Pregnancy Guide

You and your baby at 37-40 weeks pregnant

Your baby's development 

At 37 weeks, your pregnancy is considered full-term.  The average baby weighs around 3-4kg by now.

The baby's gut (digestive system) now contains meconium – the sticky, green substance that will form your baby's first poo after birth. It may include bits of the lanugo (fine hair) that covered your baby earlier in pregnancy.

If your baby does a poo during labour, which can sometimes happen, the amniotic fluid will contain meconium. If this is the case, your midwife will want to monitor your baby closely as it could mean he or she is stressed.

In the last weeks, some time before birth, the baby's head should move down into your pelvis. When your baby's head moves down like this, it is said to be 'engaged'. When this happens, you may notice that your bump seems to move down a little. Sometimes the head doesn't engage until labour starts.

The lanugo that covered your baby's body is now almost all gone, although some babies may have small patches of it when they're born.

Due to the hormones in your body, the baby's genitals may look swollen when they're born, but they will soon settle down to their normal size.

Your baby is ready to be born, and you'll be meeting him or her some time in the next couple of weeks.

Your body at 37-40 weeks pregnant

When you are around 37 weeks pregnant, if it's your first pregnancy, you may feel more comfortable as your baby moves down ready to be born, although you will probably feel increased pressure in your lower abdomen. If it's not your first pregnancy, the baby may not move down until labour.

Most women will go into labour when they are 38 to 42 weeks pregnant. Your midwife or doctor should give you information about your options if you go to more than 41 weeks pregnant.

Call your hospital or midwife at any time if you have worries about your baby or about labour and birth.

Find out what to expect if your baby is overdue.

Get ready for labour

Signs that labour has started

What happens in labour - Find out how to tell if labour is starting, and what happens in each of the three stages of labour.

Pain relief during labour - Be prepared by learning about all ways you can relieve pain during labour so you can decide what's best for you.

Be ready for the birth

When to go to the hospital/birth centre and what to expect - Find out at what point during labour you should contact your antenatal team, and what to expect when you get there.

What your birth partner can do - Your birth partner, whether it's the baby's father or a friend or relative, can support you during labour and birth.

Common concerns abour birth

Breech birth - A breech birth is when a baby is born bottom first, which is more complicated than a head-first birth.

Caesarean section - A caesarean section is when you have surgery to deliver your baby.

Induction - Your maternity team may recommend that your labour be started artifically. This is called induction.

If you baby is born to soon

Premature labour - Labour that starts before 37 weeks is considered premature. If your baby is born early, he or she may need special care in hospital.

Special care for ill or premature babies - What to expect if your baby is born early, or is ill and needs to be cared for in a special care baby unit.

Warning signs during pregnancy

Vaginal bleeding - Bleeding from your vagina may be a sign of a serious problem, so seek help.

High blood pressure and pre-eclampsia - High blood pressure in pregnancy can be a sign of pre-eclampsia, which can be life-threatening if untreated.

Severe itching - Severe itching can be a sign of the rare liver disorder obstetric cholestasis.


Pregnancy week by week

Over 40 weeks pregnant


Last Updated: 19/04/2021 10:20:01
The information on this page has been adapted by NHS Wales from original content supplied by NHS UK NHS website