20 Weeks Pregnant: Pregnancy Symptoms & Baby Development

It might be hard to believe, but at 20 weeks pregnant you’re now halfway through your pregnancy. With your baby focused on growing bigger and putting on weight, you might be getting ready to see them again on screen at your 20-week scan. This is also known as the anomaly scan, and if you choose to do so you can find out your baby’s sex¹.

Let’s explore some of the developments happening for your baby this week, and some of the common pregnancy symptoms - including leg cramps, heartburn and constipation. We’ll also look at the changes happening to your body at 20 weeks pregnant, and why iron is vital to a healthy pregnancy diet.

During the second trimester, there’s a lot going on in terms of foetal development. Your baby is becoming more active, and you may already be feeling them rolling and tumbling as they punch, kick and turn in your uterus². At this point in your pregnancy, your baby’s focus will be to continue putting on weight as they get ready for birth.

If you’re having a baby girl, her uterus will be developing, and her ovaries will already have seven million primitive eggs in them - two million of which she’ll be carrying at birth³. If you’re having a baby boy, then this is the week when the testes start lowering from his abdomen, dropping into the scrotum from 26 weeks⁴.  

At 20 weeks pregnant, your baby (still referred to as a foetus) measures approximately 25.6 cm long and is around the size of a banana². Your baby is now measured from their head to the heels of their tiny feet. This is instead of head to bottom, a measurement used earlier on in pregnancy when your baby’s legs were curled up and difficult to see².

Your baby’s skin will now be covered with vernix (also known as vernix caseosa), a fatty, white and greasy substance. Because your baby will spend nine months floating in amniotic fluid, vernix protects your baby’s skin from drying out. It will also make it easier for your baby to ease down the birth canal when you go into labour².  

This week, it might be time for you to attend your 20-week scan if you’ve opted to have one. Carried out by a sonographer at anywhere between 18 and 20 weeks, the 20-week scan is also known as the anomaly scan, or the anatomy scan. It’s an important part of your antenatal care as it will be able to determine a number of things about how your baby is developing physically.

The anomaly scan is also an opportunity for the sonographer to check that your placenta is functioning correctly¹.

It’s important to understand that the anomaly scan is ultimately a medical examination, and looks closely at your baby's abdomen and kidneys, spinal cord, bones, heart and brain. Whilst it can’t pick up on every condition, it will check for conditions including¹:

• Spina bifida
• Cleft lip
• Serious heart abnormalities
• Edwards’ and Patau’s syndrome
• Anencephaly

You’ll be supported throughout the ultrasound scan; in most cases, everything will be as it should be. However, if there’s a cause for concern, a doctor may come and take a closer look and you’ll be guided and advised about any next steps.

If you’d like to know your baby’s sex, you should be able to find this out at the 20-week scan.

Now that you’re halfway through your pregnancy, let’s take a look at some of the symptoms that you might be experiencing.

Exercising during your pregnancy has a number of benefits for you and your baby. As long as you haven’t been advised otherwise by your doctor or midwife, there’s no reason why you can’t fit regular exercise into your daily routine¹⁴.

Whether you’re already doing regular exercise, or you’re a complete beginner, it’s always a good idea to run your intended exercise plan by your healthcare provider. That way you’ll know you’re exercising at a level that’s right for you. 

As a general rule of thumb, you should be able to easily have a conversation during exercise, so if you find yourself struggling for breath, it’s a sign that you’re overdoing things. Read more about exercising safely in pregnancy here.

You could try:

• Walking for 30 minutes every day¹⁴. If you can’t manage that amount, do what feels comfortable for you, as any level of exercise is beneficial
• Yoga. Pregnancy yoga will help to ease tension, relax your muscles and enable you to practise some breathing techniques¹⁵
• Swimming. Swimming is a really good pregnancy exercise as it will support the weight of your growing bump¹⁵

At 20 weeks pregnant, you’ll have decided whether you wish to have your anomaly scan. If you’ve chosen to do so, think about whether you’d like anyone to come with you, and have a read about what’s involved and what to expect.

If you’re struggling with some of the things you’re advised to avoid in pregnancy, for example smoking or your caffeine and alcohol intake, now is the time to have a chat with your midwife about strategies that can help.

If you’re planning to attend an antenatal class, you should start exploring what’s available in your local area. Your midwife may be able to help here, and let you know your options.

Other things to think about include:

• Making a birth plan
• Ensuring that you are eating a healthy balanced diet
• Deciding whether to have a birth partner present when your baby is born
• The things you will pack in your hospital bag - you can download our handy checklist here