have fun sharing your pregnancy news and getting some cute maternity clothes.

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. You’ve made it through the initial sickness and fatigue, so the second trimester rewards you with a bit of a pep in your step and a higher 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.

7 common week 13 pregnancy symptoms

  1. This is a period of relative calm after what you’ve been through so far, but you may still experience symptoms.
  2. 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.
  3. 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.
  4. Good news, you may have an appetite for sex again.
  5. You may feel pain around your hip or groin area. This is called round ligament pain, caused by your growing belly stretching your ligaments. 
  6. Vaginal discharge will continue throughout your pregnancy.
  7. You may develop chloasma, brownish blotches on your face and neck, commonly called the “mask of pregnancy.” These blotches typically fade after giving birth. 

2 tips for week 13 for a healthy and safe pregnancy

Being 13 weeks pregnant is an important time for you and your baby. Here are some tips on how to adjust to this new stage to keep you and your baby safe.

  • 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 essential for your baby’s brain and eye development.
  • Feeling under the weather: Sniffles and congestion when you're pregnant may just be a symptom, not a cold or virus. Try natural solutions to ease your pregnancy-related congestion.

Week 13 pregnancy checklist

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!

Week 13 Pregnancy To-Do’s Complete

Start exploring childcare options

   Start exploring childcare options is complete

Tell your boss you’re pregnant

   Tell your boss you’re pregnant is complete

Think about how you’ll introduce the idea of your baby if you have other kids

   Think about how you’ll introduce the idea of your baby if you have other kids is complete

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 and know what to do, so 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.