Obstetric and neonatal outcomes by assisted human reproduction (AHR) group and maternal age at delivery*
| Characteristic | No. (%) of non-AHR live births† | No. (%) of AHR live births† | ||||||
|---|---|---|---|---|---|---|---|---|
| < 25 yr n = 76 683 | 25–29 yr n = 140 553 | 30–34 yr n = 176 492 | ≥ 35 yr n = 104 125 | < 25 yr n = 650 | 25–29 yr n = 4000 | 30–34 yr n = 9747 | ≥ 35 yr n = 11 873 | |
| Mode of delivery | ||||||||
| Spontaneous vaginal birth | 32520 (42.2) | 57423 (38.9) | 63641 (36.1) | 31272 (30.0) | 239 (36.8) | 1216 (30.4) | 2550 (26.2) | 2216 (18.7) |
| Induced labour | 14334 (18.7) | 27337 (18.5) | 31056 (17.6) | 18628 (17.9) | 114 (17.5) | 780 (19.5) | 1722 (17.7) | 2045 (17.2) |
| Cesarean delivery | 12969 (16.9) | 29857 (20.2) | 41551 (23.5) | 30204 (29.0) | 163 (25.1) | 1281 (32.0) | 3648 (37.4) | 5551 (46.8) |
| Missing | 15644 (20.4) | 29801 (20.2) | 35530 (20.1) | 20256 (19.5) | 134 (20.6) | 723 (18.1) | 1827 (18.7) | 2061 (17.4) |
| Preterm delivery (< 37 wk) | 6483 (8.5) | 12426 (8.4) | 15430 (8.7) | 10711 (10.3) | 209 (32.2) | 1137 (28.4) | 2973 (30.5) | 3837 (32.3) |
| Prolonged pregnancy (≥ 42 wk) | 210 (0.3) | 327 (0.2) | 423 (0.2) | 292 (0.3) | 0 (0.2) | 6 (0.1) | 9 (0.1) | 11 (0.1) |
| Birth weight, g, mean ± SD | 3329 ± 578 | 3333 ± 563 | 3327 ± 570 | 3285 ± 598 | 2979 ± 816 | 3047 ± 758 | 3036 ± 778 | 3000 ± 746 |
| Median (IQR) | 3352 (3020–3680) | 3358 (3030–3680) | 3350 (3020–3680) | 3320 (2974–3653) | 3110 (2571–3498) | 3160 (2685–3540) | 3150 (2658–3550) | 3100 (2610–3500) |
| Birth weight category, kg | ||||||||
| < 2.5 | 5363 (7.0) | 10008 (6.8) | 12 759 (7.2) | 9049 (8.7) | 172 (26.5) | 1011 (25.3) | 2613 (26.8) | 3262 (27.5) |
| 2.5–4.0 | 61573 (80.3) | 119839 (81.3) | 142046 (80.5) | 81875 (78.6) | 442 (68.0) | 2744 (68.6) | 6522 (66.9) | 8059 (67.9) |
| > 4.0 | 6877 (9.0) | 12964 (8.8) | 15482 (8.8) | 8384 (8.1) | 36 (5.5) | 233 (5.8) | 573 (5.9) | 526 (4.4) |
| Missing | 1654 (2.2) | 1607 (1.1) | 1491 (0.8) | 1052 (1.0) | 0 (0) | 12 (0) | 39 (0.4) | 26 (0.2) |
| Neonatal ICU stay | 7436 (9.7) | 13578 (9.2) | 16116 (9.1) | 10806 (10.4) | 146 (22.5) | 965 (24.1) | 2407 (24.7) | 3133 (26.4) |
| Congenital malformation | 300 (0.4) | 355 (0.2) | 437 (0.3) | 318 (0.3) | 11 (1.7) | 13 (0.3) | 37 (0.4) | 73 (0.6) |
Note: ICU = intensive care unit, IQR = interquartile range, SD = standard deviation.
↵* Interaction term of age (< 25 yr as reference) by group (non-AHR as reference) was significant at 0.05 in adjusted generalized estimating equation models (Wald Test) for cesarean delivery, preterm delivery (< 37 wk), birth weight < 2.5 kg, birth weight 2.5–4.0 kg and congenital malformations.
↵† Unless indicated otherwise.