Birth weight percentiles among preterm and term stillbirths and live births.

Birth weight for GA at death (stillbirths) or delivery (live births) by the SCRN algorithm [17]. Percentages may add to slightly more or less than 100% because of rounding.aUnadjusted OR for stillbirth for infants with birth weight in the percentile group shown compared to infants in the reference group from a logistic regression model that included effects for percentile group only.bAnalysis weights that accounted for the basic study design plus other aspects of the sampling were used.In the subset used to assess risk of preterm stillbirth, unweighted sample sizes were 433 preterm stillbirths and 1,821 (preterm and term) live births. In the subset of term pregnancies, unweighted sample sizes were 94 stillbirths and 1,386 live births.cIndividualized norm percentiles were derived using the fetal weight for GA equation from Bukowski et al. [15].dUltrasound norm percentiles were derived using the fetal weight for GA equation and standard error from Hadlock et al. [19].eAlexander et al. population norm percentiles of birth weight for GA were used [18].Simple linear interpolation was used with the Alexander et al. birth weight percentiles reported for completed weeks of GA in whole weeks to derive birth weight percentiles for GA in weeks and days.LB, live birth; SB, stillbirth.