At 37 weeks your baby is about 47.5 cm and 2.9 kg — roughly a stalk of Swiss chard — and is now officially considered early-term, with lungs and organs ready for independent life.
The short answer: starting this week, baby is early-term, meaning the lungs and organs are ready for life outside if birth happens now. The sucking reflex is being actively practised by sucking on a thumb, and most lanugo hair has disappeared while the protective vernix coating remains. For you, the belly may have dropped even lower, sharp pelvic pains can happen as the head presses on nerves, and the mucus plug may pass as the cervix prepares.
Your baby this week
Starting this week, baby is considered early-term — a real milestone meaning the lungs and major organs are ready for independent life if born now. Baby is actively practising the sucking reflex by sucking their thumb, genuine preparation for feeding right after birth. Most of the fine lanugo hair that covered the body is gone, though baby is still coated in the protective, waxy vernix that helps ease the passage through the birth canal.
Weight is now around 2.9 kg, with steady gains continuing right up to birth.
Your body this week
Your belly may have dropped even lower now, easing breathing further but increasing pressure on the pelvis and bladder. Brief, sharp "shooting" pains in the pelvis are common — that's baby's head pressing on nerve endings, startling but not dangerous, and usually gone within seconds.
You may also notice the mucus plug passing — a thick discharge, sometimes with streaks of blood, that has sealed the cervix throughout pregnancy. It signals the cervix is starting to prepare, but does not predict exactly when labour will begin; it can happen days or weeks before, or go unnoticed entirely.
Tests and appointments
Appointments are typically weekly from here through the rest of the pregnancy for most care pathways.
✅ Worth doing this week
- Keep your documents with you at all times — passport, insurance, and maternity notes, even for a quick trip out
- Rest whenever you get the chance — labour takes real energy, and a daytime nap helps if night-time positions are uncomfortable
- Learn the difference between the mucus plug passing and heavier bleeding that needs a call
- Keep counting movements daily even as the pattern continues to change
- Confirm who will drive you to the hospital and have a backup plan ready
When to call your doctor
Call the same day if: bleeding is heavier than light streaking, contractions become regular and increasingly close together, your water breaks, or movement feels reduced or different from baby's usual pattern. Also call for a severe headache with visual disturbance, sudden swelling of the face or hands, or a temperature above 38°C.
FAQ — 37 weeks pregnant
What does "early-term" actually mean for the baby?
Early-term, medically defined as 37 weeks 0 days through 38 weeks 6 days, means that if baby is born now, the lungs and other major organs are considered ready for independent life outside the womb. It is a genuine milestone, though babies born in the full-term window (39 to 40 weeks 6 days) still show, on average, slightly better outcomes for lung and brain maturity — one reason care providers avoid inducing labour without a medical reason before 39 weeks where it can safely wait.
What does losing the mucus plug mean?
The mucus plug is a thick discharge, sometimes streaked with blood, that has sealed the cervix throughout pregnancy. Its passage is a sign the cervix is starting to soften and prepare, but it does not predict exactly when labour will start — it can happen days or even weeks before labour begins, or sometimes not be noticed at all. It is not, on its own, a reason to call your care provider unless the bleeding is heavier than light streaking.
What causes sudden shooting pains in the pelvis at 37 weeks?
Often called "lightning crotch," these brief, sharp pains happen when baby's head presses on nerve endings deep in the pelvis, especially as baby settles lower in preparation for birth. They are startling but not dangerous, usually pass within seconds, and become more common the closer you get to labour.
How big is the baby at 37 weeks?
About 47.5 cm and 2.9 kg — roughly a stalk of Swiss chard. Baby is actively practising the sucking reflex by sucking their thumb, most of the fine lanugo hair has disappeared, and the protective vernix coating remains to ease the passage through the birth canal.
Week 37 at a glance
At 37 weeks your baby is about 47.5 cm and 2.9 kg, officially early-term with lungs and organs ready for independent life, practising the sucking reflex, and coated in protective vernix. For you, the belly may have dropped further, sharp pelvic pains are common, and the mucus plug may pass as the cervix prepares — all typical signs of the body getting ready.
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