Table 2.
Characteristics of the study population in relation to the gestational age at delivery
| Total newborn n = 1172 |
Preterm birth < 37 GWS n = 81 (6.9) |
Term birth 37–40 GWS n = 855 (73.0) |
Late-term birth ≥41 GWS n = 236 (20.1) |
|
|---|---|---|---|---|
| Birth weight, g | 3446 ± 597 | 2156 ± 704 | 3497 ± 470 | 3701 ± 395 |
| 1st tertile ≤3280 | 79 (20) | 218 (56) | 94 (24) | |
| 2nd tertile 3281-3700 | 2 (0.5) | 166 (43) | 223 (57) | |
| 3rd tertile ≥3701 | 0 (0) | 131 (34) | 259 (66) | |
| Placental weighta, g | 590 ± 130 | 439 ± 117 | 592 ± 125 | 620 ± 124 |
| 1st tertile ≤530 | 51 (13) | 179 (47) | 155 (40) | |
| 2nd tertile 531–630 | 8 (2.1) | 179 (47) | 196 (51) | |
| 3rd tertile ≥631 | 2 (0.5) | 145 (39) | 225 (61) | |
| Maternal ageb, years | 29.8 ± 5.1 | 30.7 ± 5.4 | 29.9 ± 5.0 | 29.4 ± 5.3 |
| 1st tertile ≤28 | 21 (4.6) | 203 (44) | 233 (51) | |
| 2nd tertile 29–32 | 28 (7.4) | 161 (43) | 188 (50) | |
| 3rd tertile ≥33 | 22 (6.8) | 145 (45) | 155 (48) | |
| Number of previous deliveriesb | 1.0 ± 1.3 | 0.7 ± 1.1 | 1.1 ± 1.3 | 0.7 ± 1.1 |
| Nulliparous | 45 (8.8) | 210 (41) | 258 (50) | |
| Primiparous | 14 (3.9) | 159 (44) | 186 (52) | |
| Multiparous | 12 (4.2) | 140 (49) | 132 (47) | |
| Number of twin pregnancies | 16 (1.4) | 10 (63) | 6 (38) | 0 (0) |
| Gestational week at delivery, weeksb | 39.2 ± 2.0 | 33.5 ± 3.2 | 39.1 ± 0.9 | 41.1 ± 0.3 |
| Foetal sex, males | 589 (50.3) | 42 (51.9) | 443 (51.8) | 104 (44.1) |
| Self-reported smoking before pregnancy | 226 (20) | |||
| Number of daily cigarettes before pregnancyb | ||||
| No smoking | 957 (80) | 60 (6.3) | 715 (75) | 182 (19) |
| 1–10 | 135 (11.7) | 4 (3.0) | 93 (69) | 38 (28) |
| ≥ 11 | 64 (5.5) | 7 (11) | 41 (64) | 16 (25) |
| Self-reported smoking during pregnancy | 49 (4.2) | |||
| Number of daily cigarettes during pregnancyb | ||||
| No smoking | 1104 (96) | 68 (6.2) | 811 (74) | 225 (20) |
| 1–5 | 28 (2.4) | 1 (3.6) | 22 (79) | 5 (18) |
| ≥ 6 | 24 (2.1) | 2 (8.3) | 16 (67) | 6 (25) |
| Self-reported alcohol consumption before pregnancyb, weekly doses (average) | ||||
| None | 601 (52) | 27 (4.5) | 468 (78) | 106 (18) |
| 1–5 | 497 (43) | 40 (8.0) | 343 (69) | 114 (23) |
| ≥ 6 | 58 (5.0) | 4 (6.9) | 38 (66) | 16 (28) |
| Self-reported alcohol consumption during pregnancyb, monthly (average) | ||||
| Never | 1053 (96) | 66 (6.3) | 172 (73) | 215 (20) |
| Less than once | 36 (3.3) | 12 (2.8) | 23 (64) | 12 (33) |
| Once a month, and more | 11 (1.0) | 1 (9.1) | 9 (82) | 1 (9.1) |
Values are n (%) or mean ± SD
aExcluded twin pregnancies, n = 16
bmothers with twin pregnancies included only once, total n = 1156 gestational weeks (GWS)