Non-smokers | Smokers | p Value* | |||
---|---|---|---|---|---|
n/N | % | n/N | % | ||
*Comparison of the distribution of antenatal steroids by risk factors of RDS in non-smokers and smokers. | |||||
†Intrauterine growth retardation defined as a birth weight ratio <0.74.31 | |||||
‡Comparison between five exclusive groups of causes defined in the following order: hypertension, either pre-existing or due to pregnancy; maternal bleeding (abruptio placenta, placenta previa, and other uterine bleeding) without hypertension; preterm premature rupture of membranes (PPROM) without hypertension or bleeding; preterm spontaneous labour without hypertension, bleeding, or PPROM; all other causes, excluding hypertension, bleeding, PPROM of preterm spontaneous bleeding. | |||||
Antenatal steroids | 384/518 | 221/340 | |||
Gestational age (weeks) | |||||
27–28 | 62/92 | 67.4 | 46/72 | 63.9 | 0.63 |
29–30 | 100/128 | 78.1 | 57/85 | 67.1 | |
31–32 | 222/298 | 74.5 | 118/183 | 64.5 | |
IUGR† | |||||
Yes | 112/137 | 81.8 | 52/74 | 70.3 | 0.47 |
No | 271/378 | 71.7 | 169/265 | 63.8 | |
Main cause of preterm birth‡ | |||||
Hypertension | 157/194 | 80.9 | 29/41 | 70.7 | 0.29 |
Bleeding | 81/117 | 69.2 | 72/113 | 63.7 | |
PPROM | 74/91 | 81.3 | 53/81 | 65.4 | |
Spontaneous prelabour | 43/81 | 53.1 | 41/71 | 57.7 | |
Other | 29/35 | 82.9 | 26/34 | 76.5 | |
Caesarean section | |||||
Yes | 271/352 | 77.0 | 132/196 | 67.3 | 0.8 |
No | 112/165 | 67.9 | 89/144 | 61.8 | |
Sex | |||||
Boys | 210/281 | 74.7 | 116/177 | 65.5 | 0.93 |
Girls | 173/236 | 73.3 | 105/163 | 64.4 |