Week 37
Your baby is the size of a bunch of Swiss chard
You crossed an administrative line this week. Per ACOG Committee Opinion #579, your baby is now early term. That's 37 through 38 weeks. NICU admission rates run about 9.4% at 37 weeks versus 5.0% at 39 weeks per Laughon et al. (Am J Obstet Gynecol, 2014). Every extra day still matters. Here's what week 37 actually is, and why your provider isn't rushing.
Key takeaways
- Week 37 is the early term threshold per ACOG Committee Opinion #579 (reaffirmed 2025). Early term runs 37 through 38 weeks. Full term begins at 39.
- NICU admission rates run about 9.4% at 37 weeks vs 5.0% at 39 weeks per Laughon et al. (Am J Obstet Gynecol, 2014), based on 188,809 US singleton deliveries. Most stays are short. The absolute risk stays low.
- The 5-1-1 rule activates this week for low-risk pregnancies: contractions every 5 minutes, lasting 1 minute, for at least 1 hour. Per ACOG patient guidance, that is the typical signal to head in.
- Losing your mucus plug does not reliably predict when labor will start per ACOG. It can happen days or weeks before contractions begin.
What does 'early term' actually mean for your baby?
Per ACOG Committee Opinion #579 (reaffirmed 2025), early term is 37 weeks through 38 weeks of gestation. Full term begins at 39.
The old '37 weeks is term' framing got retired for a reason.
Per Laughon et al. (Am J Obstet Gynecol, 2014), in a cohort of 188,809 US singleton deliveries, NICU admission rates were 9.4% at 37 weeks, 5.8% at 38 weeks, and 5.0% at 39 weeks. Respiratory morbidity followed the same pattern.
Most early-term babies do beautifully. They breathe well, feed well, and go home with you. The rate difference is real. The absolute risk is low.
The grasp reflex is fully wired by now. Put your finger in their palm at birth and they'll hold on. So is rooting, sucking, and the Moro startle.
If your baby is head-down, the head may begin to settle deeper into your pelvis this week or in the next couple of weeks, especially if this is your first pregnancy. For repeat pregnancies, engagement often waits until labor.
A still-breech baby this week is the window for the conversation your provider mentioned at week 36. External cephalic version is offered at or after 37 weeks per current ACOG guidance.
Why the 5-1-1 rule starts mattering this week, and why your provider isn't pushing early delivery
Two thresholds shift at week 37.
The labor-call rule changes. Through week 36, four or more contractions in 20 minutes was the call-your-provider trigger. From 37 weeks on, the 5-1-1 rule kicks in for low-risk pregnancies: contractions every 5 minutes, lasting 1 minute, for at least 1 hour. That is the standard go-to-the-hospital signal. Confirm the exact threshold your practice uses.
The delivery-timing conversation also shifts.
Per ACOG Committee Opinion #765, a non-medically-indicated delivery before 39 weeks should be avoided in low-risk pregnancies. The brain gains substantial mass between weeks 37 and 39. Lung function keeps maturing. Feeding coordination strengthens.
If your pregnancy is healthy, your provider will steer toward spontaneous labor or, when induction is needed, schedule it for 39 weeks or later.
Weekly visits, which started around week 36, now include:
- Blood pressure, urine protein, fundal height, fetal heart rate
- A position check if your baby has been on the bubble
- A cervical check only if you request one. Most practices do not check routinely without a reason.
Sleep is broken. Walking is harder. Heartburn is constant. Feet swell.
You may notice losing your mucus plug. It can be clear, pink, or slightly blood-tinged ('bloody show'). Per ACOG, mucus plug loss does not reliably predict when labor will start. Days. Weeks. It varies.
Contact your provider right away if you have heavy bleeding, fluid leakage, severe headache or vision changes, upper-belly pain, or a sustained drop in your baby's movement.
For dads
Here's your move:
Take the day-of plan from theory to muscle memory this weekend. Drive the route to the hospital at the actual time of day she's most likely to be in labor, not the off-hours fantasy version. Save the L&D direct line in your phone, not the main hospital number. Park the bag in the car, with chargers and water. Have a friend on standby for the dog or the older kids. Walk through it in your head once a day until it's reflex. The first time you do it for real, you'll be running on adrenaline, sleep deprivation, and your partner staring at you. The pre-loaded version of you saves the panicked version of you a real cost.
