Table 1.
Personal characteristics of cohort, presented for whole cohort and according to expectant management or termination of pregnancy for medical reasons
| Characteristics | Whole cohort (n=364) | Management group | Comparison of management groups (P value) | |
| Expectant (n=251) | Termination for medical reasons (n=113) | |||
| Mean (SD) maternal age (years) | 32 (6) | 32 (6) | 33 (5) | 0.265 |
| Maternal smoking at booking appointment | 81 (22) | 61 (24) | 20 (18) | 0.151 |
| Maternal body mass index: | ||||
| <18.5 | 11 (3) | 9 (4) | 2 (2) | 0.805 |
| 18.5-<25.0 | 134 (37) | 95 (38) | 39 (35) | |
| 25.0-<30.0 | 92 (25) | 59 (24) | 33 (29) | |
| 30.0-<35 | 56 (15) | 39 (16) | 17 (15) | |
| ≥35.0 | 51 (14) | 36 (14) | 15 (13) | |
| Not specified | 20 (5) | 13 (5) | 7 (6) | |
| Maternal ethnic group: | ||||
| Asian | 62 (17) | 42 (17) | 20 (18) | 0.644 |
| Black | 35 (10) | 23 (9) | 12 (11) | |
| Mixed or any other ethnic group | 14 (4) | 10 (4) | 4 (4) | |
| White | 248 (68) | 171 (68) | 77 (68) | |
| Not specified | 5 (1) | 5 (2) | 0 (0) | |
| Obstetric history: | ||||
| Primiparous | 155 (43) | 104 (41) | 51 (45) | 0.569 |
| At least one previous pregnancy affected by PPROM, mid-trimester loss, or preterm birth | 63 (17) | 40 (16) | 23 (20) | 0.303 |
| Singleton pregnancy | 326 (90) | 223 (89) | 103 (91) | 0.506 |
| Amniocentesis or chorionic villous sampling in pregnancy | 10 (3) | 6 (2) | 4 (4) | 0.535 |
| Cervical cerclage before PPROM | 29 (8) | 22 (9) | 7 (6) | 0.402 |
| Median (IQR) gestational age at PPROM (weeks+days) | 19+3 (17+6-21+1) | 19+6 (18+2-21+2) | 18+6 (17+2-20+2) | 0.000 |
Data are number (%) unless indicated otherwise. IQR=interquartile range; PPROM=preterm prelabour rupture of membranes; SD=standard deviation.