Week 42
Your baby is the size of a watermelon
You're 42 weeks. Forty-second. Past every textbook deadline, every friend's prediction, every 'this baby will be early' guess. Per ACOG Practice Bulletin #146 (reaffirmed 2024), 42 weeks is when 'postterm' starts and induction shifts from option to recommendation, with a hard ceiling at 42 weeks and 6 days. Here's what 42 actually means, what the cesarean and dysmaturity numbers really say, and why your provider is moving now.
Key takeaways
- 42 weeks 0 days is the cutoff for 'postterm' per ACOG Practice Bulletin #146 (reaffirmed 2024). Induction is recommended after 42 and no later than 43 weeks.
- About 1 in 5 postterm babies show signs of dysmaturity per Galal et al. (Facts Views Vis Obgyn, 2012). Thin, peeling skin, long nails, sparse vernix. Not a defect. The visual fingerprint of a placenta that's been running on overtime.
- Macrosomia jumps from roughly 0.8 to 1% at term to 2.5 to 10% at postterm per the same review. Bigger baby raises the shoulder-dystocia risk during delivery, and your provider's induction plan is built around it.
- Roughly 80% of women reaching 42 weeks have an unfavorable Bishop score per the Galal review. That's why cervical ripening (balloon, prostaglandin, or both) is almost always step one before pitocin.
About 1 in 5 postterm babies show signs of dysmaturity, and here's what that actually looks like
From your baby's side, the build is done. Surfactant has been mature since week 39. Subcutaneous fat is in place. Brain development continues, but that work doesn't pause for delivery and won't be 'finished' for years either way.
What's changing at 42 weeks is the placenta.
Per Galal et al. (Facts Views Vis Obgyn, 2012) reviewing the postterm pregnancy literature, about 1 in 5 postterm babies show postmaturity (also called dysmaturity) syndrome, first described by Clifford in 1954. Thin, dry, peeling skin. Long fingernails. Sparse vernix. Less subcutaneous fat. Frequently meconium-stained.
Not a defect. A picture of a placenta that's been running past its operating window.
The other side of placental aging is fluid. Amniotic volume tends to keep dropping past 42 weeks, which is exactly why your provider is doing fluid checks at every visit.
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.
Big kicks become smaller pushes now. The overall pattern should still feel steady.
The cesarean rate at 42 weeks is roughly double the term rate, and why ACOG drew the hard line at 43
OK. Here's the part that matters now that you're past 42.
Per Galal et al. (Facts Views Vis Obgyn, 2012), summarizing the postterm vs term literature:
- Cesarean delivery roughly doubles (about 14% at postterm versus about 7% at term, per Rand 2000 and Alexander 2000 cited in the review).
- Severe (third- or fourth-degree) perineal lacerations climb from 2.6% to 3.3%.
- Labour dystocia jumps from 2 to 7% at term to 9 to 12% at postterm.
- Fetal macrosomia (≥4.5 kg) rises from 0.8 to 1% at term to 2.5 to 10% at postterm.
Different comparison than Week 41, by the way. Alkmark compared induction at 41 versus expectant management to 42 (cesarean rates didn't move). The Galal numbers compare delivery at postterm versus delivery at term, which is what matters now that you're here.
Bigger baby plus tired placenta is why the induction plan is moving.
If your Bishop score is under 6 (per the Galal review, roughly 80% of women at 42 weeks are in that bucket), cervical ripening (a balloon catheter, a prostaglandin, or both, as covered at week 38) runs first. Pitocin follows once the cervix is favorable.
Continuous fetal monitoring runs throughout.
For dads
Here's your move:
Stage the postpartum recovery items at the foot of the bed tonight. Not in the closet. Not in the suitcase. At the foot of the bed where she can see them. The Frida kit, the mesh underwear, the perineal spray, the nipple butter, the nursing pads, the newborn sleeper gowns, and the muslin swaddle. Lay them out so she walks past competence, not chaos. Then load the hospital bag into the car. Confirm the power strip is in the side pocket, the chargers are zipped to the front, the labor robe is on top, and the birthing ball is by the door for the slow latent hours. If induction is scheduled this week, you may be in that room for 24 hours or longer. Phones have to last. So do both of you.
