13 Weeks Pregnant: Week-by-Week Guide

    13 Weeks Pregnant: Week-by-Week Guide

    Congratulations! You are 13 weeks pregnant. At this stage of your journey, new developments are beginning to unfold. Explore our week-by-week guide to find out what’s in store for your baby and your body in week 13 of pregnancy.

    At 13 weeks pregnant:

    • 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 chords 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.

    Baby Size: Fast Facts

    How big is your baby? Check out the chart below to find out!

    Baby Size at 13 Weeks
    Baby Weight 1 oz
    Baby Length 3 inches
    Baby Size Comparable to a lemon

    Week 13 Pregnancy Symptoms

    During week 13 of pregnancy, your body is adjusting to the new life it’s supporting. As your baby changes, you will too, and there are certain pregnancy symptoms you may experience at this time. Keep these week 13 pregnancy symptoms on your radar:

    • 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.


    Being 13 weeks pregnant is an important time for you and your baby. Get advice on how to adjust to this new stage.

    • 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.
    • 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: Plan Your Pregnancy

    Be prepared. Explore our pregnancy checklist below and add these items to your to-do list this week.

    To-Do Complete
    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.

    If you want to learn more about your pregnancy, explore our resources on life in the second trimester or read on about week 14.