Real talk:
She's been ready to be done for about three weeks. Three more weeks of this is unbearable to her on a Tuesday afternoon, and you can't fix that. Don't try. The phrase 'almost there' is a trap right now because 'almost' could be 17 more days. What works: bring her water without asking. Bring her food she didn't request but knows she likes. Take dinner planning off her plate. Don't narrate the niceness. Quiet competence outperforms cheerful narration. You've practiced this. The newborn shift is about to make it the rest of your life.
Common concerns
My baby barely moves around anymore. Should I worry?+
Big kicks become smaller pushes, stretches, and rolls as your baby fills the amniotic sac per Mayo Clinic. The style changes. The overall level of activity should not drop. Count 10 movements in two hours during your baby's active window. If you don't reach it, lie on your left side, drink something cold, and try again. Still short, call your provider. Decreased fetal movement late in pregnancy is always worth a call.
I lost my mucus plug. Does that mean labor is starting?+
Probably not imminently. Per ACOG, losing your mucus plug means your cervix is softening and beginning to dilate, but it does not predict when labor will start. Some people lose it weeks before labor. Others do not notice losing it at all. It can be clear, pink, or slightly blood-tinged ('bloody show'). Mention it at your next appointment, but do not head to the hospital unless you also have regular contractions or fluid leakage.
Can I do anything to start labor naturally at 37 weeks?+
Do not try yet, even if you can. Per ACOG Committee Opinion #765, non-medically-indicated delivery before 39 weeks should be avoided in low-risk pregnancies. Walking and gentle activity are fine and may help the baby descend, but they will not kick off labor if your body is not ready. Nipple stimulation can trigger contractions and should only be done under provider guidance. The safest play is to let your body run on its own clock.
When will my provider start talking about induction?+
For an uncomplicated pregnancy, most providers wait for spontaneous labor or schedule induction at 39 weeks or later, per ACOG. With risk factors like gestational diabetes, hypertension, low amniotic fluid, or others, your provider may recommend induction earlier. The decision is individualized. If you pass your due date, monitoring increases and induction is typically discussed between 41 and 42 weeks.
Product picks for week 37
As an Amazon Associate, Cradlebug earns from qualifying purchases — at no extra cost to you. Learn more
BABYGO Birthing Ball with Exercise Book Set
65cm anti-burst ball with a trimester-specific guide. The exact tool for the gentle activity that may help the baby descend.
Frida Mom 11pc Postpartum Essentials Kit
Hospital-bag postpartum bundle: disposable underwear, ice maxi pads, healing foam, peri bottle, pad liners. Ready for any-day delivery.
Galabloomer Maternity Labor Delivery Robe and Baby Swaddle Set
Lightweight robe that doubles as the going-home and first-photos outfit. Pairs with a matching baby swaddle.
Sources
- ACOG, Definition of Term Pregnancy (Committee Opinion No. 579, November 2013, reaffirmed 2025) — https://www.acog.org/clinical/clinical-guidance/committee-opinion/articles/2013/11/definition-of-term-pregnancy
- ACOG, Avoidance of Nonmedically Indicated Early-Term Deliveries and Associated Neonatal Morbidities (Committee Opinion No. 765, February 2019) — https://www.acog.org/clinical/clinical-guidance/committee-opinion/articles/2019/02/avoidance-of-nonmedically-indicated-early-term-deliveries-and-associated-neonatal-morbidities
- Laughon SK, Reddy UM, Sun L, Zhang J. Neonatal Outcomes in Early Term Birth. Am J Obstet Gynecol. 2014;211(3):265.e1-265.e11 — https://pmc.ncbi.nlm.nih.gov/articles/PMC4149822/
- ACOG, How to Tell When Labor Begins (patient FAQ) — https://www.acog.org/womens-health/faqs/how-to-tell-when-labor-begins
- ACOG, What does it mean to lose your mucus plug? — https://www.acog.org/womens-health/experts-and-stories/ask-acog/what-does-it-mean-to-lose-your-mucus-plug
A quick note: This content is for informational purposes only and is not a substitute for professional medical advice. Always talk to your healthcare provider about any questions or concerns. Content based on guidance from the American College of Obstetricians and Gynecologists (ACOG), the American Academy of Pediatrics (AAP), Mayo Clinic, and peer-reviewed medical literature. Learn how we create our content.