12 Weeks Pregnant: Week-by-Week Guide
12 Weeks Pregnant

12 Weeks Pregnant: Week-by-Week Guide

Congratulations! You are 12 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 12 of pregnancy.

At 12 weeks pregnant:

  • Your baby is the size of a lime
  • You’re officially at the last week of your first trimester
  • The countdown continues: you’ve got 28 weeks to go!

What happens during the 12th week of pregnancy?

Things are moving fast in your uterus. Over the last week, your baby’s fingers and toes have formed and your baby has grown to about 2.5 inches in length.

  • All systems go most of your baby’s internal systems are formed, the kidneys are functioning and can turn any amniotic fluid consumed into urine. That little abdomen is now large enough to hold the intestines and the digestive muscles are contracting in preparation for being able to eat and digest after birth. Their liver is producing blood cells now too, helping to really accelerate development.
  • Get ready to make some noise at week 12, your baby’s vocal chords are developing, preparing for giggles, gurgles and the inevitable crying when you finally meet.
  • Prepping for that close up by week 12, your baby’s profile is evident on a sonogram, with all the changes to their face now discernible.
  • The internal computer has started up the corpus callosum is developing. This is a bundle of 200 million axons, or nerve fibers, that coordinates motor, sensory, and cognitive functions between the right and left sides of the brain.

What should I be feeling at 12 weeks pregnant?

  • You’re going to feel the love the first time you hear your baby’s heartbeat. It’s usually audible during checkups at the 12th week mark.
  • You will feel bloated as your intestines are unceremoniously moved out of the way by your hungry little baby, pushing up against you, coupled with the effects of progesterone. This pregnancy hormone is responsible for slowing down your digestive system to give more time for the nutrients to be absorbed into your blood and passed through to your baby.
  • You’re going to be tired a lot more. You are now working 24/7 to not only fuel your baby’s growth, but also to produce the placenta. It’s a small miracle, but anytime you feel you’re exhausted, take a little ‘you time’ while you still can.
  • Hopefully the constant urge to pee will have passed by week 12.

12 Weeks Pregnant Facts

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

Baby Size at 12 Weeks
Baby Weight 0.5 ounces
Baby Length 2 - 2.25 inches
Baby Size Comparable to a lime or a plum

Week 12 Pregnancy Symptoms

During week 12 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 12 pregnancy symptoms on your radar:

  • You’re a gas machine burping, bloating and flatulence are part of the side effects of pregnancy hormones which relax the digestive tract. Avoid beans, fizzy sodas, candy, and fried foods.
  • Hooray, you’re not feeling sick — instead, welcome to progesterone’s new trick — dizzy spells. This pregnancy hormone can cause your blood vessels to widen to increase blood flow to your baby, but it slows its return to you, causing lower blood pressure and light-headedness.
  • You may be producing excessive saliva — it’s an odd symptom, but rather than drooling try chewing gum!
  • Your sex drive can drop considerably — it’s totally understandable at this point as your body is playing so many tricks on you both physically and emotionally.


Being 12 weeks pregnant is an important time for you and your baby. Get advice on how to adjust to this new stage.

  • Now your baby’s brain and nerves are developing rapidly, you need to fuel that with the right foods. Combine a healthy diet with prenatal vitamins that include DHA (docosahexaenoic acid) to nourish your baby’s fine motor development and vision.
  • Your joints are probably loosening up from a hormone called relaxin. This will eventually aid the opening of your cervix, but for now it can also loosen ligaments throughout your body, making you more prone to injury  so slow and steady whether you’re working out or lifting the groceries.
  • Be sure to get a flu shot  the CDC recommends vaccination for all moms-to-be.

Week 12 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
Learn what food to avoid
If you haven’t already, quit alcohol
Choose some looser fitting clothes

If you’re interested in learning more about your pregnancy, explore our resources on your first trimester and special nutritional needs.