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Pregnancy at week 21

4-minute read

Your baby

Your baby now weighs about 390g and measures 18cm from head to bottom – about the size of a large banana. They are surrounded by amniotic fluid and have plenty of room to move around inside the uterus. They may be kicking you hard enough for your partner to feel by now. Also, their brain is developing rapidly.

Your baby’s arms and legs have grown and now look more in proportion to the rest of their body. There is soft hair on the baby’s head; they have eyebrows; and their body is covered in fine hair (lanugo). In girls, the uterus is formed and in boys, the testicles.

Your baby at 21 weeks


Your body

Your growing uterus might be putting pressure on your stomach, leading to heartburn or indigestion. This is very common in pregnancy. You can improve how you feel by eating smaller meals, avoiding foods that you know trigger your symptoms, and by raising your head when you lie down.

If your heartburn is very bad and it’s not helped by lifestyle changes or medications from the pharmacy, then mention it to your doctor or midwife. It could be the sign of something more serious such as pre-eclampsia.

Other common pregnancy discomforts you might have at this time include bloating and gas, as well as changes to your appetite. Try not to eat too much – have small, nutritious meals as part of a healthy diet). You might also experience varicose veins, backache, bleeding gums and stretch marks at this time.

Things to remember

The second trimester is a good time to travel since you may not be able to do so later in your pregnancy. If you decide to go away, you will need to take a few precautions.

If you have a normal, healthy pregnancy, there’s no reason why you cannot fly up until 32 weeks into the pregnancy. Always check with the airline and your travel insurer before you go. You are more at risk of deep vein thrombosis (DVT) when you’re pregnant, so it’s important to keep walking around the plane and to wear compression stockings on long flights.

If you’re driving, it’s very important - as well as required by law - to wear a seatbelt in the car. Put the lap part underneath your bump.

Always take care with what you eat and drink while you’re pregnant, especially if you’re overseas. If in doubt, always drink bottled water and make sure you stay well hydrated in hot climates. See a doctor straight away if you get sick.

Read next

Pregnancy at week 22

Your pregnancy at 22 weeks

Learn about your pregnancy journey and what is happening to you and your baby.

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Last reviewed: April 2022

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