Table 1.
ProTWIN maternal baseline characteristics, pregnancy outcomes and child neonatal and sociodemographic characteristics of the women participating in the 4‐y follow‐up study
| Maternal characteristics at entry of the ProTWIN trial | n/na | Pessary group (n = 140) | Control group (n = 118) | P value |
|---|---|---|---|---|
| Median (IQR) maternal age at randomization | 140/118 | 32 (29‐36) | 33 (30‐37) | 0.471 |
| Nulliparity, n (%) | 140/118 | 87 (62.1) | 66 (55.9) | 0.312 |
| Smoking during pregnancy, n (%) | 139/114 | 4 (2.9) | 5 (4.4) | 0.735 |
| Previous preterm delivery, n (%)b | 51/52 | 10 (19.6) | 7 (13.5) | 0.438 |
| Parental education, n (%)c | ||||
| High | 134/115 | 102 (76.1) | 89 (77.4) | 0.908 |
| Middle | 20 (14.9) | 15 (13.0) | ||
| Low | 12 (9.0) | 11 (9.6) | ||
| Ethnic origin European, n (%) | 140/118 | 132 (94.3) | 106 (89.8) | 0.234 |
| Monochorionic pregnancy, n (%) | 139/118 | 33 (23.7) | 30 (25.4) | 0.755 |
| Triplet pregnancy, n (%) | 140/118 | 5 (3.6) | 2 (1.7) | 0.459 |
| Cervical length (mm), median (IQR) | ||||
| Unselected group | 140/118 | 43 (37‐48.75) | 43 (39‐49) | 0.268 |
| Subgroup cervical length <38 mm | 43/18 | 35 (33‐37) | 34 (32‐35.25) | 0.100 |
| Maternal pregnancy outcomes ProTWIN trial | ||||
| Pregnancy duration in weeks median (IQR) | 140/118 | 36.6 (34.4‐37.6) | 36.3 (34.2‐37.4) | 0.417 |
| <28 wk, n (%) | 2 (1.4) | 2 (1.7) | >0.999 | |
| <32 wk, n (%) | 14 (10.0) | 13 (11.0) | 0.790 | |
| <37 wk, n (%) | 71 (50.7) | 62 (52.5) | 0.770 | |
| PPROM, n (%) | 125/99 | 16 (12.8) | 12 (12.1) | 0.879 |
| Tocolytic drug, n (%) | 140/118 | 23 (16.4) | 21 (17.8) | 0.771 |
| Corticosteroids, n (%) | 131/113 | 33 (25.2) | 35 (31.0) | 0.315 |
| Neonatal characteristics of the ProTWIN trial | n/n | Pessary group (n = 281) | Control group (n = 233) | P value |
|---|---|---|---|---|
| Male gender, n (%) | 281/233 | 138 (49.1) | 122 (52.4) | 0.463 |
| Composite primary outcome of the ProTWIN trial, n (%)d | 279/233 | 15 (5.4) | 15 (6.4) | 0.611 |
| Congenital anomalies, n (%) | 277/233 | 9 (3.2) | 9 (3.9) | 0.811 |
| Birthweight, n (%) | ||||
| <2500 g | 280/233 | 147 (52.5) | 134 (57.5) | 0.256 |
| <1500 g | 32 (11.4) | 22 (9.4) | 0.465 | |
| Social background of the children at 4 y of age | ||||
| Age at follow‐up, mean (SD) | 281/233 | 3.98 (0.19) | 3.96 (0.21) | 0.198 |
| Living in two parent family, n (%)e | 275/233 | 269 (97.8) | 230 (98.7) | 0.517 |
| Twins are eldest of the siblings, n (%) | 277/233 | 169 (61.0) | 128 (54.9) | 0.166 |
| Dutch primary language spoken at home, n (%) | 275/231 | 269 (97.8) | 229 (99.1) | 0.300 |
| Bilingual, n (%) | 277/233 | 40 (14.4) | 34 (14.6) | 0.961 |
| Daycare, n (%) | 277/233 | 256 (92.4) | 217 (93.1) | 0.757 |
| Breastfed in the first 6 mo, n (%)f | 276/230 | 61 (22.1) | 42 (18.3) | 0.258 |
Number of analyzed mothers or children, without missing data. Pessary group/control group.
Previous preterm delivery, excluding all nulliparous women.
Parental education: “low level” = total years post elementary schooling <6, if at least one of the parents has a low level of education (but not if one parent is highly educated); “middle level” = total years post elementary schooling 6‐8, if both parents have a middle level of education; “high level” = total years post elementary schooling >8, if one of the parents is highly educated.26 Parental education at the time of follow‐up.
Composite outcome of the ProTWIN trial: stillbirth, PVL grade ≥2, RDS grade ≤2, BPD, IVH grade 2B or worse, NEC, proven sepsis, neonatal death until 6 weeks after expected term date.11
Living in two parent family: Children living with one or two biological parents, new marriage and de facto relationship.
Breastfed in the first 6 mo: breastfeeding for at least 6 mo, with or without infant formula.