Thirty-seven weeks is called term. It is also two and a half times the intensive care rate of thirty-nine
A week-by-week table, produced by querying the CDC birth-certificate database directly for this guide.
Everyone in the room uses the word term for anything from 37 weeks onward. Once you pass 37 weeks, most parents believe the intensive care unit is no longer about them. The week-by-week numbers say otherwise, and almost nobody is shown them.
Where this table comes from, because that matters. It is not copied from a published paper. No published paper reports intensive care admission by single week of pregnancy for US single babies. The counts below were pulled directly from CDC WONDER, the public database built from US birth certificates, by querying it for this guide on 27 August 2026. The query covered single babies (not twins or triplets) born in 2024, grouped by the obstetric estimate of gestational age and by whether a NICU admission was recorded on the certificate. The percentages are arithmetic done here on those counts. CDC returned the counts; the rates are derived. Anyone can run the same query and check the work.
| Week of pregnancy at birth | Admitted to the NICU | US single babies born, 2024 | Rate (derived here) |
|---|---|---|---|
| 34 weeks | 35,307 | 42,828 | 82.44% |
| 35 weeks | 24,820 | 59,003 | 42.07% |
| 36 weeks | 26,694 | 130,196 | 20.50% |
| 37 weeks | 44,732 | 436,713 | 10.24% |
| 38 weeks | 31,388 | 619,618 | 5.07% |
| 39 weeks | 50,793 | 1,353,640 | 3.75% |
| 40 weeks | 24,080 | 624,067 | 3.86% |
| 41 weeks | 7,821 | 162,001 | 4.83% |
| 42 weeks | 515 | 8,503 | 6.06% |
Read the two term rows again. At 39 weeks, about 4 babies in 100 go to intensive care. At 37 weeks, about 10 in 100. That is about two and a half times as many, in babies everyone calls term. (That comparison is arithmetic done here on the counts above.)
From 38 weeks back, going a week earlier roughly doubles the rate each time. And look at the bottom of the table: the rate does not keep falling. It bottoms out at 39 and 40 weeks and then turns back up.
What NICU admission actually means on a birth certificate. The federal definition is broad. It is Admission into a facility or unit staffed and equipped to provide continuous mechanical ventilatory support for a newborn. It includes NICU admission at any time during the infant's hospital stay following delivery.
A baby who spends four hours there for observation and a baby who spends four weeks there on a ventilator are both counted in these numbers. That cuts both ways: the rate is not a rate of serious illness, and it is also not nothing.
The national picture, from figures CDC itself published. Across all US births, NICU admission rose from 8.7% in 2016 to 9.8% in 2023. The largest increase of any gestational group was in early term babies, 37 to 38 weeks, who went from 6.2% to 7.1%. Full term babies, 39 to 40 weeks, went from 3.5% to 3.8%. Babies from multiple pregnancies are in a different world entirely: Births in multiple-gestation deliveries are more likely to be admitted to a NICU than singletons (43% of multiples compared with 9% of singletons in 2023)
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Where you give birth may matter as much as when. In 2023 the state rate ran from 4.6% in Rhode Island to 14.2% in Delaware, a threefold spread measured on the same form. The federal report that publishes that spread offers no explanation for it. Neither will this guide; no verified explanation exists, and inventing one would be worse than saying so.
The authors of the largest analysis of the rise, covering 17,896,048 US births from 2007 to 2012, put it this way in their own conclusion: US newborns at all birth weights are increasingly likely to be admitted to a NICU, which raises the possibility of overuse of neonatal intensive care in some newborns.
In 2012, 43.0 per 1,000 normal-weight babies (2,500 to 3,999 g) were admitted, against 844.1 per 1,000 of those under 1,500 g.
"Is there a medical reason to deliver before 39 weeks in my case, or is this about scheduling?"
"What is this hospital's own NICU admission rate for babies born at that week?"
"If my baby does go, what would count as a short stay here?"