Pregnancy Week 37: Full Term — What to Expect as Labour Approaches

8 min read

Quick answer: At 37 weeks your pregnancy is full term, so a baby born now is unlikely to need extra medical support. Your baby measures about 48.6cm and weighs around 2.9kg, with mature lungs. Watch for a show, waters breaking or regular strengthening contractions, and contact your maternity unit immediately if your waters break, you bleed, or your baby's movements change. Call 999 for heavy bleeding or if your baby is coming now.

What parents need to know

Week 37 is a significant milestone: your pregnancy is now considered full term. This means that if your baby is born this week, they're unlikely to need any extra medical support and are expected to thrive. The final weeks of pregnancy can feel like a waiting game, but your body and baby are still busy with important final preparations.

Stage	Full term
Length	Approximately 48.6cm crown to heel
Weight	Around 2.9 kilograms
Lungs	Considered mature and ready for breathing air

How big is your baby at 37 weeks?

Your baby now measures approximately 48.6cm from crown to heel and weighs around 2.9 kilograms, roughly the weight of a large bunch of leeks. They're nearly at their birth weight and length, though every baby is different and yours may be larger or smaller.

What's happening with your baby?

Now that your baby is full term, their lungs are considered mature and ready for breathing air. The brain and nervous system continue to develop rapidly — this process continues long after birth and well into childhood. Your baby is now spending a lot of time in quiet, restful states as they conserve energy for the birth and the demands of the newborn period. The head may be settling deeper into your pelvis if it hasn't already, which can create increased pressure on the bladder (leading to more frequent trips to the toilet) but a welcome sense of relief from the breathlessness of earlier weeks.

Close-up of a parent's hands gently cradling a newborn's foot, symbolizing care and tenderness.

Signs that labour is approaching

In the days or weeks before labour begins, you may notice several signs that your body is preparing. A 'show' — the passage of the mucus plug that has sealed the cervix during pregnancy — is a common early sign. It may come as a single lump or in smaller pieces and is often slightly blood-stained (this is normal). A show can precede labour by days or weeks. Your waters may break — this can be a dramatic gush or a slow trickle, and the fluid should be clear or slightly pinkish. If your waters break, call your midwife or maternity unit straight away. Tell them immediately if the waters are smelly or coloured, or you're losing blood, as this could mean you and your baby need urgent attention. Contractions that are regular, become progressively stronger, and come closer together over time are the clearest sign that labour has begun.

When to get help

Some symptoms in pregnancy can be a sign of something serious and need checking quickly. This is who to contact, and how soon.

Call 999 if:

you're bleeding from your vagina and the bleeding is heavy (soaking a period pad soon after putting it on), or you also have severe pain in your tummy, pain in your shoulder, or feel sick, faint, dizzy or lose consciousness
you think your baby is coming now and you have a strong urge to push (ask for an ambulance)
you have severe difficulty breathing (you're gasping, choking or not able to get words out) or your chest feels tight or heavy
you have pain and swelling in one leg and you also feel short of breath or have chest pain. A blood clot in the leg can travel to your lungs, which can be life-threatening
you have possible signs of sepsis, such as breathing very fast, being confused or having slurred speech, blue, pale or blotchy skin, a rash that does not fade when you press it, or a very high or very low temperature. Being pregnant makes sepsis more likely
you do not feel you can keep yourself safe (a mental health emergency is as serious as a physical one)

Always call 999 if you think it's a life-threatening emergency, no matter what stage of pregnancy you are.

Call your midwife or maternity unit now if:

your baby is moving less than usual, you cannot feel your baby moving anymore, or there is a change to your baby's usual pattern of movements
you have light bleeding or spotting, even if you have no pain or only mild tummy pain
you have stomach pain that is severe or does not go away after you've rested for 30 to 60 minutes, or stomach pain with regular cramping or tightenings, lower back pain, or pain when you pee
you're less than 37 weeks pregnant and you have a gush or trickle of fluid from your vagina (this could be your waters breaking), regular contractions or tightenings, period-type pains, or backache that's not usual for you
your waters break, even if labour has not started
you have signs of pre-eclampsia: a severe headache that does not go away with simple painkillers, vision problems (such as blurred vision or seeing flashing lights), pain below the ribs, sudden swelling of the face, hands or feet, feeling very unwell, heartburn that does not go away with heartburn medicines, or being sick (vomiting)
your skin is very itchy (for example, it keeps you awake at night), the palms of your hands or soles of your feet are itchy, or the itching is worse at night. This can be a sign of a liver condition called intrahepatic cholestasis of pregnancy (ICP) that needs urgent treatment
your breathlessness comes on suddenly, you're out of breath when you're lying down, or you're breathless and also have chest pain or feel dizzy
you have pain or swelling in one leg, usually in the calf or thigh. This could be a blood clot (deep vein thrombosis, or DVT), which is more likely when you're pregnant
you have a high temperature (38C or above), or you feel hotter than usual or shivery. A high temperature can be a sign of an infection, so it's important to get it checked
any of your contractions last longer than 2 minutes, or you're having 6 or more contractions every 10 minutes

If your baby's movements change, do not wait until the next day: call immediately, even if it's the middle of the night. Do not use a home doppler to check the heartbeat yourself. Even if you hear a heartbeat, this does not mean your baby is well.

If your waters break, use a period pad (not a tampon) so your midwife can check the colour of the waters, and tell them immediately if the waters are smelly or coloured.

Call your midwife or maternity unit for guidance if you think you're in labour, or you're having regular contractions coming every 5 minutes or more often.

You can also call your midwife or maternity unit if you're unsure or worried about anything.

If you cannot reach them, or you're not sure what to do, call NHS 111.

Speak to your midwife or GP if:

you're worried about your mental health, or stress, anxiety or low mood are affecting your day-to-day life. If you need urgent help for your mental health, call 111 and select the mental health option, or ask for an urgent GP appointment

Go to sleep on your side. From 28 weeks, the safest position to go to sleep is on your side, either left or right. Research suggests that, after 28 weeks, falling asleep on your back can double the risk of stillbirth. This includes daytime naps. If you wake up on your back, just turn onto your side and go back to sleep.

Preparing emotionally for birth

It's normal to feel anxious about labour and birth, particularly if it's your first baby. Talking to your midwife, attending antenatal classes, and speaking with other parents can all help. If anxiety is significant and affecting your daily life, speak to your GP or midwife, as support is available including cognitive behavioural therapy (CBT) and counselling.

Your week 37 checklist

This week:

Know the signs of labour and when to call your maternity unit.
Make sure your hospital bag is by the door.
Install the car seat.
Rest and eat well.
Share any birth anxieties with your midwife.

Sources & further reading

General information, not individual medical advice. Speak to your GP, midwife or health visitor about your baby’s needs.