By moms. For moms.

18 Weeks Pregnant: Symptoms & What to Know

18 Weeks Pregnant: Symptoms & What to Know

pregnancy week 18


18 weeks pregnant is month 5 of your pregnancy. Leg cramps and other not-so-fun symptoms are likely to linger as your pregnancy progresses week by week, but can you believe you only have a few more months left to go?

During week 19 or week 20, you should have a mid-pregnancy ultrasound to monitor fetal movement and fetal development, also known as the 20-week anatomy scan. If this is your first ultrasound, it may be used to confirm your due date, according to the American College of Obstetricians and Gynecologists (ACOG).

Your baby at week 18 is as large as a cucumber! They can now yawn and hiccup, which you might start feeling soon. If you haven’t felt your baby's movements yet, don't worry. There are several factors that determine when you'll feel your baby move (like your weight and muscle tone). Many women don't report feeling their babies move until 23 or 24 weeks of pregnancy, and those jabs and kicks will come as your baby continues to grow over the next few months.

How big is my baby? 18 weeks

18 Weeks Pregnant Symptoms

Bloating and Gas

The hormone progesterone may be to blame if you’re feeling bloated or gassy. Progesterone causes the smooth muscle tissue in your body to relax, which leads to slower digestion. While that’s good news for your baby, since they get more time to absorb nutrients, it may cause you to feel bloated and even have a cramp or two. 

Your growing uterus also puts pressure on your rectum, which might lead to passing more gas than you’re used to. Stay hydrated and make sure you’re getting enough fiber to help avoid constipation and the buildup of painful gas.

fiber while pregnant


During your pregnancy, you may experience swollen feet or ankles, also known as edema. The amount of swelling you experience can vary depending on the time of day (increasing in the evening) and even the weather (warmer weather can mean more swelling).

Edema occurs when bodily fluids increase and accumulate in your tissue thanks to increased blood flow and your growing uterus putting pressure on your pelvic veins and vena cava (the large vein on the right side of your body that helps blood go from your lower limbs to your heart). 

This common symptom, which affects about three-quarters of pregnant women, can typically be seen in the feet and ankles, but you may feel it in your hands. Once it appears, this swelling is likely to stick around until you give birth. 

While mild swelling is completely normal, check with your doctor if you have swelling that doesn’t go away overnight or if your face becomes puffy. Preeclampsia usually appears as excessive swelling combined with other symptoms such as elevated blood pressure and rapid weight gain.

Health care professionals suggest that watching your salt intake, drinking lots of water, and avoiding long periods of sitting or standing may help reduce swelling in pregnancy.

Baby on Board

At 18 weeks, your baby measures about 5½ inches long and weighs 5 to 6½ ounces.

Under Construction: The Nervous System

Your baby’s nervous system is maturing rapidly at this stage in their growth. A network of nerves is forming more complex connections from nerve cell to nerve cell. These nerves are assisted by a substance called myelin, which helps speed up messages between cells.

There’s a lot going on in your baby’s brain too. There, cells are starting to develop to one day help your baby with their senses: touch, taste, smell, sight, and hearing.

best gender reveal

Under Construction: Girl or Boy?

If you don’t already know whether you’re having a boy or girl, you may be able to find out at your next ultrasound. By 18 weeks, a boy’s genitals may be visible on screen while a girl’s fallopian tubes and uterus are in their proper positions. 

If you chose to learn your baby’s gender before birth, you may find out at your 20-week anatomy scan. Check out these unique gender reveal ideas if you plan on sharing the sex of your baby with friends and family.

best maternity bra

What to Wear This Week

Whether you’re trying to stay active during your second trimester or just like the support of a sports bra, check out our roundup of the 3 Best Maternity Sports Bras for 2022. We might be biased, but we think the BFF Hands-Free Pumping & Nursing Bra is pretty incredible for both pregnancy and postpartum.  

If you have any questions about how to get the right bra fit, contact our Customer Care Team. They'd love to help you find a great-fitting bra that provides the comfort and support you deserve during every season of motherhood!

Looking for more great maternity activewear? We love the Louisa Maternity & Postpartum Support Leggings, which are designed to never lose shape, even as your shape changes. 

best maternity leggings

This information is for educational purposes only and does not constitute medical advice that has been medically reviewed. Please reach out to your doctor or midwife with any questions.

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