20 weeks pregnant means 20+0 to 20+6 weeks from the first day of your last period: about 4 months and 18 days, so you are in the 5th month. You are halfway through: the detailed (anomaly) scan happens around now and the top of your womb reaches the level of your belly button.
20 weeks pregnant (20+0 to 20+6 weeks) is about 4 months and 18 days from the first day of your last period. You are in the 5th month and halfway through your pregnancy.
The NHS says your baby is now around 25.6 cm long, approximately the size of a banana. From this week length is measured from head to heel; in earlier weeks it was measured from head to bottom because the legs are curled up and hard to see. This week's figure therefore cannot be compared directly with earlier weeks.
The baby is now covered in a white, greasy layer called vernix, which is thought to protect the skin from drying out in the amniotic fluid and to help during birth. Your baby is more active every day, kicking, punching, turning and sucking a thumb (NHS). ACOG's summary for weeks 17 to 20 says the digestive system is working and the ears, nose and lips can be recognised on ultrasound.
The top of the womb reaches the belly button at about 20 weeks; after 24 weeks the measurement in centimetres from the pubic bone roughly matches the number of weeks (UpToDate, 2026). The NHS says most pregnancy weight is usually gained after week 20.
You may be woken at night by sudden sharp pain in your calves: this is probably cramp. The NHS suggests rubbing the muscle hard or pulling your toes up towards your ankle, and exercising more during the day. The bubbling or fluttering you feel may be your baby moving.
Detailed scan: the NHS says the anomaly scan may be this week; the sonographer checks the baby's development and the placenta. The Turkish Ministry of Health guideline (2026) places this scan at 18 to 24 weeks, NICE at 18+0 to 20+6 weeks and ACOG at 18 to 22 weeks.
Second visit (Turkish Ministry of Health, 18 to 24 weeks): weight, blood pressure, height of the womb (referral if 4 cm larger or smaller than expected), urinalysis and blood count; whooping cough (Tdap) vaccine at 18 to 24 weeks (or until the end of week 32 if missed). Women not in a high-risk group are told about the 50 g glucose screening test due at 24 to 28 weeks. The NHS usually offers the whooping cough vaccine around week 20; the immunity passes to the baby through the placenta and protects the baby until their own routine whooping cough vaccination.
Blood pressure: under the Turkish Ministry of Health guideline, 140/90 mmHg or higher counts as high blood pressure in pregnancy; high readings are measured at least 2 times and need specialist referral; at 160/110 mmHg or higher the reading is repeated after 15 minutes and, if still high, treatment is started and the woman is transferred by ambulance (112). NICE recommends that a first reading of 140/90 mmHg or higher after 20+0 weeks is seen in hospital within 24 hours, and 160/110 mmHg or higher on the same day.
ACOG says this ultrasound looks for major structural problems in the brain and spine, face, abdomen, heart and limbs, and NICE also asks for the position of the placenta. UpToDate notes that ultrasound generally shows the sex at 17 to 20 weeks; the NHS reminds you that not every hospital's policy is to reveal it.
| Symptom | Usually | Seek care if |
|---|---|---|
| Night-time calf cramps | Common in the second half of pregnancy; rubbing the muscle and pulling the toes up helps (NHS; UpToDate). | Tell your doctor if cramps are frequent or severe; UpToDate notes that blood tests may then be done. |
| Not feeling movements yet | In a first pregnancy movements may not be felt until after 20 weeks (NHS); most mothers notice them at 16 to 20 weeks (UpToDate). | The Turkish Ministry of Health guideline treats no movements after 20 weeks as a reason for referral; the NHS says to tell your midwife if you have felt nothing by 24 weeks. |
| Headache | Headaches are a common pregnancy symptom (NHS). | A severe headache, or a headache that does not go away with one dose of paracetamol, changes in vision, or persistent pain under the ribs or in the upper right tummy can be signs of pre-eclampsia; get help without waiting (UpToDate; Turkish Ministry of Health). |
These are danger signs or emergency referral criteria in the Turkish Ministry of Health guideline; contact your doctor or go to the nearest emergency department without waiting. NICE recommends a hospital review for any unexplained bleeding after 13 weeks, and anti-D for women who are RhD negative and at risk of isoimmunisation. The NHS says to call immediately if your baby's movements change, without waiting until the next day, even in the middle of the night.
Days 140 to 146 from the first day of your last period, or about 4 months and 18 days. You are in the 5th month and halfway through your pregnancy.
According to the WHO fetal growth charts (2017), the median (50th percentile) estimated fetal weight at 20 weeks is 330 g, and the 10th to 90th percentile range is 286 to 380 g. These are reference values from ultrasound measurements in low-risk pregnancies in ten countries; the authors note differences between countries, with maternal factors and with fetal sex, and say the charts may need adjusting for local use. UpToDate adds that ultrasound weight estimates are generally not useful before about 24 weeks. The NHS gives a length of about 25.6 cm from head to heel.
Often yes: UpToDate notes that ultrasound generally shows the sex at 17 to 20 weeks. If you do not want to know, say so before the scan; the NHS points out that not every hospital's policy is to reveal it.
In a first pregnancy it is common not to feel movements until after 20 weeks (NHS). However, the Turkish Ministry of Health guideline lists feeling no movements at all after 20 weeks among reasons for specialist review, and the NHS says to tell your midwife if you have felt nothing by 24 weeks. Raise it at your next check.
On examination, the top of the womb reaches the belly button at about 20 weeks (UpToDate, 2026). The Turkish Ministry of Health guideline advises specialist referral if the height of the womb is 4 cm larger or smaller than expected for the week.
Last updated: . All sources have been confirmed with their latest versions. This content is for educational purposes and is not a substitute for a doctor's examination.