Live Births per 100 Couples at 24 months of Natural Procreative Technology Treatment by Characteristics of Couples Beginning Treatment
| Couple Category | Couples (n) | Live Births (n) | Crude Proportion | Adjusted Proportion* |
|---|---|---|---|---|
| All couples | 1072 | 273 | 25.5 | 52.8 |
| Woman's age (years) | ||||
| ≤30 | 86 | 29 | 33.7 | 59.1 |
| >30–35 | 412 | 134 | 32.5 | 58.6 |
| >35–40 | 423 | 89 | 21.0 | 46.1 |
| >40 | 151 | 21 | 13.9 | 50.9 |
| Time spent attempting to conceive (years) | ||||
| 1–3 | 246 | 90 | 36.6 | 66.0 |
| >3–6 | 468 | 129 | 27.6 | 55.4 |
| >6–9 | 210 | 39 | 18.6 | 44.9 |
| >9 | 118 | 14 | 11.9 | 42.8 |
| Previous live birth | ||||
| Yes | 257 | 92 | 35.8 | 73.9 |
| No | 785 | 181 | 23.1 | 48.5 |
| Previous ART attempts (n)† | ||||
| 0 | 702 | 216 | 30.8 | 61.5 |
| 1 | 128 | 29 | 22.7 | 41.9 |
| 2 | 125 | 18 | 14.4 | 34.9 |
| ≥3 | 97 | 10 | 10.3 | 19.8 |
* Adjusted by life-table analysis, where withdrawal or continuing treatment at the end of study follow-up are censoring events. Adjusted proportions should be interpreted with caution because of small numbers in subgroups.
† Assisted Reproductive Technology (ART) includes in vitro fertilization (IVF) with or without intracytoplasmic sperm injection (ICSI).