Table 1.
Baseline characteristics of intention to treat population. Values are numbers (percentages) unless stated otherwise
| Variables | Induction group (n=1381) | Expectant management group (n=1379) |
|---|---|---|
| Age at randomisation (years): | n=1381 | n=1379 |
| Mean (SD) age | 31.2 (4.7) | 31.1 (4.5) |
| Median (interquartile range) | 31.1 (28.0-34.6) | 30.9 (27.9-34.2) |
| <35 years | 1078/1381 (78.1) | 1100/1379 (79.8) |
| ≥35 years | 303/1381 (21.9) | 279/1379 (20.2) |
| Parity: | ||
| Nulliparous | 762/1381 (55.2) | 753/1379 (54.6) |
| Parous | 619/1381 (44.8) | 626/1379 (45.4) |
| Smoking at first antenatal visit (cigarettes/day): | ||
| 0 | 1242/1274 (97.5) | 1228/1276 (96.9) |
| 1-9 | 25/1274 (2.0) | 30/1276 (2.4) |
| ≥10 | 7/1274 (0.5) | 9/1276 (0.7) |
| Alcohol screening at first antenatal visit (points)*: | ||
| 0-5 (low risk) | 1102/1197 (92.1) | 1109/1190 (93.2) |
| ≥6 (risky behaviour) | 95/1197 (7.9) | 81/1190 (6.8) |
| Medical history: | ||
| Psychiatric disorder | 95/1001 (9.5) | 108/997 (10.8) |
| Prepregnancy diabetes type 1 or 2 | 2/1365 (0.1) | 0/1355 (0.0) |
| Endocrine disease | 83/1362 (6.1) | 97/1355 (7.2) |
| Chronic hypertension | 2/1362 (0.1) | 1/1353 (0.1) |
| Height at first antenatal visit (cm): | n=1275 | n=1273 |
| Mean (SD) | 167.5 (6.2) | 167.6 (5.9) |
| Median (interquartile range) | 167 (163-172) | 168 (163-172) |
| Weight at first antenatal visit (kg): | n=1247 | n=1241 |
| Mean (SD) | 70.0 (14.3) | 70.7 (14.5) |
| Median (interquartile range) | 67 (60-77) | 68 (60-77) |
| BMI at first antenatal visit: | n=1275 | n=1265 |
| Mean (SD) | 24.9 (4.7) | 25.1 (4.9) |
| Median (interquartile range) | 23.9 (21.6-27.1) | 24.0 (21.7-27.4) |
| <30 | 1118 (87.7) | 1081 (85.5) |
| ≥30 | 157 (12.3) | 184 (14.5) |
| Last recorded weight during pregnancy (kg): | n=1344 | n=1336 |
| Mean (SD) | 83.5 (14.4) | 84.0 (14.6) |
| Median (interquartile range) | 82.0 (74.0-91.0) | 82.0 (74.0-92.0) |
| Region of birth: | ||
| Sweden | 1069/1289 (82.9) | 1070/1298 (82.4) |
| Other Nordic country | 74/1289 (5.7) | 84/1298 (6.5) |
| Europe outside Nordic countries | 20/1289 (1.6) | 18/1298 (1.4) |
| Outside Europe | 126/1289 (9.8) | 126/1298 (9.7) |
| Educational level: | ||
| <9 years compulsory school | 7/1221 (0.6) | 10/1242 (0.8) |
| 9 years compulsory school | 47/1221 (3.8) | 47/1242 (3.8) |
| 10-12 years (high school) | 378/1221 (31.0) | 405/1242 (32.6) |
| University or similar | 789/1221 (64.6) | 780/1242 (62.8) |
| Employment status: | ||
| Employed | 1098/1296 (84.7) | 1105/1301 (84.9) |
| Student | 101/1296 (7.8) | 101/1301 (7.8) |
| Maternity leave | 47/1296 (3.6) | 52/1301 (4.0) |
| Unemployed | 17/1296 (1.3) | 18/1301 (1.4) |
| Sick leave | 15/1296 (1.2) | 9/1301 (0.7) |
| Other | 18/1296 (1.4) | 16/1301 (1.2) |
| Living status: | ||
| Cohabitation with partner | 1215/1360 (89.3) | 1211/1353 (89.5) |
| Living alone | 19/1360 (1.4) | 21/1352 (1.6) |
| Mode of conception: | ||
| Assisted (IVF/ICSI) | 67/1381 (4.9) | 53/1379 (3.8) |
| Subfertility | 160/1250 (12.8) | 146/1199 (12.2) |
BMI=body mass index; IVF=in vitro fertilisation, ICSI=intracytoplasmic sperm injection.
*
Alcohol screening by AUDIT (alcohol use disorders identification test) tool according to antenatal care routines.20