What is happening in week 21
Doctors count pregnancy weeks from the first day of your last period, so week 21 sits in the second trimester (week 14 to week 27). That is about 19 weeks to go until week 40, and about 4.8 months by a rough conversion. In week 21 the baby is about 26.7cm long and heavier than the placenta.
Your baby
The NHS guide gives about 26.7cm head to toe, like a carrot. The baby is now heavier than the placenta, fine lanugo hair helps keep it warm, and it can hear voices and noises from outside the womb. It is also practising sucking and breathing and is settling into waking and sleeping patterns.
Your body
Your centre of gravity has shifted and your joints are looser, so you may feel unsteady. Tiredness is common and napping can help. Piles, backache and heartburn may start.
This week’s to-do
- Eat plenty of fruit and vegetables; the NHS suggests 5 portions a day.
- Nap when you can and take care on stairs.
- Talk to your doctor if your scan raised any worries.
When to call
Call your doctor or hospital if you have any bleeding, or if you have a fall, even if you feel fine.
Chaitanya Hospital in Kadapa, near RTC Bus Stand, Simhapuri Colony, provides delivery and emergency care 24/7. Our antenatal check-ups team can answer questions about your own pregnancy.
Use the week-by-week guide to jump to your week, or the due date calculator to work out your dates. Timings for scans and tests come from NHS guidance in the UK and can differ from your doctor’s schedule, so always follow your own doctor’s advice. This page is educational and not a substitute for a doctor.
Sources
Text on this page is paraphrased from the sources above. Sizes are averages and vary between babies.