Volume 52, Issue 1, January 2023, 102498AbstractObjective

To identify risk factors for moderate or severe hypoxic-ischemic encephalopathy (HIE), or neonatal death in clinical placental abruption.

Material and methods

A nested case-control study within a cohort of singleton pregnancies complicated by placental abruption with a live born infant at two academic reference centers in France, from 2006 to 2019. Cases were patients who gave birth to an infant with moderate or severe HIE or death within 28 days (HIE/death group), and controls were patients whose infant did not have any of these outcomes (no-HIE group). Independent risk factors were identified by logistic regression. Binary decision tree discriminant (CART) analysis was performed to define high-risk subgroups of HIE or death.

Results

Among 152 patients, the infants of 44 (29%) had HIE or death. Out-of-hospital placental abruption and fetal bradycardia at admission were more frequent in cases than in controls: 39 (89%) vs 61 (56%), p < .01 and 24 (59%) vs 19 (18%), p < .01, respectively. In multivariate analysis, out-of-hospital placental abruption (aOR, 7.05; 95% CI, 1.94-25.66) and bradycardia at admission (aOR, 8.60; 95% CI, 2.51-29.42) were independently associated with an increased risk of HIE or death. The combination of out-of-hospital placental abruption and bradycardia was the highest risk situation associated with HIE or death (67%). The decision-to-delivery interval was 15 [12-20] minutes among cases.

Conclusion

Out-of-hospital placental abruption combined with bradycardia at admission was associated with a major risk of moderate or severe HIE or death. An optimal decision-to-delivery interval does not guarantee the absence of an adverse neonatal outcome.

Introduction

Placental abruption, defined as premature detachment of the placenta before birth, occurs in 0.4–1% of all pregnancies [1]. It can cause asphyxia, neurological sequelae, and perinatal death. Reported rates of stillbirth range from 3.4% to 51.8%, and neonatal death rates from 1.1% to 19% among the live born infants [2]. Neonatal death in these situations is mainly due to prematurity-related consequences and birth-related asphyxia [3]. Placental abruption has also been associated with a higher risk of hypoxic-ischemic encephalopathy (HIE), found in 17% of infants with HIE compared with 1% of controls [4].

The location of occurrence of placental abruption, in-hospital or out-of-hospital, has not been studied. The interval between initial symptoms and delivery might be longer for out-of-hospital placental abruption and could thus be associated with prolonged asphyxia and a higher risk of neonatal mortality among live born infants. When placental abruption occurs out of hospital and the fetus is alive at admission, an emergency cesarean delivery is usually performed. A better understanding of the determinants associated with neonatal complications could help to identify preventive actions, but little is currently known about the risk factors for adverse neonatal outcomes in this situation.

The objective of our study was to identify risk factors for moderate or severe hypoxic-ischemic encephalopathy, or neonatal death, in clinical placental abruption. Our hypothesis is that out-of-hospital placental abruption is a major risk factor for moderate or severe hypoxic-ischemic encephalopathy or neonatal death.

Section snippetsMaterial and methods

This two-center nested case-control study took place at two academic reference centers in France (center 1: 5,500 births annually; center 2: 3,500 births annually). To have similar number of patients in both centers, data were collected for the years 2012–2019 at center 1 and 2006–2019 at center 2.

All singleton pregnancies complicated by placental abruption confirmed at delivery, and with a live born infant were eligible for this analysis. After excluding multiple pregnancies, medical

Results

During the study period, 176 placental abruptions (0.2%) occurred among 95,450 births. Placental abruption was associated with stillbirth in 22 cases, termination of pregnancy in one case, and triplet pregnancy in another. After these exclusions, 152 infants were included; 44 (29%) of them had moderate or severe HIE and/or died in the neonatal period (Fig. 1).

Table 1 summarizes the maternal and obstetric characteristics in the two groups. Maternal characteristics, chronic condition

Principal findings

A 7-fold increase in the rate of moderate or severe encephalopathy or death was associated with out-of-hospital placental abruption. The highest risk situation of moderate or severe encephalopathy or death was the combination of out-of-hospital placental abruption and bradycardia at admission.

Results in the context of what is known

A retrospective study of 33 cases of out-of-hospital abruption associated with fetal bradycardia at admission reported a high risk of unfavorable neonatal outcomes (33%) (8 neonatal deaths, 3 cerebral

Funding

This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors.

Declarations of interest

None.

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