P0720 - Delayed-Interval Delivery in Multiple Gestation Pregnancies: Neonatal Mortality, Morbidity, and Development

Background:

Delayed-interval delivery (DID) is the delivery of the first fetus in a multiple gestation pregnancy without promptly delivering the remaining fetus(es), usually in an attempt to decrease the risk of adverse outcome due to extreme prematurity in the retained fetus(es). Available information on DID is limited, resulting in a knowledge gap of how the benefits of DID in reducing known risks of prematurity are balanced with its complications.

Objective:

Determine the incidence of DID in the NICHD Neonatal Research Network (NRN) and describe short- and long-term outcomes.

Design/

Methods:

Retrospective cohort study of infants born at ≤28 weeks’ gestation between 2006-2019 within the NRN. Infants without a documented birth time were excluded. DID was defined as passage of >24 hrs between birth of firstborn and retained infants. Rates of DID, major morbidities of prematurity, and death were described. Outcomes were compared for firstborn and retained infants born by DID. In addition, outcomes of DID-born infants were compared to those of (1) other multiples, and (2) all infants in the GDB and follow-up datasets (excluding DID-born).

Results:

DID occurred in 2.1% (68/3211) of pregnancies with multiples. Median delay was 103.5 hrs (IQR 53.5-210.8). DID-born multiples were smaller and less mature than other multiples (Table 1). Retained infants experienced significantly less bronchopulmonary dysplasia (BPD) than first-borns (Table 2). Rates of death, BPD, intraventricular hemorrhage (IVH) grade 3-4, sepsis, and other morbidities were higher for DID-born multiples compared to other multiples, as well as all other infants (Table 2). After adjustment for gestational age and birth weight, only necrotizing enterocolitis (NEC) [RR 1.81 (95% CI: 1.10-2.99)] and hearing impairment [RR 3.22 (95% CI: 1.19-8.71)] remained significantly different compared to the general population of multiples. Hearing impairment [RR 3.47 (95% CI: 1.26-9.66)] remained significantly different compared to other infants in the GDB.

Conclusion(s):

Among DID infants, retained infants experience less BPD than firstborns. DID infants, overall, were smaller and less mature than other multiples. Rates of death and morbidities, including sepsis, IVH grade 3-4, NEC, BPD, and hearing impairment, were higher in DID infants. However, after adjustment for birth weight and GA, only NEC and hearing impairment remained significantly higher.