Study population
The entry criteria were fulfilled by 131,514 singleton pregnancies; there were 131,037 livebirths and 477 (0.36%) stillbirths, including 441 (0.34%) antepartum and 36 (0.03%) intrapartum stillbirths. The maternal and pregnancy characteristics in stillbirths and livebirths in the study population are summarised in Table 1.
The gestational age distribution of antepartum stillbirths was <32 weeks in 45.6% (201/441) of cases, <37 weeks in 67.3% (297/441) of cases and at ≥37 weeks in 32.7% (144/441) of cases. The gestational age and birthweight distribution of the antepartum stillbirths is shown in Figure 1. The birthweight was <10th percentile in 55.1% (243/441) of all antepartum stillbirths, including 78.6% (158/201) of those at <32 weeks’ gestation, 69.4% (206/297) at <37 weeks, and 25.7% (37/144) at ≥37 weeks. The birthweight was <10th percentile in 93.1% (243/261) of all placental dysfunction related stillbirths, including 98.1% (158/161) of those at <32 weeks’ gestation, 96.7% (206/213) at <37 weeks, and 78.7% (37/47) at ≥37 weeks.