Third trimester

38 weeks pregnant: what is happening this week

Week 38 of 42worked example

49.8 cm

Measured: head to heelabout the length of a stick of rhubarb
This week runs: Thu, Sep 17, 2026 to Wed, Sep 23, 2026
Days to the estimated due date: 21
Term window (37-42 weeks): Thu, Sep 17, 2026 to Thu, Oct 22, 2026

The NHS publishes this figure for week 38, about the length of a stick of rhubarb. It is an average from patient guidance rather than a measurement of any particular pregnancy, and the measurement basis changes at week 20 - see the note below the dates.

49.8 cm, and the lanugo that covered the body from around week 15 has mostly been shed, though patches sometimes remain at birth and are unremarkable when they do. Meconium is accumulating in the bowel: dark, sticky, and the contents of the first several nappies. There is an antenatal appointment this week covering bump size, blood pressure and urine, and it is usually the first at which what happens after 41 weeks is discussed. Frustration is the emotional note of this fortnight, and it is worth naming rather than talking anybody out of. Everything is ready, nothing is happening, and every message from every relative asks the same question. Braxton Hicks continue and are easy to over-read at this stage. It is genuinely difficult to sit in a state of complete readiness for an event that will not be scheduled, and the people who cope best with it are usually the ones who deliberately keep doing ordinary things rather than the ones who clear the diary entirely and wait.

Put your own dates on week 38

Your estimated due dateNothing you type here leaves your browser. Without a date the panel shows a worked example built from a last period of Thu, Jan 1, 2026.

Week 1 began: Thu, Jan 1, 2026
Week 38 begins: Thu, Sep 17, 2026
Week 38 ends: Wed, Sep 23, 2026
Estimated due date: Thu, Oct 8, 2026

Dates run on ACOG's 280-day convention, the same arithmetic as the due date calculator. Share this week with your dates: /pregnancy/week-38?s=d:2026-10-08

Everything you type here is computed in your browser. Nothing you enter is stored on a server, sent anywhere, or shared — there is no account and no health data to leak.

What the NHS describes this week

The NHS puts the baby at around 49.8 cm from head to heel this week.
The lanugo has mostly been shed, though some patches may remain at birth.
Meconium is accumulating in the bowel from swallowed amniotic fluid.

What happens around now

A 38-week antenatal appointment covers bump size, blood pressure and urine, and is normally where the options after 41 weeks are first discussed.

38-week antenatal appointment - bump measurement, blood pressure, urine, discussion of options past 41 weeks (NHS)

On the measurement. The NHS publishes a length for each week from 4 to 40. Up to week 19 it is measured head to bottom (crown to rump, the measurement a scan takes while the legs are curled). From week 20 it is measured head to heel, which is why the figure jumps from 15.3 cm at week 19 to 25.6 cm at week 20 - the baby did not grow 10 cm in a week, the ruler changed. The NHS states the change on its week 20 page.

Where week 38 comes from

NHS: week 38 of pregnancy
NHS, Week-by-week guide to pregnancy — the guide these weeks are built from

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