Table 3.
Adjusted Relative Risk for Neonatal Outcomes According to Presence or Absence of Placental Abruption, Conditioned on Gestational Age at Delivery, Consortium on Safe Labor Study, 2002–2008a
| Neonatal Outcome | Term, ≥37 Weeks (n = 197,218) | Preterm, <37 Weeks (n = 26,123) | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| No Abruption | Abruption | RR | 99% CIb | No Abruption | Abruption | RR | 99% CIb | |||||
| No. | % | No. | % | No. | % | No. | % | |||||
| Composite perinatal-neonatal outcomec | 1.4 | 1.3, 1.5 | 1.3 | 1.3, 1.4 | ||||||||
| No | 143,412 | 73.4 | 939 | 55.6 | 8,822 | 36.5 | 256 | 13.3 | ||||
| Yes | 52,118 | 26.6 | 749 | 44.4 | 15,370 | 63.5 | 1,675 | 86.7 | ||||
| Newborn resuscitationd | 1.3 | 1.3, 1.4 | 1.3 | 1.2, 1.4 | ||||||||
| No | 152,757 | 78.3 | 1,070 | 64.5 | 15,857 | 67.6 | 1,014 | 55.5 | ||||
| Yes | 42,349 | 21.7 | 589 | 35.5 | 7,599 | 32.4 | 812 | 44.5 | ||||
| NICU admissiond | 1.9 | 1.6, 2.2 | 1.5 | 1.5, 1.6 | ||||||||
| No | 181,549 | 93.0 | 1,412 | 85.1 | 11,637 | 49.6 | 384 | 21.0 | ||||
| Yes | 13,557 | 7.0 | 247 | 14.9 | 11,819 | 50.4 | 1,442 | 79.0 | ||||
| NICU LOS, daysd,e | 3 (2–7) | 4 (2–7) | 1.0f | 0.7, 1.2f | 15 (6–34) | 26 (10–52) | 1.4f | 1.3, 1.5f | ||||
| Respiratory distress syndromed | 3.3 | 2.0, 4.6 | 2.1 | 1.9, 2.2 | ||||||||
| No | 193,886 | 99.4 | 1,615 | 97.4 | 18,259 | 77.8 | 984 | 53.9 | ||||
| Yes | 1,220 | 0.6 | 44 | 2.6 | 5,197 | 22.2 | 842 | 46.1 | ||||
| Apnead,g | 2.6 | 1.2, 4.1 | 1.9 | 1.7, 2.1 | ||||||||
| No | 175,089 | 99.5 | 1,578 | 98.5 | 18,893 | 85.0 | 1,276 | 72.5 | ||||
| Yes | 850 | 0.5 | 24 | 1.5 | 3,330 | 15.0 | 483 | 27.5 | ||||
| Asphyxiad | 7.3 | 2.8, 11.9 | 3.7 | 2.2, 5.1 | ||||||||
| No | 194,805 | 99.9 | 1,639 | 98.8 | 23,246 | 99.1 | 1,769 | 96.9 | ||||
| Yes | 301 | 0.1 | 20 | 1.2 | 210 | 0.9 | 57 | 3.1 | ||||
| Antepartum or intrapartum stillbirth | 9.4 | 4.4, 14.3 | 1.7 | 1.3, 2.2 | ||||||||
| No | 195,106 | 99.8 | 1,659 | 98.3 | 23,456 | 97.0 | 1,826 | 94.6 | ||||
| Yes | 424 | 0.2 | 29 | 1.7 | 736 | 3.0 | 105 | 5.4 | ||||
| Neonatal mortality (≤28 days)d | –h | –h | 2.4 | 1.6, 3.1 | ||||||||
| No | 194,968 | 99.9 | 1,655 | 99.8 | 22,964 | 97.9 | 1,740 | 95.3 | ||||
| Yes | 138 | 0.1 | 4 | 0.2 | 492 | 2.1 | 86 | 4.7 | ||||
Abbreviations: CI, confidence interval; LOS, length of stay; NICU, neonatal intensive care unit; RR, relative risk.
a The stratified risk estimates did not show evidence for potential collider bias, and therefore uncorrected estimates were reported here. Corrected estimates for the preterm stratum are available in Web Table 1.
b Relative risk estimated with modified Poisson model adjusting for maternal age, race/ethnicity, parity, prepregnancy body mass index, maternal comorbidities (chronic hypertension, gestational hypertension, preeclampsia, pregestational diabetes, and gestational diabetes), insurance, marital status, smoking status, alcohol use, drug use, and study site. All comparisons significant at P < 0.001, except NICU LOS in the term group.
c Composite outcome included resuscitation, NICU admission, respiratory distress syndrome, apnea, asphyxia, stillbirths, and neonatal mortality.
d Excluding antepartum and intrapartum stillbirths.
e Data are given as median values (interquartile ranges) among those admitted to NICU; excludes sites 4 and 8, which did not report NICU LOS.
f Incidence rate ratio estimated with negative binomial model.
g Excluding site 6, which did not report neonatal apnea.
h Too few neonatal deaths among abruption group for model convergence.