Hard to believe, but by the end of the 16th week of pregnancy, you’ve already reached the end of the 4th month. Your baby would still fit in the palm of your hand—but not for much longer, as they’re growing rapidly. Here you’ll learn what your baby’s development looks like this week and why you might already have butterflies in your stomach.

How big is your baby in the 16th week of pregnancy?

Your baby is about 11 centimeters long this week—about the size of an avocado.

16th week of pregnancy: What's changing for you

Now, as the 4th month of pregnancy comes to an end, your body has finally adjusted to pregnancy, and your hormone levels have stabilized. Your belly can no longer really be hidden: your uterus is growing steadily and is about the size of a honeydew melon in the 16th week of pregnancy. From the outside, your belly is starting to feel firmer. This is because the uterus is moving closer to the abdominal wall and is also becoming firmer to best protect your baby from the outside.

You may now feel a pulling sensation in your lower abdomen. These are the so-called round ligaments—the muscle fiber strands that hold the uterus in position—which are now being stretched. Feeling this is completely normal. You might also notice your baby's acrobatics for the first time this week as a gentle flutter in your stomach when they touch the uterine wall. But don’t worry if you don’t feel anything yet: your baby still has plenty of space to move, and the amniotic fluid provides extra cushioning. Women who have been pregnant before often feel these movements earlier, but by the 20th week of pregnancy at the latest, most expectant mothers will experience them.

16th week of pregnancy: Development of your baby

During this phase of pregnancy, your baby’s thyroid is especially active. It produces more and more hormones that support development. For this, it needs iodine, which you take in through your diet.

Your baby's head, which was still tilted toward their chest not long ago, is beginning to stretch out more and more. At the same time, your baby’s body is steadily growing, so the size ratio between head and body gradually evens out. The joints and muscles are now in their final positions. Your baby still has enough space to kick vigorously in all directions—and takes full advantage of it. They also practice breathing by inhaling and exhaling amniotic fluid, which can sometimes cause hiccups. Their organs continue to mature and grow, and the sweat glands are already present this week. Fine lines are also beginning to form on the fingertips and toe tips—these will develop into
the unique fingerprint of your child.

Maternity wear

Your belly is getting rounder, and your breasts are already larger than at the beginning of your pregnancy. When your usual clothes start to feel tight, you can begin preparing for the rest of your pregnancy (and possibly for breastfeeding, too). You can browse the maternity wear section, but it doesn’t always have to be special pregnancy clothing. Sometimes, comfortable, loose-fitting pieces from the regular collection are enough. Whatever you choose, keep the following points in mind when selecting:

• Choose wide cuts or stretchy fabrics that you can “grow into”—after all, your belly will get a lot bigger.

• Preferably invest in a few high-quality pieces that can be easily combined.

• Pay attention to natural materials like cotton or silk. You’ll sweat less in them, and they feel comfortable on the skin.

• When you buy new tops, make sure they open in the front or can be pulled down. This way, you’re prepared for breastfeeding right from the start.

• Avoid tight bands, for example on socks. These can hinder blood circulation and promote water retention and varicose veins.

• Some well-fitting (nursing) bras are definitely worth the investment. Here, choose preferably those made of soft material so that sensitive breast tissue isn’t additionally irritated. Wide straps and easy adjustability are essential.

This is now important

• For the healthy development of your baby, you should ensure adequate iodine intake. Iodine is found, for example, in iodized table salt, fish, dairy products, broccoli, or lamb's lettuce. It’s best to discuss with your doctor whether taking iodine supplements is beneficial for you. Learn more about which foods are especially good for you right now in the article “ Proper Nutrition During Pregnancy “.

• Do you feel a pulling sensation in your lower abdomen? That is completely normal—you’re probably feeling the stretching of the uterine ligaments. Only if the pain is severe or persistent should you contact your doctor or midwife to be safe.

• The first Maternity wear doesn’t have to be expensive: Just go through your wardrobe and see which pieces are comfortable now and offer space for your growing belly. Maybe some friends also have items from their pregnancy that they can pass on to you.

With our pregnancy calendar, we want to accompany you through this exciting time and provide you with relevant information, created in exchange with our
LILLYDOO experts. Nevertheless, the information listed here can
never replace personal consultation with your doctor or midwife. Always contact your healthcare professional with questions and for professional care.