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The Pregnancy Hub

21 weeks pregnant

Get to know your growing baby and the changes you may be feeling.

Choose your week

Week 21

Know your due date?

Enter the due date from your care team to find your estimated week today. Your date stays in this browser tab.

Illustration of a carrot

Second trimester

About the size of

a carrot

Approximate length

10.5 in / 26.7 cm Head to heel

Your baby

Your baby can hear sounds from outside the uterus. Hair and eyebrows continue developing, along with the fine body hair called lanugo. The placenta continues its work supplying nutrients and oxygen and removing waste. Talking or singing can be a way to connect with your pregnancy, without needing to treat a baby's response as a test.

Your body

Your center of gravity changes as your bump grows, which can affect balance and posture. Tasks that once felt easy may require a different position or a break. Comfortable footwear and thoughtful movement can help you adapt your routine. If you feel dizzy, have pain or are worried about falling, discuss that rather than assuming every change is simply part of pregnancy.

This week

Adjusting to changes in balance

Look at a typical day and identify the activity that causes the most discomfort: standing at work, carrying shopping, sitting at a desk or getting in and out of bed. Ask your care team about adjustments that fit that task. If you exercise, ask how to modify activities as balance changes and whether any restrictions apply to your pregnancy. A specific example is easier to address than a general question about staying comfortable. You can also ask whether additional support, such as an assessment of persistent back or pelvic pain, would be useful.

Explore prenatal care

Looking ahead

A question for your next visit

How can I adapt the activities that are becoming uncomfortable as my balance changes?

Browse pregnancy weeks

A little context for these comparisons

These are approximate sizes for each week, not measurements of your baby. Babies and produce both come in different sizes, and the illustrations are not shown to scale.

Before week 20, length is measured from head to bottom. From week 20, it includes the legs, from head to heel. That change explains the jump in length between weeks 19 and 20.

When to get help

If your baby’s usual movements slow down, stop, or change, contact your maternity care team right away.

Seek medical care right away for warning signs such as a severe or persistent headache, vision changes, chest pain, trouble breathing, severe belly pain, vaginal bleeding, leaking fluid, or thoughts of harming yourself or your baby. These are examples, not a complete list. If you cannot reach your care team, seek urgent medical care. Call 911 for a medical emergency.

Read the CDC urgent maternal warning signs (opens in a new tab)
About this guide

Approximate measurements and development information draw on the NHS weekly guides. Linked US health resources support care and preparation topics. The topics are suggestions for discussion, not a schedule of required appointments or tests. Your own care plan may differ.

Every pregnancy is different. Your care team can help you understand your baby’s growth and any symptoms you’re experiencing.