Characteristics of pregnant women who underwent in vitro fertilisation (IVF) and women with natural pregnancies between 1990 and 2008, Sweden. Values are numbers (percentages) unless stated otherwise
| Characteristics | IVF pregnancies (n=23 498) | Natural pregnancies (n=116 960) |
|---|---|---|
| Maternal age at birth: | ||
| 19-24 | 322 (1.4) | 1510 (1.3) |
| 25-29 | 3764 (16.0) | 18 438 (15.8) |
| 30-34 | 10 129 (43.1) | 50 575 (43.2) |
| 35-39 | 8016 (34.1) | 40 083 (34.3) |
| 40-47 | 1267 (5.4) | 6354 (5.4) |
| Mean (SD) age (years) | 33.3 (4.0) | 33.4 (3.9) |
| Median (interquartile range) age (years) | 33 (31-36) | 33 (31-36) |
| Born in Sweden | 20 267 (86.2) | 95 180 (81.4) |
| Prepregnancy body mass index: | ||
| Missing data | 3961 (16.9) | 20 228 (17.3) |
| <25 | 12 490 (53.2) | 62 464 (53.4) |
| 25-29 | 5136 (21.9) | 24 646 (21.1) |
| ≥30 | 1911 (8.1) | 9622 (8.2) |
| Cigarette smoker: | ||
| Missing data | 1793 (7.6) | 7731 (6.6) |
| No | 20 130 (85.7) | 96 996 (82.9) |
| Yes | 1575 (6.7) | 12 233 (10.5) |
| Education (years): | ||
| Missing data | 48 (0.2) | 1027 (0.9) |
| ≤9 | 1789 (7.6) | 11 741 (10.0) |
| 10-12 | 10 588 (45.1) | 50 527 (43.2) |
| >12 | 11 073 (47.1) | 53 665 (45.9) |
| Marital status: | ||
| Missing data | 1800 (7.7) | 7798 (6.7) |
| Married to or cohabiting with father of child | 21 569 (91.8) | 103 882 (88.8) |
| Single | 51 (0.2) | 3,166 (2.7) |
| Other | 78 (0.3) | 2114 (1.8) |