Pregnancy Week by Week – Weeks 13 to 16

By Stephanie Watson @YourCareE
February 02, 2023
Pregnancy Week by Week – Weeks 13 to 16

Pregnancy week by week: Here's an overview of what you should expect to happen to your body and baby during weeks 13 through 16 of your pregnancy.

You’ve come to the end of your first trimester, and the myriad of changes going on inside your belly will likely be apparent in the baby bump that’s now starting to protrude from under your shirt. The morning sickness from trimester one should have faded by now, and you’re likely settling into your new physical state.

Here’s a look at what’s happening with your baby — and your body — this month.


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Weeks 13 - 14

Depending on how quickly your abdomen has grown, you might be in the market for maternity clothes. Remember that comfort and function are more important than price, especially since you’ll be out of these clothes within a few months. Look for soft fabrics that give and that allow easy access when you need to make bathroom visits, which may be more frequent these days.

Your body

Your morning sickness should have faded by now, but it will be replaced by a few other less-than-pleasant symptoms, like heartburn, constipation, and breast tenderness. Your breasts have not only grown; they’ve also changed. They may feel lumpier than usual. Don’t be alarmed. Usually, the lumps and bumps are your mammary ducts growing in preparation for milk production. Your breasts are already starting to produce the thick, nutrient-rich pre-milk called colostrum that will nourish your baby in the first few days of life.

Your baby

By week 14, your baby will be about 4 inches long and weigh just under 2 ounces — about the size of a peach. Up to now, he’s been all head, or at least mostly head. His noggin made up most of his body, but now he’s starting to look more proportional as his body catches up. The muscles of his face have developed enough that he can form expressions like a frown or squint, although he can’t control them.

Baby’s skin is transparent, revealing a delicate web of blood vessels below. Covering the skin is a fine layer of hair, called lanugo. It will thicken over the next couple of months, and then shed before birth.

His fingers become complete with a set of unique fingerprints. Now that his arms and legs can move freely, you might notice on ultrasound that his thumb has popped into his mouth.


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Weeks 15 - 16

At this point in your pregnancy, you’ve gained about 5 pounds. Stick with your healthy eating plan to keep your weight gain at a steady pace and provide your baby with the nourishment she needs to grow big and healthy.

Your body

As your belly expands, you might start to notice reddish or pinkish streaks running down it. These are stretch marks, and they can appear on your breasts, too. Stretch marks are no cause for alarm. They should fade once your baby is born. In the meantime, you can reduce their appearance by rubbing on a cream made from vitamin E and alpha hydroxy acids. Check with your doctor first, to make sure the product you choose is safe for your baby.

During the second trimester, you might notice that your sex drive has increased. As long as your pregnancy is uncomplicated and your risk for miscarriage is low, it’s perfectly safe for you to have sex. Enjoy the new sensations and the chance to be intimate with your partner. By the third trimester, some women find that their bigger belly makes sex more uncomfortable.

Your baby

Baby’s facial features are beginning to look more recognizable, giving you a glimpse of the person you’ll see on delivery day. Under the surface, her bones are hardening into the skeleton that will support her body as she later runs and jumps.

During your pregnancy visits, your doctor will measure the fundus, the distance between the top of your pubic bone and the top of your uterus. This measurement helps track your baby’s growth. A smaller- or larger-than-normal measurement isn’t necessarily cause for alarm. Your doctor will take an ultrasound to see what’s behind the any discrepancy.

What to remember

Constipation is a common complaint during the second trimester of pregnancy. Pregnancy hormones relax the intestines, preventing digested food from getting pushed through as quickly. One way to relieve the backup is by increasing your intake of high-fiber foods like bran, fresh fruit, and fruit juice. Also drink plenty of water to keep stools soft. If dietary changes alone don’t help, ask your doctor about trying a gentle over-the-counter constipation remedy.


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February 02, 2023

Reviewed By:  

Janet O’Dell, RN