Who delivers in each state: the size of every Robson group in all 50 states and the District of Columbia · 2016–2024 · observed counts, not predictions
This page shows only how large each group is. It does not show cesarean rates.
Each cell gives the group’s share of all the state’s deliveries, with the count underneath as n / total. The United States row stays at the top for comparison. Click any column heading to rank the states on that group; click again to reverse the order.
Groups 2 and 4 are shown whole: 2 = 2a + 2b and 4 = 4a + 4b. The split is in the second table.
2a and 4a: labor induced. 2b and 4b: cesarean before labor (not induced, no trial of labor recorded). These groups depend on clinical decisions as well as on the women delivering.
Source. CDC WONDER, Natality 2016–2024 expanded, extracted 4 October 2026, by mother’s state of legal residence, because the natality public use file carries no geography. Hospital births to residents of the 50 states and the District of Columbia with a known final route and method of delivery: 32,291,895 deliveries over 2016–2024 (3,813,197 in 2016; 3,483,135 in 2024).
The unit is the delivery, not the baby. Singletons are counted once, twin pregnancies once (second-born record) and higher-order pregnancies once (set order third or higher). WONDER collapses set order at “3rd or higher”, so a quadruplet or higher-order set can contribute more than one record.
Groups. Nulliparous means live birth order 1; term means 37 completed weeks or more by the obstetric estimate. 1: nulliparous, singleton cephalic, term, spontaneous labor. 2: the same, labor induced (2a) or cesarean before labor (2b). 3 and 4: the same for multiparous women without a previous cesarean. 5: singleton cephalic, term, previous cesarean. 6: nulliparous breech. 7: multiparous breech. 8: multiple pregnancy. 9: singleton, presentation recorded as “Other”. 10: singleton cephalic, 36 weeks or less. Records whose presentation, gestational age, parity or previous cesarean was not stated are carried as Unclassified, so every state’s groups add to its whole.
Small numbers. CDC WONDER suppresses counts of one to nine. The only suppressed counts were state-year triplet deliveries; these were filled from the national total for the year in proportion to each state’s twin deliveries, so group 8 for a single state and year can differ from the true count by a few deliveries. Any cell of one to nine deliveries is shown as “<10” without a percentage.
Reading the table. Robson’s order applies: look at data quality first. Group 9 and the unclassified share vary between states largely with how the birth certificate is completed. Groups 2 and 4, and their split into a and b, depend on how labor began, which is a clinical decision recorded in tick boxes completed differently from state to state.
Suggested citation. Centers for Disease Control and Prevention, National Center for Health Statistics. National Vital Statistics System, Natality on CDC WONDER Online Database. Data are from the Natality Records 2016–2024. Accessed 4 October 2026.