31 weeks pregnant

How big is your baby at 31 weeks?

About the size and weight of a coconut — around 41.1 cm (16.2 in) long head to heel, according to the NHS, weighing roughly 1,707 g (3 lb 12 oz).

In a couple of weeks both of you go through a final growth spurt.

A note on the numbers: from week 20 the NHS measures head to heel, not head to bottom. Weights here are the median of the WHO fetal growth charts — half of babies weigh more, half less, and a scan estimate can be out by 10 to 15 per cent either way. A number below the median is not a diagnosis.

What's developing this week

Your baby is busy: moving, sucking their fingers, and turning the occasional somersault. Day by day they look plumper and less wrinkled. There is more amniotic fluid around them now because they are producing more urine.

Voices from outside the womb are starting to be recognised. The NHS suggests encouraging your partner and any other children to talk to your bump — not because it accelerates anything, but because familiar voices at birth are genuinely calming.

What you might feel

You may feel your baby move down and see your bump shift lower. Some babies settle head down well before labour; others do not engage until labour starts.

Rib pain, breathlessness, heartburn, backache and pelvic pressure are all standard now. Braxton Hicks tightenings may begin. Persistent, regular or painful tightenings are a different matter — see below.

There is no target number of movements: the NHS is explicit that you do not need to count kicks. What matters is your baby's usual pattern, and calling immediately if it reduces, weakens or changes. Our kick counter describes a pattern; it does not score one.

Movements typically increase up to about 32 weeks and then stay roughly the same. If yours seem to be tailing off before then, that is a reason to call, not to wait.

Is 31 weeks pregnant 7 months or 8 months?

Week 31 is the last week of month 7. Month 8 starts next week.

There is no official weeks-to-months map. A calendar month averages about 4.3 weeks, not 4, so 40 weeks is a little over nine months, and two apps can disagree. The most widely used mapping:

• Month 1 — weeks 1 to 4
• Month 2 — weeks 5 to 8
• Month 3 — weeks 9 to 13
• Month 4 — weeks 14 to 17
• Month 5 — weeks 18 to 22
• Month 6 — weeks 23 to 27
• Month 7 — weeks 28 to 31
• Month 8 — weeks 32 to 35
• Month 9 — weeks 36 to 40

Your maternity team will not use months. Everything is booked by week and day — "31 weeks and 3 days" — because a few days change what is offered.

What's happening at your appointments around now

If this is your first baby, the NHS offers an appointment at 31 weeks: blood pressure, urine, bump measurement, a conversation about your baby's movements and your mental health, screening results, and preparing for birth — including how to know when you are in labour. If you have given birth before, your next appointment is at 34 weeks.

Which way up is your baby?

Around now your midwife or doctor will feel your bump to work out your baby's position, alongside measuring from your pubic bone to the top of your uterus to estimate size. RANZCOG asks for that fundal height measurement at every visit in Australia and New Zealand, plotted on a customised growth chart.

Plenty of babies are still head up at 31 weeks and there is time. If your baby is still breech at around 36 weeks, your team may offer ways to encourage them to turn. If a baby is in an awkward position, or the placenta is blocking the way down, a caesarean may be recommended — and the NHS is clear that you should be able to discuss the risks and benefits before you decide anything.

A bump measuring smaller or larger than expected usually leads to a growth scan. That is a check, not a diagnosis.

Is it safe to fly at 31 weeks pregnant?

In a straightforward pregnancy the medical position is unchanged: the RCOG says occasional air travel is not harmful, with no evidence that cabin pressure or humidity harm you or your baby. But you are well past ACOG's recommended 14 to 28 week window, and if you are carrying twins you are within a week of the point the RCOG names as the safest limit.

Keep two things apart. The medical position is the RCOG's: the safest time to fly is before 37 weeks with one baby and before 32 weeks with uncomplicated twins, because from those points labour becomes likely. The airline position is a commercial rule — most carriers refuse you after 37 weeks, some set an earlier limit, and from 28 weeks most want a letter from your midwife or doctor, which the NHS warns can cost money and take weeks. An airline rule is not medical advice.

The risk that is real: blood clots

ACOG puts it plainly: any travel of four hours or more — car, train, bus or plane — doubles DVT risk, and pregnancy adds to that. Under four hours the RCOG says you are unlikely to need special measures. Over four hours:

• Loose clothing, an aisle seat, regular walks about the cabin
• In-seat exercises roughly every 30 minutes, and water steadily
• Graduated compression stockings sized for you by a midwife or doctor — ACOG warns that stockings which are too tight or worn wrongly increase the risk instead

Practical points

• With twins, 32 weeks is the RCOG's medical limit and most airlines' commercial one. If a trip is planned beyond that, it needs rethinking now.
• Check what maternity and neonatal care exists at your destination, and carry your maternity notes.
• Tell your insurer you are pregnant. The NHS says cover should include care in labour, premature birth and the cost of changing your return date.
• Travel to Zika areas is not recommended; some travel vaccines and anti-malarials are unsuitable.

When to call your midwife or doctor

Maternity units are staffed 24 hours a day, and away from home you can walk into any of them.

Get emergency help now

Call your local emergency number (999 in the UK and Ireland, 911 in the US and Canada, 000 in Australia, 111 in New Zealand) or go to an emergency department if you have:

• Heavy vaginal bleeding, or bleeding with severe abdominal pain
• Abdominal pain you cannot concentrate through
• Fainting or collapse, chest pain, or sudden breathlessness
• A severe headache painkillers do not touch, blurred vision or flashing lights, pain below your ribs, vomiting, or sudden swelling of your face, hands or feet — NHS and ACOG both list these as pre-eclampsia symptoms needing immediate assessment
• Pain, swelling or heat in one calf or thigh, which can be a DVT

Call your midwife or maternity unit today, whatever the hour

• Any reduction, weakening or change in your baby's usual pattern of movements. Call immediately, not in the morning, and do not use a home doppler — hearing a heartbeat does not mean your baby is well
• Regular tightenings, period-type pains, or backache that is not usual for you — the NHS list for possible premature labour, meaning labour before 37 weeks, which affects about 8 in every 100 babies
• A gush or a trickle of fluid, which could be your waters breaking
• Any vaginal bleeding, however light
• Itching without a rash, especially at night or on your palms and soles — it can be intrahepatic cholestasis of pregnancy
• A temperature, feeling generally unwell, or burning when you pee
• Regular or painful tightenings, or tightenings that come with backache and pelvic pressure

You do not need to be certain something is wrong. That is what the number is for.