Week 37
Your baby is about 47.4 cm (18.7 in) long and weighs around 2.6 kg (5.7 lb), though babies vary a lot by now. The lungs are almost mature, and your baby is practising breathing movements, sucking and swallowing. Fat is filling out the cheeks, arms and legs, and the soft lanugo hair is mostly gone.
You may feel heavy, slow and ready. At the end of this week you reach 37 weeks, the start of early term. This is the week to learn how labour usually begins: the signs, the mucus plug, what happens if your waters break, and when to call or go in. A short preview of the stages of labour closes the week. The full story is in the labour and birth chapter.
Day 253 · 36 weeks 0 days
"Term" is not a single day
You may hear people say a baby is "full term" at 37 weeks. Doctors and midwives now use more precise words, because babies born a week or two apart can do quite differently.
Here is how the terms are usually defined:
Early term: 37 weeks 0 days to 38 weeks 6 days.
Full term: 39 weeks 0 days to 40 weeks 6 days.
Late term: 41 weeks 0 days to 41 weeks 6 days.
Post-term: 42 weeks and beyond.
Today, at 36 weeks, your baby is still called late preterm. Babies born now usually do well, but some need a little help with breathing, feeding, keeping warm or jaundice.
In early term, babies are ready to be born and most are healthy. Even so, the brain, lungs and liver keep maturing right up to 39 weeks. That is why most care providers do not plan an induction or caesarean before 39 weeks unless there is a medical reason.
None of this means you need to worry if labour starts on its own at 37 or 38 weeks. It simply means there is no rush. If labour starts before 37 weeks, call your care provider straight away.
Try this: Count forward on a calendar and mark the day you reach 37 weeks and the day you reach 39 weeks.
Day 254 · 36 weeks 1 day
Labour usually announces itself slowly
Few labours begin the way they do in films, with a sudden gush and a dash to the car. More often, the signs build over hours or days. Knowing them can help you tell the real thing from a false start.
The most common early sign is contractions that come regularly and get longer, stronger and closer together. You may also have a low, dull backache, or period-like cramps and pressure low in your pelvis. Some people have a "show", when the mucus plug comes away, often streaked with a little blood. Your waters may break, as a gush or a slow trickle. Loose bowels or an upset stomach are common too.
Some people also feel restless, emotional, or suddenly full of energy. Others feel nothing special until contractions are well under way. The single most reliable sign is a pattern of contractions that keeps building. Tightenings that come and go with no pattern, or fade when you rest, are more likely Braxton Hicks, which you read about in the second trimester. The next few days look at each sign in turn.
Try this: Save your care provider's or birth unit's phone number in your phone under "Labour" so you can find it fast.
Day 255 · 36 weeks 2 days
How to time your contractions
When tightenings start, timing them tells you whether they are building into labour. You need two things: how long each one lasts, and how often they come.
Time from the start of one contraction to the start of the next. That is the frequency. Then note how long each one lasts from beginning to end. A phone app or a pen and paper both work. Time a few in a row rather than just one.
True labour contractions come at regular intervals that get shorter over time. Each one lasts longer, often 45 to 60 seconds or more. They grow stronger, so you have to stop and breathe through them. And they keep going whether you walk, rest or change position.
Practice contractions, by contrast, are usually irregular, do not get stronger, and often ease off with rest, a warm bath or a drink of water. In early labour, there is no need to time every single one. Time a few, then rest, eat something light, and check again in an hour. Constant clock-watching can wear you out before labour has really begun. For your partner: Learn to time contractions now. When the day comes, you can keep the notes so the person in labour can focus on breathing.
Day 256 · 36 weeks 3 days
The mucus plug is a sign, not a starting gun
During pregnancy, a thick plug of mucus seals the opening of your cervix. It helps keep infection out. As the cervix starts to soften and open, the plug can come away.
You might see it as a blob of jelly-like mucus on the toilet paper or in your underwear. It may come out all at once or in pieces over several days. It can be clear, white, yellowish or pink, and it is often streaked with a little brown or red blood. That is called a "show". Some people never notice theirs.
Losing the plug means your body is preparing. Labour could start within hours, but it could also be days or even a couple of weeks away. On its own, it is not a reason to go in. Your body keeps making mucus, so a plug can partly re-form.
A little blood-streaked mucus is normal. Bright red bleeding is different. Get help right away if you have bleeding like a period or heavier, or bleeding with constant belly pain. Call your care provider or go to the birth unit. If you lose your plug before 37 weeks, call your care provider the same day.
Try this: Keep a panty liner in your bag and at your bedside so you can see the colour of anything you lose.
Day 257 · 36 weeks 4 days
If your waters break, notice four things and call
Your baby has been floating in amniotic fluid inside a sac of membranes. When the sac breaks, the fluid leaks out. This is called your waters breaking, or rupture of the membranes.
It may be a dramatic gush, but it is often a slow trickle that is easy to confuse with pee or discharge. Amniotic fluid is usually clear or pale straw-coloured and has a mild, slightly sweet smell. It keeps leaking, especially when you stand up or move.
For most people, the waters break during labour. For about 1 in 10, they break before contractions begin. Labour usually starts within a day of that, but your care provider will want to know, because the protective seal is gone.
If you think your waters have broken, put on a pad, not a tampon. Then note four things: the time, the colour, the smell, and how much there was. Call your care provider or birth unit, even if you have no contractions. They will tell you whether to come in now. Avoid sex and baths until you have spoken to them.
Get help right away if the fluid is green, brown or bloody, smells bad, you have a fever, your baby is moving less, or you feel something in your vagina.
Try this: Put a waterproof sheet or a folded towel under your bottom sheet, for peace of mind.
Day 258 · 36 weeks 5 days
Know when to call and when to go in
One of the most common worries is going in too early or too late. The best guide is the advice your own care provider gives you, so ask them now. Many care providers suggest that, in a first labour, you call when contractions come about every five minutes, last about a minute each, and have kept that pattern for about an hour. In a later labour, things can move faster, so you may be told to call sooner. You may also be told to call earlier if you live far away, had a fast labour before, are positive for Group B strep, or have a health condition.
Calling is not the same as going in. The midwife or nurse on the phone can talk you through what you are feeling and help you decide. You can call as many times as you need.
Get help right away if you have heavy bleeding, constant severe belly pain, your waters break and the fluid is green or brown, your baby is moving less than usual, you have a bad headache, vision changes or a seizure, or you feel an urge to push before you have reached the birth unit. Call your local emergency number if you cannot get to the birth unit safely. Try this: Ask at your next visit, "When exactly should I call you, and what number do I use at night?"
Day 259 · 36 weeks 6 days
A quick look at the stages of labour
Labour is usually described in three stages. Knowing the outline can make it feel less like a mystery. The full chapter on labour and birth goes into each one in detail.
The first stage is when the cervix thins and opens to about 10 cm. It starts with the early, or latent, phase. Contractions are often irregular and the cervix opens slowly. This phase can last many hours, especially in a first labour, and is usually best spent at home. Then comes active labour, when contractions become strong and regular and the cervix opens more quickly. The second stage begins when the cervix is fully open and ends with the birth of your baby. This is when you push, often with a strong, natural urge. It can take minutes or a few hours.
The third stage is the birth of the placenta, usually within an hour after your baby is born. You can choose to have an injection to speed this up and lower the risk of heavy bleeding, or wait for it to come on its own. Your care provider will talk through these options with you.
Try this: Ask your partner or support person to read this entry too, so you share the same picture of what lies ahead.