40 weeks pregnant: symptoms and baby development
Due now. As ready as they’ll ever be.
Third trimesterMonth 95 min read
By Solesia, from public clinical guidanceUpdated
The date on the calendar has arrived, and it is worth saying plainly that only about one baby in twenty arrives on it. It is a due date, not an appointment. Your baby is as ready as they will ever be, and they keep to their usual rhythm of movement right up to birth. For you, the week is about telling the rehearsal from the real thing, and about patience, because going past the date is common and expected. If the week passes and nothing has happened, your provider will talk with you about what happens next, and that is an ordinary conversation.
How big is your baby at 40 weeks
About the size of a pumpkin
20.2 in long·7.6 lb
Baby development at 40 weeks
At 40 weeks your baby measures about 20.2 inches from head to heel and weighs around 7.6 pounds, roughly a pumpkin. Everything is complete: lungs ready to take a first breath, a gut ready for milk, fat enough to hold their temperature, and a store of your antibodies to see them through the first months.
The skull plates are still soft and separate, and they will overlap during birth so the head can pass through, which is why a newborn’s head can look a little pointed for a day or two before it rounds out. Their eyes are open and will focus on your face at about ten inches; their hearing knows your voice.
They move as much as they did last week and the week before. In tight quarters that means pushes, rolls and stretches rather than kicks, at the times of day you have come to expect. The rhythm holds through the due date and through labor itself; it is the pattern you know that tells you all is well.
Your body at 40 weeks
Practice contractions and the real thing can be hard to tell apart at first, and that is expected. Real contractions hurt, usually starting in the back or low in the bump and building as the tightening peaks, then easing as it relaxes. They get longer, stronger and closer together over an hour or more, and they do not stop if you walk, rest or take a bath. Practice ones stay irregular and fade.
Going past your date is common and expected, and it is nothing you have done. A due date is a best guess, with a normal range on either side; about half of first babies arrive after it. Your provider keeps the weekly visits going and may offer a membrane sweep now, extra monitoring after 41 weeks, and a date for induction if labor has not begun by then.
You are tired, sore and very ready, and that is expected too. Pelvic pressure, backache, swollen feet and broken sleep are all part of this week. Fill the days with small, easy things, eat well, and rest with your feet up. Every day now is the last one for a while when you can nap whenever you like.
Common pregnancy symptoms at 40 weeks
- Contractions, practice and real. Real ones hurt, build and come closer together. Time them for an hour before deciding.
- Pelvic pressure. The head low in the pelvis. Side lying, and a warm bath.
- Backache. Weight low and forward. Warmth, and let others lift.
- Impatience. The date came and the baby did not. Common, and not a sign of anything.
- Swollen feet. Fluid in the last days. Feet up, water, a slow walk.
- Broken sleep. Everything at once. Nap without guilt.
- Heartburn. Still a crowded stomach, if the baby has not dropped. Small meals, propped up in bed.
When to call your provider at 40 weeks
Movements should not slow down or stop, even now. If they do, call straight away.
Two things are worth a same-day call at any point in pregnancy: bleeding that is more than spotting, and pain that is severe or does not ease. From the second trimester, add fluid leaking and any change in your baby’s usual pattern of movement. You do not need to be sure something is wrong to call; that is what the number is for.
What to do at 40 weeks
- The due-date visit. Blood pressure, urine, bump and heartbeat, and a conversation about the next week: a membrane sweep now, what monitoring looks like after 41 weeks, and when induction would be offered.
- Time, do not guess. When contractions start, write down when each begins and how long it lasts. An hour of a minute-long contraction every five minutes is the usual point to call; ask your provider for their rule.
- Your baby’s pattern. Their movements keep to the rhythm you know, right through the due date. If they slow down or change, call straight away rather than waiting for the visit.
- Rest and eat. Light meals and plenty of water, sleep when you can, and a walk if you feel like one, the same advice as at 38 weeks and 39 weeks. Labor is work, and you want to start it fed and rested.
Common questions at 40 weeks
What happens if I go past my due date?
Weekly visits continue, and from 41 weeks your provider usually adds monitoring of the baby’s heartbeat and the fluid around them. A membrane sweep may be offered to nudge labor along. If labor has not started by about 41 to 42 weeks, induction is offered. About half of first babies arrive after their date, so this is a well-worn path.
How do I know if my water broke?
A gush, or a steady trickle you cannot control, of clear or pale fluid with little smell. If you are not sure, put on a pad and check in an hour: urine stops, amniotic fluid does not. Either way, call your provider, even without contractions, and mention the color; green or brown fluid is worth saying.
Can I do anything to start labor at 40 weeks?
Little has been shown to work, and nothing that is safe does harm. Walking, sex if your water has not broken, and nipple stimulation are the ones with some evidence behind them. A membrane sweep from your provider is the one with the best. Castor oil and herbal remedies are not recommended.
When should I go to the hospital?
The usual rule is contractions about a minute long, every five minutes, for an hour, or as soon as your water breaks, or if you have bright red bleeding. Your provider may give you a different rule if you live far away or had a fast labor before. When in doubt, call: the labor unit answers at any hour.
Written from public clinical guidance, including NHS: Week 40, ACOG: How your baby grows, ACOG: Changes in your body, NHS: Signs of labour, NHS: Your baby’s movements and ACOG: Bleeding. This page is general information, not medical advice, and does not replace your provider.