21weeks
pregnant

Medically reviewed by Clare Herbert, Senior midwife and team leader

Written by Chess Thomas

IN THIS ARTICLE

Highlights this week

Get to know your baby's usual pattern of movements.

Can anyone have a home birth?

Get ideas and inspiration for your baby’s name.

Baby development at 21 weeks

Your baby now weighs about 399g (14.1oz) and is nearly 27.4cm (10.8in) long (Hill 2019). This is about as long as a carrot.

His skin is transparent and gradually turning darker as capillaries, the smallest type of blood vessel, form underneath (Hoath and Mauro 2015, Moore et al 2019a). Their eyebrows and head hair are becoming thicker and easier to see (Moore et al 2019a, Visembryo 2014a, b).

Your baby’s busy making facial expressions, including mouthing, yawning, and sucking (Sato et al 2014). They may soon be having a work-out, as their initial fluttering movements turn into fully fledged kicks and nudges (Hijazi and East 2009). All this activity may soon develop apattern, as they have short, frequent phases of being awake and asleep (Hijazi and East 2009, RCOG 2019).

The placenta has been growing throughout your pregnancy, and until this week, has been heavier than your baby (NHS 2018). From this point, your baby’s growth will outweigh the placenta’s (NHS 2018), although the placenta will continue to grow and provide nourishment until your baby reaches full term (Moore et al 2019b).

baby with newly formed eyebrows and permanent fingerprints

Your baby at 21 weeks

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Your baby is the length of a carrot

length

27.4

head to toe

weight

399

grams

Pregnancy symptoms at 21 weeks

As you adjust to your changing size, a little clumsiness is to be expected. You're carrying more weight, your centre of gravity has changed, your joints are loose and your muscle coordination is reduced. It's no wonder that you keep bumping into things!

Although clumsiness is a common pregnancy symptom, it will still give you a fright if you fall over. Rest assured that your baby is well protected in their amniotic sac. It's unlikely they’ll be hurt, but contact your midwife or GP to let them know what's happened. This is particularly important if you have rhesus negative blood.

If you're feeling clumsy and have other symptoms, such as pain, blurred vision or swollen hands and feet, you should see your GP or midwife. They may be a normal part of your pregnancy, but they can also be signs of pre-eclampsia. It's best to get yourself checked over just in case.

baby in body with uterus pushing against intestines

Your body at 21 weeks

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What you need to know at 21 weeks pregnant

It’s a good time to think about the kind of birth you'd like. If you're worried about interventions, such as an episiotomy or assisted birth, talk to your midwife about how you can increase your chances of a straightforward birth. At the same time you can also talk to them about where you'd prefer to give birth. You might want to opt for a midwife-led unit or even think about having a home birth.

Many women find that being in warm water helps them to cope with the pain of contractions more easily. So you may want to consider having a water birth or using a pool for part of your labour. As long as your pregnancy is going well, having a water birth is perfectly safe. See if it’s right for you, and ask your midwife what your options are in your local area.

"I had a tour of my nearest midwife unit. They make such an effort to make it homely with music players and comfy armchairs. If I can, I hope to give birth there."

Ellie

If you’d prefer to have access to pain relief such as an epidural, or if you have complications during your pregnancy, it may be better for you to give birth in a hospital. Find out more about the advantages and disadvantages of hospital birth.

Your pregnancy to-do list at 21 weeks

Pregnancy can make simple movements feel uncomfortable. Find out how to sit and stand up without hurting your joints.
Watch our video to see how your baby will develop between now and 27 weeks.
Discover whether it's safe to continue wearing your piercings during pregnancy.
If you're receiving extra care during your pregnancy, join our high-risk care community groupOpens a new window for friendly advice.
Get the facts about urinary tract infections and how they're treated.

Check out the BabyCentre podcast!

The Parent Pod is BabyCentre’s brilliantly entertaining and informative podcast series. Join hosts Claire and Lucy as they walk your exciting journey with you each week from early pregnancy until your baby is 12 weeks old. Subscribe now on the usual channels. Learn more

Sources

BabyCentre's editorial team is committed to providing the most helpful and trustworthy pregnancy and parenting information in the world. When creating and updating content, we rely on credible sources: respected health organisations, professional groups of doctors and other experts, and published studies in peer-reviewed journals. We believe you should always know the source of the information you're seeing. Learn more about our editorial and medical review policies.

Hijazi ZR, East CE. 2009. Factors affecting maternal perception of fetal movement. Obstet Gynecol Surv 64(7):489-97

Hill MA. 2019. Fetal development. University of New South Wales Embryology. embryology.med.unsw.edu.auOpens a new window [Accessed November 2019]

Hoath SB, Mauro T. 2015. Fetal skin development. In: Eichenfield LF, Frieden IJ, Mathes E, et al. Eds. Neonatal and infant dermatology. 3rd ed. London: Elsevier: 1-13

Moore KL, Persaud TVN, Torchia MG. 2019a. Fetal period: ninth week to birth. Chapter 6 in The developing human: clinically oriented embryology. 11th ed. Elsevier

Moore KL, Persaud TVN, Torchia MG. 2019b. The placenta and fetal membranes. Chapter 7 in The developing human: clinically oriented embryology. 11th ed. Elsevier

NHS. 2018. You and your baby at 21 weeks pregnant. NHS, Health A-Z, Pregnancy and baby. www.nhs.ukOpens a new window. [Accessed November 2019]

RCOG. 2019. Information for you: your baby's movements in pregnancy. Royal College of Obstetricians and Gynaecologists. www.rcog.org.ukOpens a new window [Accessed November 2019]

Sato M, Kanenishi K, Hanaoka U, et al. 2014. 4D ultrasound study of fetal facial expressions at 20-24 weeks of gestation. Int J Gynaecol Obstet 126(3):275-9

Visembryo. 2014a. 18 weeks post fertilization: brown fat surrounds the lymphatic system. The Visible Embryo. www.visembryo.comOpens a new window [Accessed November 2019]

Visembryo. 2014b. 20 weeks post ovulation: bone marrow starts making blood cells. The Visible Embryo. www.visembryo.comOpens a new window [Accessed November 2019]