Second Trimester

Week 18: Your Baby is the Size of a Sweet Potato

You are likely feeling regular baby movements now. Your uterus is about the size of a cantaloupe melon. You may notice your belly button starting to pop outward. Backaches may increase as your posture adjusts to your growing belly.

Your baby at week 18

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Size of a Sweet potato

Length: 14.2Weight: 190
Week 1Week 18 of 40Week 40

Baby Development

The baby's ears are now in their final position on the sides of the head and are beginning to stand out. The nervous system is maturing rapidly, and myelin (a protective coating) is forming around the nerves. If your baby is a girl, the uterus and fallopian tubes are formed. If a boy, the genitals may be visible on ultrasound.

Week 18 Highlight: Your baby can now hear sounds! They can hear your heartbeat, your voice, and even loud noises from outside.

Common Symptoms

Leg cramps, especially at night
Swelling in feet and ankles (mild)
Lower back pain
Increased appetite
Feeling baby movements
Stuffy nose

Tips for Week 18

1

Stretch your calf muscles before bed to prevent leg cramps.

2

Elevate your feet when sitting to reduce swelling.

3

Eat bananas and other potassium-rich foods for cramp prevention.

4

Start planning the nursery or baby's sleeping space.

South Africa Specific Info

Start thinking about where you want to give birth. In South Africa, you can deliver at a public hospital or clinic (free), or at a private hospital (covered by medical aid or out of pocket). Research the maternity wards at your nearest hospitals. For public patients, you will deliver at the facility linked to your antenatal clinic.

All Pregnancy Weeks

1st Trimester 2nd Trimester 3rd Trimester

Frequently Asked Questions

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About the Author

Due Date Calculator SA Editorial Team

Our content is reviewed by healthcare professionals familiar with South African maternal health practices. We combine evidence-based medical information with local knowledge to support South African mums throughout their pregnancy journey. Our team includes contributors with backgrounds in midwifery, obstetrics, and maternal health education.

Last reviewed: February 2026