Real talk:
She's done. Not 'tired.' Done. Eight weeks of trying to sleep on her side and breathe through her ribs. Two weeks of well-meaning relatives asking if anything's happening yet. A week of monitoring appointments where she stares at a screen counting somebody else's heartbeats. Skip the 'almost.' The word 'almost' has been a lie for a month. What lands: 'You've done all of this. Whatever happens in that room, you've already done the hard part.' Then go quiet. Sit close. Hand her water. The newborn-shift muscle you're about to need for the next year starts in this hospital room. Quiet competence. That's it.
Common concerns
What does an induction at 42 weeks actually look like?+
It depends on your cervix. Per the Galal review, roughly 80% of women at 42 weeks have a Bishop score under 6, so cervical ripening usually goes first. A Foley balloon, a prostaglandin, or both. Pitocin follows once the cervix is favorable. Continuous fetal monitoring runs throughout. Plan for 24 hours or more, especially for a first-time labor.
Will my baby look 'normal' at 42 weeks, or like a postmaturity baby?+
Most babies born at 42 weeks look a lot like a 40-weeker. Per the Galal review, about 1 in 5 postterm babies show some dysmaturity features: peeling skin, long nails, sparse vernix, meconium staining. Visible. Resolves over the first weeks. Your pediatrician will assess any specific findings. This is not the same as a developmental concern.
How worried should I be about shoulder dystocia?+
Concerned, not panicked. Macrosomia (≥4.5 kg) is more common at postterm. 2.5 to 10% versus 0.8 to 1% at term per the Galal review. Bigger baby raises shoulder-dystocia risk during delivery. Your provider trains for this and follows a specific protocol if it happens. Ask about your estimated fetal weight and the plan at your next visit.
What if I just don't go into labor and the induction stalls?+
If cervical ripening doesn't produce a favorable Bishop and the baby is doing well on monitoring, your provider may recommend a planned cesarean rather than continuing to push induction. That's not failure. Per ACOG #146, the goal past 42 is a safe delivery before 43, not vaginal at all costs. Talk through both paths with your provider now so you're not deciding in the middle of it.
Product picks for week 42
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Frida Mom 11pc Postpartum Essentials Kit
Peri bottle, ice maxi pads, healing foam, disposable underwear, and pad liners in one box. The grab-and-go recovery bundle for the first 24 hours after delivery.
Earth Mama Herbal Perineal Spray (2-Pack)
Witch hazel and herb spray for perineal soothing after delivery. Especially relevant after the higher perineal-laceration rates seen at postterm.
Earth Mama Organic Nipple Butter 2 fl oz
Lanolin-free organic nipple cream for the first nursing sessions. Standard hospital-bag inclusion for breastfeeding plans.
Sources
- ACOG, Management of Late-Term and Postterm Pregnancies: Practice Bulletin No. 146 (August 2014, reaffirmed 2024) — https://www.acog.org/clinical/clinical-guidance/practice-bulletin/articles/2014/08/management-of-late-term-and-postterm-pregnancies
- Galal M, Symonds I, Murray H, Petraglia F, Smith R. Postterm pregnancy. Facts Views Vis Obgyn. 2012;4(3):175-187 — https://pmc.ncbi.nlm.nih.gov/articles/PMC3991404/
- Clifford SH. Postmaturity with placental dysfunction: clinical syndrome and pathologic findings. J Pediatr. 1954;44(1):1-13 — https://pubmed.ncbi.nlm.nih.gov/13131189/
- ACOG, When Pregnancy Goes Past Your Due Date (Patient FAQ) — https://www.acog.org/womens-health/faqs/when-pregnancy-goes-past-your-due-date
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.