39th week: The downy hair is almost gone

Weeks and days
38+0 to 38+6
Month
10
Trimester
3

This week, the fetus gains from about 3,190 to 3,400 grams. The fine downy hair has almost disappeared, and the first stool collects in the bowel. Babies born now do not have breathing problems more often than at the due date.

Side view of a round baby bump in the 39th week of pregnancy, the hands resting beneath the bump, warm window light
around 3.4 kghow heavy your baby is at the end of the week

Week 39 of 40

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How big and how heavy is the fetus?

050100150200250300350400 mm37th week318 to 32738th week327 to 33639th week336 to 34440th week344 to 352

336 to 344 mm

By the end of the week, the fetus weighs about 3,400 grams. From head to heel, it measures about 48 centimeters.

Crown-rump length according to the values from Archie et al. 2006, weight according to the WHO growth charts.

This week

Your baby

  • The fine downy hair from the 2nd trimester is almost gone. Some babies are born with a few patches of it.
  • Thick, green stool, called meconium, collects in the bowel. It consists of everything the baby has swallowed, including amniotic fluid and hairs. Normally, it only comes out after the birth.
  • The baby now alternates between four clearly distinguishable states of sleep and wakefulness.

Your body

  • Many now feel impatient or bored.
  • At the prenatal checkup, your belly, blood pressure, and urine are checked. Protein in the urine can indicate preeclampsia. It can also occur after the birth.
  • With a normal weight before pregnancy, a gain of about 10.5 to 12.0 kilograms up to 39+0 is usual.

What matters now

  • At your prenatal checkup, talk about what happens if the baby keeps you waiting past the due date. The guideline for Germany, Austria, and Switzerland provides for information about your personal risks, such as age, smoking, severe overweight, and the baby's estimated weight.
  • Have your due date checked. It is compared with the measurement from the early ultrasound and corrected from a difference of 7 days, in Switzerland from as little as 5 days.
  • Keep your hospital bag and documents ready. The person accompanying you should be reachable at all times from now on.

Get checked right away: bleeding from the vagina, greenish or foul-smelling amniotic fluid, fewer baby movements than usual, a contraction that lasts longer than 2 minutes, severe headache, or vision problems.

Gestational sacPlacentaFetus with heartbeat

On ultrasound

  1. 38+0

    Head circumference is on average about 332 mm.

  2. 38+0

    Abdominal circumference measures on average about 338 mm.

  3. 38+0

    Thigh bone (femur) measures on average about 72 mm.

In Germany, Austria, and Switzerland, no further routine ultrasound is scheduled.

Frequently asked questions about the 39th week of pregnancy

How likely is a birth in the 39th week of pregnancy?

A birth is now possible at any time. In a study from Australia, about 2 out of 3 babies were born within 7 days before or after the calculated due date.

The mucus plug has come away. How much longer will it be?

That cannot be said exactly. The cervix is beginning to open. The birth may follow quickly or take a few more days. If you lose more blood, call the hospital or your midwife right away.

What do real contractions feel like?

Over time, they get longer, and the breaks between them get shorter. They are painful and pull into the back, the sacrum, and the lower abdomen. Some describe them as very strong period pain.

Can I have an induction on request in the 39th week of pregnancy?

This week, labor is only induced for medical reasons. At your express request, an induction can be considered from the 40th week of pregnancy.

Sources

Updated on 31 October 2026 · Fertilio Editorial Team