What week range counts as 'full term'?

39 weeks 0 days through 40 weeks 6 days, under the ACOG definition adopted in 2013. Before that, anything from 37 to 42 weeks was loosely lumped together as 'term,' which obscured real differences in newborn outcomes across that range.

Is 37 weeks considered full term?

No — 37w0d to 38w6d is classified as 'early term,' a distinct category from full term. Babies born early-term are not premature, but outcomes on average are slightly better at full term, which is why the more granular labels replaced the single 'term' bucket.

When is a pregnancy considered post-term?

At 42 weeks 0 days (294 days from LMP) or later. Pregnancies approaching this point are typically monitored more closely, and induction is commonly discussed once 41 weeks is reached, per ACOG guidance.

Does 'late-term' mean the same as 'post-term'?

No. Late-term is 41w0d–41w6d — still within normal range but past full term. Post-term specifically means 42w0d or beyond. The two are adjacent but distinct categories.

Guide

Full-term vs. post-term pregnancy: the week cutoffs

'Full term' isn't one week — it's a defined four-week window, with three other labels bracketing it on either side.

By Buğra SözeriPublished September 25, 2026

For decades, obstetric shorthand called anything from 37 to 42 weeks “term,” as if outcomes were uniform across that five-week span. They’re not, and in 2013 ACOG, together with the Society for Maternal-Fetal Medicine, replaced the single label with four narrower categories. If you’re tracking a due date and seeing these terms in appointments or apps, here’s exactly what each one means.

The four term categories

Label	Gestational age
Early term	37w0d – 38w6d
Full term	39w0d – 40w6d
Late term	41w0d – 41w6d
Post-term	42w0d and beyond

Notice that full term is a four-day-short-of-two-week window, not a single date. Your calculated due date (40 weeks from LMP, or the equivalent from a conception date) sits right in the middle of the full-term range, not at its edge — which is part of why delivery a week or so before or after the due date is still squarely “full term,” not early or late.

Why the finer categories exist

The reclassification wasn’t cosmetic. Research reviewed by ACOG found measurable differences in newborn respiratory and other outcomes between early-term and full-term deliveries, even though both fell inside the old, broader “term” bucket. Separating early-term from full-term gave clinicians a more precise way to describe (and, where relevant, avoid) elective delivery before 39 weeks without a medical reason.

The same logic applies at the far end: late-term and post-term pregnancies carry gradually increasing monitoring recommendations, which is easier to communicate with two distinct labels (41 weeks vs. 42+) than one vague “overdue” catch-all.

How this maps to your own due date

If your due date calculator result says you’re at 39 weeks 2 days, you’re full term. At 37 weeks 5 days, you’re early term — not preterm, but not yet full term either. These labels are purely descriptive of timing; they aren’t a diagnosis, and this guide is educational, not a substitute for guidance from your own prenatal care provider, who will factor in your specific pregnancy alongside the calendar math.

For the week ranges that define trimesters (a separate, three-part system from these four term labels), see what trimester am I in by week.

Frequently asked questions

What week range counts as 'full term'?: 39 weeks 0 days through 40 weeks 6 days, under the ACOG definition adopted in 2013. Before that, anything from 37 to 42 weeks was loosely lumped together as 'term,' which obscured real differences in newborn outcomes across that range.
Is 37 weeks considered full term?: No — 37w0d to 38w6d is classified as 'early term,' a distinct category from full term. Babies born early-term are not premature, but outcomes on average are slightly better at full term, which is why the more granular labels replaced the single 'term' bucket.
When is a pregnancy considered post-term?: At 42 weeks 0 days (294 days from LMP) or later. Pregnancies approaching this point are typically monitored more closely, and induction is commonly discussed once 41 weeks is reached, per ACOG guidance.
Does 'late-term' mean the same as 'post-term'?: No. Late-term is 41w0d–41w6d — still within normal range but past full term. Post-term specifically means 42w0d or beyond. The two are adjacent but distinct categories.

Sources & references

Authoritative references cited by this piece. Verified by Buğra Sözeri on the dates shown and re-checked at every deploy.

ACOG Committee Opinion 579 — Definition of Term Pregnancy — The source of the early-term / full-term / late-term / post-term week ranges used industry-wide(as of 2026-09-25)
CDC — Reproductive Health: During Pregnancy — CDC background on pregnancy timing and monitoring near and after the due date(as of 2026-09-25)