40 weeks pregnant: baby is the size of a small pumpkin

Your baby this week

Your baby is ready. The lungs, heart, brain and digestive system are mature enough for life outside. The skin has a thin layer of vernix in places and may be soft and pink. The skull bones are not fused, so the head can mould through the birth canal. Your baby's kidneys, liver and immune system are working.

Your baby's brain will keep growing rapidly through the first years of life.

How it happens. Your baby will be born when the hormonal signals between you and your baby, and the stretching of the uterus, tip into labour. Scientists do not fully understand the trigger, which is why the timing is unpredictable.

Your body this week

Your cervix may be soft and partly open, and you may feel pressure and cramps. Or you may feel nothing unusual. Both are normal. It is natural to be tired, excited and impatient. Rest, eat well and stay close to your maternity unit.

What the due date means

Your estimated due date is a calculation based on your last period or a dating scan. It is 40 weeks from the first day of your last menstrual period. It is a guide, not a deadline. Only about 1 in 20 babies is born on that day. Most arrive between 37 and 42 weeks.

If you are past 40 weeks, it does not mean anything is wrong. Your dates may be a few days off, and some babies take longer.

If you go past your due date

Your team will keep checking on you and your baby. Guidance differs by country, but it commonly includes:

• A membrane sweep. Offered from about 40 weeks in a first pregnancy, and 41 in later ones.
• Extra monitoring. Checks of your baby's movement and heartbeat, and sometimes a scan of the amniotic fluid.
• A discussion about induction. Usually around 41 to 42 weeks, since the risks to the baby slowly increase the longer pregnancy continues. You can ask about the risks and benefits, and your options, including waiting with monitoring.

Keep counting your baby's movements, and call if they change. See week 39 for how induction works.

The first hour after birth

Most newborns are placed on your chest right after birth, skin to skin, and covered with a warm blanket. This helps your baby stay warm and steady and helps you both to bond. Many babies will begin to root and feed in the first hour.

Your team will dry your baby, check breathing and colour, and may give a score for how they are doing at one and five minutes. The cord is clamped and cut, and you may want to discuss when in your birth plan. The placenta is delivered, and your baby may be weighed and measured, and offered vitamin K, after skin-to-skin contact if you prefer.

A newborn may look different from what you expect. Common and normal features include a cone-shaped or moulded head, puffy eyelids, blotchy or bluish hands and feet, a waxy white coating, tiny white spots on the nose (milia), fine hair on the shoulders and back, and dry, peeling skin in the first days. Newborn genitals and breasts may look swollen because of your hormones. Ask if you are unsure about anything.

Planning for the first weeks

You have done a great deal of preparing for the birth. It also helps to prepare for what follows.

• Bleeding. Expect vaginal bleeding, called lochia, for up to four to six weeks. It starts heavy and gets lighter.
• Pain and healing. Soreness from a tear, stitches or a cesarean wound is common. Ask about pain relief and wound care.
• Sleep. Newborns wake often. Sleep when you can, and accept help.
• Feeding. Ask for support early if feeding is hard. See week 34.
• Mood. Many people feel weepy, anxious or overwhelmed in the first two weeks. This is common and is often called the baby blues. If low mood, anxiety or intrusive thoughts last longer than two weeks or are severe, tell your provider. Postpartum depression and anxiety are treatable. See week 9 for signs and where to find help.
• Follow-up. You will usually have a check-up in the first days and again at about six weeks. Ask about contraception and pelvic floor recovery.
• Support. Line up meals, help with chores and someone you can call.

When to get urgent help after birth

Seek urgent care for any of these in the weeks after birth:

• Bleeding that soaks a pad in an hour, or large clots
• A fever of 38 °C (100.4 °F) or higher, or foul-smelling discharge
• A severe headache, changes in vision or sudden swelling
• Chest pain or trouble breathing
• Pain, redness or swelling in one leg
• A wound that is opening or leaking, or is red and hot
• Thoughts of harming yourself or your baby. Call your emergency number or a crisis line: 988 in Canada and the US, or Samaritans on 116 123 in the UK.

You know your body best. If something feels wrong, say so.