The Playbook

39 Weeks Pregnant: Full Term, Induction and Last Dates

By the Guide to Fatherhood editorial team. Last reviewed . 2 min read.

Checked against guidance from organizations like the AAP, CDC, ACOG and NHS (linked below). This is general information, not medical advice. Read our medical disclaimer.

Trimester3
Sizea mini watermelon
Length / weightabout 20 in (50.7 cm), about 7.3 lb (3.3 kg)

Full term. The baby is ready for life outside: the lungs are mature enough to breathe, and fat stores will help with temperature control after birth.

Your to-do list this week

  • Learn what induction involves, in case it's offered or recommended. Ask the provider about the reasons, timing, and what to expect.
  • Keep the contraction timer handy and the car ready.
  • Plan a last pre-baby date close to home: a favorite restaurant, a movie, a long walk.
  • Write a short letter to your kid. You'll want to remember who you were this week.
A conversation to have this week

"How do you feel about induction if it comes up?" Learn her thinking now, so you can ask good questions with her provider.

Full term

At 39 weeks, the baby is officially full term (ACOG), about seven pounds and roughly twenty inches long. The lungs are mature enough to breathe air, and fat stores will help keep the baby warm after birth (NHS).

How she may be feeling

Ready, uncomfortable, and tired of being asked. There may be false starts and a lot of “was that one?”

Induction: what dads should know

Her provider may raise inducing labor, starting it with medications or procedures instead of waiting. According to ACOG, reasons include medical conditions like high blood pressure or diabetes, the water breaking without labor starting, and the pregnancy going past the due date. In some situations, an elective induction at 39 weeks is an option after discussion with the provider.

Things that help to know:

  • It can take a while. If the cervix isn’t ready, the first step is ripening it, which can take many hours.
  • Pack for a longer stay and bring entertainment for the early phase.
  • Ask questions: Why now? What are the steps? What happens if it doesn’t progress?
  • It’s still labor. Comfort measures, advocacy, and snacks all still apply.

Stay ready without hovering

There’s a fine line between attentive and annoying. Check in, don’t interrogate. “How are you feeling?” once in the evening beats “Anything?” every hour. Keep the car fueled, bags by the door, and the contraction timer one tap away.

A small thing worth doing

Write a short letter to your kid: what life is like this week, what you’re excited about, what you’re nervous about. It takes fifteen minutes. In eighteen years, it’ll be priceless.

Frequently asked questions

Why would labor be induced?

Induction may be recommended for medical reasons, such as high blood pressure, gestational diabetes, the water breaking without labor starting, or going past the due date. In some cases, couples can choose an elective induction at 39 weeks after discussing the benefits and risks with their provider.

How long does an induction take?

It varies widely, from hours to a couple of days, especially if the cervix needs softening first. Pack for a longer stay and bring things to pass the time.

Sources

  1. Labor Induction, American College of Obstetricians and Gynecologists
  2. Definition of Term Pregnancy, ACOG
  3. Week 39: Your baby and your body, NHS

We link to the original source for every medical and safety claim. Guidance changes; if a source has been updated since our last review, the source wins. How we research.