This is a big week for your baby: Your little one's key body systems and vital organs have formed! If you haven't already, you'll be able to hear fetal heart activity at your next prenatal checkup.
Meanwhile, at 12 weeks pregnant, your baby bump may be looking a little more pronounced.
Your Baby at Week 12
At a Glance
12 weeks pregnant is how many months?
If you're 12 weeks pregnant, you're in month 3 of your pregnancy. Only 6 months left to go! Still have questions? Here's some more information on how weeks, months and trimesters are broken down in pregnancy.
How big is my baby at 12 weeks?
By now your baby weighs a full half-ounce, with a crown-to-rump length of 2 to 2¼ inches: about the size of a lime.
It's hard to believe — especially from the outside, since you're probably barely showing at this point — but your baby has more than doubled in size during the past three weeks.
Baby’s digestive system begins working
This week marks a turning point for your baby. At 12 weeks pregnant, the Herculean task of developing new bodily structures is nearing an end, as most of your baby's systems are fully formed — though there's still plenty of maturing to do.
Now comes the maintenance phase, during which your fetus' systems continue to evolve for the next 28 weeks and the organs get to work. For one thing, the fetal digestive system is beginning to flex its muscles — literally — as it starts practicing contraction movements, a skill your little peanut will need after birth to push food through the digestive tract.
The bone marrow is busy making white blood cells — weapons that will one day help your baby fight infection once she's out of your safe haven and in a regular play group. And the pituitary gland at the base of the brain has started producing the hormones that'll enable her to make babies of her own in a few decades or so.
Fetal cardiac activity ramps up
If you haven't already had the pleasure, it's likely that at this month's checkup you'll hear sounds of fetal cardiac activity — a noise that will make your heart race with joy!
Your Body at Week 12
The end of some pregnancy symptoms
As you near the end of your first trimester, your uterus, now about the size of a large grapefruit, begins to migrate from the bottom of your pelvis to a front-and-center position in your abdomen.
If you're lucky, this will bring an end to one pesky early pregnancy symptom: the constant urge to urinate.
Also slated to diminish somewhat now that you're on the cusp of your second trimester are some of those other early pregnancy symptoms: nausea, super tender breasts and nipples, food aversions and fatigue.
Your 12 weeks pregnant belly
At 12 weeks, your baby bump may be more pronounced and may even show to the outside world. But it’s just as likely that while your clothes may be getting a little tight, you won’t yet have a noticeably pregnant belly at this point. If anything, you may look like you’ve gained a little weight around the middle, or you may not look different to anyone else at all.
Whatever the case may be, know that your 12 weeks pregnant belly is completely normal, whether it’s on the bigger, smaller or invisible side. Baby bumps can vary widely depending on the woman’s size and shape and whether this is a first or subsequent pregnancy.
So don’t fret if your bump at 12 weeks doesn’t look like your pregnant friend’s at the same stage. All bumps are beautiful! If you’re not showing yet, you will be in time, and if you are showing quite a bit, that’s fine too. You can always talk to your practitioner if you have any concerns.
Dizzy spells
Once you hit your second trimester, there's a new pregnancy symptom that may be added to the mix: dizziness. And guess who's to blame? Yup — it's your old friend progesterone again, which causes your blood vessels to relax and widen around 12 weeks pregnant, increasing the flow of blood to your baby (again, good for baby), but slowing the return of blood to you (as always, not so good for mom).
What that means for you is lower blood pressure and reduced blood flow throughout your body, including to your brain. These factors can contribute to that light-headed, dizzy feeling — especially when you get up too quickly — which is why slow and steady wins the race here.
Another cause of dizziness during pregnancy is low blood sugar levels, which can occur if you're not eating regularly. So don't try to run…or even walk…on empty.
Here's a quick tip: If you feel dizzy or faint, lie down or sit with your head lowered between your knees, take deep breaths and loosen any tight clothing — like that button on your jeans you struggled to close in the first place. As soon as you feel a little better, get something to eat and drink.
Low sex drive
Your best friend says being pregnant has seriously boosted that good old libido — but you aren't feeling any friskier. What's the deal with your decreased sex drive?
Hormones hit every woman differently, meaning a spike in sex drive for some and a damper on it for others. Pregnancy symptoms can also stand between you and a good time — after all, it's hard to get in the mood when you're queasy, tired or constipated (or all of the above and then some!).
Rest assured, whatever you’re feeling is normal. Just stay emotionally connected with your partner and remember that many women have ups and downs in sex drive throughout pregnancy. So you may be in for a warmer spell soon.
Pregnancy Symptoms Week 12
Tips for You This Week
All pregnant women are with child sometime during flu season, October to May, which is why the Centers for Disease Control and Prevention (CDC) recommends that all moms-to-be get the flu shot. And being pregnant doesn’t up your risk for shot side effects, notes a recent study.
Your doctor can feel your growing uterus by touching your abdomen, but your belly may not be sporting a bump. Until you're ready for maternity wear, shop for looser or stretchy clothes, like empire-waist maxi dresses, drawstring pants and lightweight sweaters.
Pushing your baby through your pelvis and into the world is demanding not only on you, but also on your pelvic floor muscles — which have to stretch to proportions previously unimaginable.
