21 Weeks Pregnant: Baby Movement, Heartburn and Symptoms

21 / 40

21 weeks pregnant: movement, heartburn and second trimester changes

At 21 weeks pregnant, you are around 5 months along and well into the second trimester. Many people now feel more clearly pregnant because movements are easier to notice and the bump is more obvious.

Baby’s day-night rhythm may start to become more apparent. You might notice that your baby seems more active at certain times, although the pattern is still developing and can change from day to day.

Week 21 follows 20 weeks pregnant and belongs to the second trimester. Next, read about 22 weeks pregnant, when hearing, sleep and swelling often become more relevant.

Your baby at 21 weeks pregnant

The fetus is often compared with a carrot or banana and may measure around 26-27 cm long, though size estimates vary. The baby is swallowing amniotic fluid, practising breathing motions and moving with increasing coordination.

Sleep cycles are starting to become more noticeable, and you may be able to tell when the baby is quiet or active. The senses are maturing, and the baby continues to store iron and build stronger bones and tissues.

If you already had your anatomy scan, 21 weeks may be a good time to review the results and ask any follow-up questions. If a repeat scan was recommended, this can be a normal part of getting clearer views.

Your body and symptoms

Heartburn is common because the growing uterus can push upward on the stomach and pregnancy hormones can relax the valve between the stomach and oesophagus. Smaller meals, avoiding trigger foods and staying upright after eating may help.

You may also notice a growing appetite, a larger shoe size, backache, round ligament pain, constipation, nasal congestion, stretch marks or more frequent urination. These changes can be uncomfortable but are often normal.

If heartburn is severe, if food feels stuck, or if you have pain, vomiting, bleeding, shortness of breath or symptoms that worry you, contact a healthcare professional.

Ideas

Track the times of day when your baby seems most active so you can notice patterns later.
Eat smaller meals and avoid lying down right after eating if heartburn is bothering you.
Use a supportive pillow setup when sleeping on your side if your body feels less comfortable at night.
Talk through any scan findings or follow-up questions with your midwife or clinician.
Use the pregnancy calculator if you want to compare 21 weeks with your estimated due date or months pregnant.

Frequently asked questions about 21 weeks pregnant

How many months is 21 weeks pregnant?

Twenty-one weeks pregnant is often described as about 5 months pregnant. Weeks are more accurate than months, so providers usually keep using week-based dating.

What trimester is 21 weeks pregnant?

At 21 weeks pregnant, you are in the second trimester.

How big is the baby at 21 weeks pregnant?

Size estimates vary, but the fetus is often around 26-27 cm long and may be compared with a carrot or banana.

Can baby movement feel regular at 21 weeks pregnant?

You may feel clearer movements now, but a regular daily pattern is still developing. Many people notice stronger kicks later in the second trimester.

What should I do about heartburn at 21 weeks pregnant?

Eat smaller meals, avoid trigger foods if they bother you, stay upright after eating and speak with your clinician before taking medicines if heartburn is frequent or severe.