Quick answer: Week 40: Post-dates monitoring, induction methods, Bishop score, emotional toll of waiting.
Week 40 — you’re in the third trimester, the final stretch. Your baby is gaining weight rapidly, your body is working harder than ever, and the finish line is in sight. It’s completely normal to feel a mix of excitement, anxiety, and ‘let’s just get this done.’
Baby Development This Week
At week 40, your baby is approximately the size of a large pumpkin — measuring around 20.2 in / 51.2cm. Full term and ready. All systems go — baby could arrive any day. Growth and final organ maturation are the priorities now. Your baby gains approximately half a pound per week from week 28 onward, laying down the fat deposits that will regulate body temperature after birth.
Symptoms You May Feel
Third trimester week 40 commonly brings: shortness of breath as the uterus presses against the diaphragm (improves when baby drops lower, usually weeks 36–38 for first pregnancies), heartburn at its peak as the stomach is compressed, frequent urination returning with a vengeance, swollen ankles and feet from fluid retention and venous compression, pelvic pressure and occasional ‘lightning crotch’ (sharp nerve pain), Braxton Hicks becoming more frequent and sometimes intense, carpal tunnel syndrome from fluid pressing on wrist nerves, and sleep disruption from physical discomfort and frequent waking.
Post-dates monitoring, induction methods, Bishop score, emotional toll of waiting
Post-dates monitoring begins at 41 weeks in most practices — a non-stress test (NST, monitoring fetal heart rate for 20–30 minutes), biophysical profile (ultrasound checking 5 parameters including fluid, movement, and breathing movements), and sometimes Doppler blood flow studies. The Bishop score (cervical ripeness score, 0–13) guides induction method: high Bishop score (favorable cervix, 6+) supports direct oxytocin induction; low Bishop score requires cervical ripening first (prostaglandin gel, misoprostol, or Cook balloon). The evidence: randomized trials (including ARRIVE, 2018) show induction at 39–41 weeks has equivalent or better neonatal outcomes compared to expectant management. The emotional toll of going post-dates is real — discuss your preferences for monitoring frequency and induction timing with your OB at 39 weeks, not 41.
How do I know if I’m in labor at week 40?
Week 40 is the estimated due date — approximately 5% of babies are born on their exact due date; most arrive within 2 weeks either side. If you’re at 40 weeks without signs of labor, your OB will discuss induction options — most practices recommend induction between 41+0 and 42+0 weeks due to increasing placental insufficiency risk after 41 weeks. Signs of labor to monitor: contractions 5 minutes apart for 1 hour, rupture of membranes (any fluid loss — go in), bloody show. If no labor by 40+3 to 40+7, expect your OB to schedule a non-stress test (NST) to monitor fetal wellbeing.
Practical Tips for Week 40
- Sleep on your left side — it optimizes blood flow to the placenta and reduces vena cava compression.
- Start kick counts from week 28 — 10 movements in 2 hours is the standard guideline; call your provider if concerned.
- Pack your hospital bag by week 35 — babies don’t always wait until their due date.
- Practice perineal massage from week 34 to reduce tearing risk at birth.
- Attend all prenatal appointments — monitoring frequency increases in the third trimester for good reason.
- Discuss your birth preferences with your provider before week 36.
When to Call Your Midwife or OB
In the third trimester, call your provider immediately for: fewer than 10 fetal movements in 2 hours, regular painful contractions before 37 weeks, severe persistent headache with visual changes or facial swelling (preeclampsia warning signs), any bleeding, signs of water breaking, or any gut feeling that something isn’t right. From week 40, always err on the side of calling — your team would always rather you check in unnecessarily than miss something important.
Frequently Asked Questions
How do I know if I’m in labor?
True labor contractions are regular, progressively stronger, longer, and closer together — and they don’t stop with rest, hydration, or position changes (unlike Braxton Hicks). They typically start every 10–15 minutes and intensify over hours. Other labor signs include: bloody show (pink-tinged mucus from the cervical plug), your water breaking, and lower back pain that radiates to the front. The 5-1-1 rule for hospital: contractions every 5 minutes, lasting 1 minute, for 1 hour.
Is extreme fatigue normal at week 40?
Absolutely. Third trimester fatigue combines extra physical weight, disrupted sleep, frequent urination, and the enormous metabolic cost of a baby gaining half a pound weekly. Your cardiac output is 30–50% above baseline, your kidneys filter 50% more blood, and your body produces extra blood, hormones, and nutrients continuously. Rest is not laziness at this stage — it is medically appropriate preparation.
What is the mucus plug and when does it come out?
The mucus plug is a thick collection of cervical mucus that seals the cervix throughout pregnancy to protect against infection. It can come out days or even weeks before labor, or during early labor itself. It may be clear, white, yellow, or tinged with pink or brown blood. Losing it doesn’t mean labor is imminent, but it does mean your cervix is beginning to prepare. Any bright red bleeding should always be reported to your provider.
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Related Reading
- 20 weeks pregnant: halfway there – anatomy scan guide
- Postpartum recovery: week-by-week what to expect
- I hated being pregnant – and that’s allowed
- Due date calculator: find your exact pregnancy timeline
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