Doing pelvic floor exercises can ease pregnancy symptoms and lead to a faster post-birth recovery. Squeeze the pelvic floor muscles for up to 10 seconds, shooting for three sets of 20 a day.
Building these bladder- and uterus-supporting muscles reduces your chance of bladder issues and eases a host of other pregnancy and postpartum symptoms.
The warning labels on the sides of beer, wine and alcohol bottles are there for a reason. Drinking alcoholic beverages during pregnancy can have serious consequences for your baby, including birth defects and complications.
Even moderate drinking can cause problems, so it's best to abstain entirely until after delivery. Don't worry, however, if you had a couple of drinks before you found out you were pregnant.
Shaving might be a cinch right now, but as your pregnancy progresses, you might have trouble seeing below your belly or keeping your balance. While a shower can soften your hair and skin, making it easier to remove, always shave after you've finished, since a slip-up could be serious.
If your skin isn't too sensitive, you might want to try waxing and sugaring (ask your doctor if it's okay first), which is a long-term solution to unwanted hair.
As for bleaches and hair removal creams and lotions, the jury is still out on whether they're safe to use during pregnancy, so consider shelving them until after you give birth.
Here's one bottle you need to be hitting: the water bottle. It's more important than ever to stay hydrated now, so plan on adding an extra glass of liquid for every half hour of activity — and no cheating...it should be an 8-ounce glass.
Stick to water when possible — sports drinks contain too many ingredients you just don't need. Take in even more in warm weather or when you're just plain sweating a lot.
Fortunately, you don't have to worry about finding unpasteurized milk at the supermarket, thanks to the Food and Drug Administration (FDA).
But you can run across soft cheeses that have been made with unpasteurized milk — and those can harbor listeria and other pathogens.
To stay safe, don’t nosh on feta, Brie, Camembert, goat cheese, blue-veined cheeses and queso fresco unless you’re positive they’re made with pasteurized products. Always check the label to make sure.
For a safer alternative, stick with hard cheeses (like Swiss and cheddar) or heat up soft cheeses until bubbly.
Reviewed September 30, 2022 From the What to Expect editorial team and Heidi Murkoff, author of What to Expect When You're Expecting. What to Expect follows strict reporting guidelines and uses only credible sources, such as peer-reviewed studies, academic research institutions and highly respected health organizations. Learn how we keep our content accurate and up-to-date by reading our medical review and editorial policy.
- What to Expect When You’re Expecting, 5th edition, Heidi Murkoff.
- WhatToExpect.com, Can You Drink Alcohol While Pregnant?, May 2021.
- WhatToExpect.com, Help Me, Heidi! What Cheeses Are Safe to Eat During Pregnancy?, October 2019.
- WhatToExpect.com, Kegel Exercises: How, When and Why to Do Your Kegels During and After Pregnancy, November 2019.
- WhatToExpect.com, How Much Water Should You Drink During Pregnancy?, December 2020.
- WhatToExpect.com, The Flu Shot and Pregnancy, February 2021.
- WhatToExpect.com, How to Remove Hair During Pregnancy Safely, March 2021.
- Stanford Children’s Health, The First Trimester, 2021.
- National Institutes of Health, National Library of Medicine, Fetal Development, June 2021.
- KidsHealth From Nemours, Week 12, 2021.
- Mayo Clinic, Fetal Development: The First Trimester, June 2020.
- Oxford University Press, Lachman’s Case Studies in Anatomy, 2013.
- American Heart Association, Circulation, Cardiovascular Physiology of Pregnancy, September 2014.
- National Institutes of Health, National Library of Medicine, Dizziness and Vertigo, June 2021.
- Mayo Clinic, Orthostatic Hypotension (Postural Hypotension), October 2020.
- Merck Manuals, Low Blood Pressure, November 2020.
- American College of Obstetricians and Gynecologists, Your Sexual Health, July 2019.
- National Institutes of Health, National Library of Medicine, Kegel Exercises — Self-Care, June 2021.
- American College of Obstetricians and Gynecologists, Pelvic Support Problems, January 2020.
- Mayo Clinic, Kegel Exercises — A How-to Guide for Women, September 2020.
- American College of Gastroenterology, Belching, Bloating, and Flatulence, 2021.
- Centers for Disease Control and Prevention, Flu & Pregnant Women, April 2021.
- American College of Obstetricians and Gynecologists, Obstetrics & Gynecology, Inactivated Influenza Vaccine During Pregnancy and Risks for Adverse Obstetric Events, September 2013.
- American College of Obstetricians and Gynecologists, Alcohol and Women, March 2020.
- FoodSafety.gov, People at Risk: Pregnant Women, September 2020.
- Food and Drug Administration, Mercury Levels in Commercial Fish and Shellfish (1990-2012), October 2017.
- Mayo Clinic, I’ve Heard That Salmon Is High in Dangerous PCBs. So What Are PCBs and What Risk Do They Pose?, August 2020.
- Food and Drug Administration, Listeria From Food Safety for Moms to Be, September 2018.
- Food and Drug Administration, The Dangers of Raw Milk: Unpasteurized Milk Can Pose a Serious Health Risk, November 2018.
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