What's happening with your baby at 40 weeks
Your baby is considered full term and fully developed, typically measuring around 51 cm (20 in) and weighing somewhere between 2.9 and 4.0 kg (roughly 6.5 to 8.75 lb) — the range is wide and healthy. Most of the vernix (the waxy coating) and lanugo (fine body hair) have shed, though some babies are born with patches of both.
The lungs have been maturing for weeks and are ready for that first breath, though the final maturity of some systems continues after birth. The skull bones stay slightly separate and flexible, which lets baby's head mold a little during delivery.
Baby isn't 'done growing' — they'll keep adding fat right up until labor starts. Movement may feel different now simply because there's very little room left, but you should still feel regular activity every day.
Common symptoms at 40 weeks
Pelvic pressure, heaviness, and an increased urge to urinate are all common as baby settles deeper into the pelvis. Braxton Hicks contractions often become stronger and more frequent, and some people notice a 'bloody show' — a small amount of blood-tinged mucus as the cervix begins to change.
It's just as common to feel nothing different at all. Reaching 40 weeks with no signs of labor is normal and doesn't mean anything is wrong.
Exhaustion, trouble sleeping, and a mix of impatience and anxiety are all typical this week. Waiting for labor to start is genuinely one of the harder parts of pregnancy — there's no way to speed it along, and that's frustrating.
What if my due date passes?
Passing your due date is common — only around 4–5% of babies are born on the exact date, and many pregnancies extend into what's called the 41st or 42nd week. Your provider will likely start closer monitoring around now, such as non-stress tests or ultrasounds to check fluid levels and baby's wellbeing.
Most providers discuss induction if labor hasn't started by 41 to 42 weeks, in line with current ACOG guidance, though the exact timing depends on your health history and how the pregnancy is going. Going past your due date on its own isn't an emergency, but it does mean more frequent check-ins.
What to do this week
Keep your prenatal appointments — they'll be more frequent now and are how your provider tracks baby's wellbeing while you wait. Keep doing kick counts and pay attention to your baby's usual pattern of movement.
Rest when you can, but light activity like walking is fine and comfortable for most people. There's no proven way to bring on labor safely at home, so check with your provider before trying anything — including supplements or remedies you've read about online.
Make sure your hospital bag, car seat, and route to the hospital are all sorted if they aren't already. Have your provider's number and hospital admissions info somewhere easy to find.
Signs labor may be starting
True labor contractions become regular, get closer together over time, and grow more intense — unlike Braxton Hicks, they don't ease off with rest or a change of position. Losing the mucus plug or noticing a bloody show can happen hours to days before labor, or right at the start of it.
Your water breaking — a gush or a slow trickle of fluid — can happen before or during labor, and it's a reason to call your provider regardless of whether contractions have started. Lower back pain that comes in waves, along with pelvic pressure, is another common early sign.
When to call your provider
Call if you notice reduced fetal movement, any vaginal bleeding (more than light spotting), fluid leaking, or contractions that are regular and increasing in intensity — many providers use a '5-1-1' rule (contractions 5 minutes apart, lasting 1 minute, for 1 hour) as a general guide for when to head in, but follow your specific instructions.
Also call for a fever, a severe headache with vision changes, or sudden swelling in your face or hands — these can be signs of a blood pressure issue that needs same-day evaluation. When in doubt, call. It's what your provider is there for.