688 - Head Circumference Trajectory Amongst Preterm Infants With and Without Neonatal Abstinence Syndrome

Publication Number: 688.5291

Colin McGrath, Rotunda Hospital, Dublin, Dublin, Ireland; Michael Boyle, Rotunda Hospital, Ireland, Dublin, Dublin, Ireland

Background: Maternal opioid dependence is an important predictor of premature delivery with 40% of such women delivering before term compared to 11% of opioid-unexposed women. Identification of drug-withdrawal in preterm infants remains imperfect owing to lack of a validated diagnostic tool and competing hypotheses on the significance of drug-exposure in this cohort. Amongst term infants, opioid-exposure is predictive of smaller birth head circumference (HC) and a dose-response relationship appears to exist. Adverse neurodevelopmental outcome in term newborns has been established. As yet there is little data on such metrics in preterm infants and whether this interacts with the neurodevelopmental morbidity attributable to prematurity.

Objective: To compare antenatally drug-exposed preterm infants with a matched unexposed cohort for HC at birth and discharge.

Design/Methods: A single-centre retrospective chart review was conducted between 2019-2022. Newborns were included where gestational age was < 37 weeks and excluded for congenital anomaly or major comorbidity. Drug exposure was confirmed by antenatal history and urine toxicology. Only opioid and benzodiazepine (BZP) exposure was included for analysis. Groups were matched for gestation, mode of delivery, gender and ethnicity. Finnegan scoring was applied to exposed infants. HC was recorded at birth and discharge. Statistical analyses including t-test, Fisher’s exact and McNemar tests were applied.

Results: Twenty-seven matched pairs of drug-exposed and unexposed preterm infants were analysed. Group characteristics are presented in Table 1. Combined opioid/BZP exposure comprised 48% of cases, followed by opioid-only in 25.9% and BZP-only in 7.4% of cases.

Mean HC at birth was 30.9cm (37th centile) in exposed and 31.6cm (44th centile) in control infants (p >0.05). At discharge, average HC among exposed newborns was 32.2cm (26th centile) and in unexposed controls was 32.5cm (40th centile) (p < 0.05). The proportion of infants with HC < 10th centile rose from 8.7% at birth to 20% at discharge in the exposed cohort. In the unexposed group, 9.1% had a birth HC < 10th centile which fell to 8.7% at discharge. Analysis of within-group change did not reach statistical significance, possibly due to small sample size.

Conclusion(s): The divergence in head growth centiles among drug-exposed preterm infants is a novel finding and may highlight the vulnerability of the premature brain to the deleterious effects of drug-exposure and its treatment. Consequently, maternal drug-use may compound neurodevelopmental morbidity in this cohort and warrant targeted developmental follow-up.

Head Circumference Indices
A comparison of measured head circumference and corresponding centiles at birth and discharge for drug-exposed and unexposed preterm infants.

Group Characteristics
Characteristics At Birth And Discharge Of Drug-Exposed Preterm Infants And Controls