Neurobehaviour of Māori and Non-Māori infants exposed prenatally to methamphetamine.

Abstract

Methamphetamine use during pregnancy is an increasing concern. As more infants become prenatally exposed to methamphetamine the developmental outcomes for these infants remain unknown. The aim of this research was to further the findings on neurobehavioural outcomes for these infants. The first objective was determining if earlier findings from the cross cultural study could be replicated in the New Zealand cohort. Previous findings were that prenatal methamphetamine exposure was associated with unique neurobehavioural outcomes. Secondly to determine if Māori infants displayed differences in neurobehaviour at birth compared to non-Māori. Another question was if maternal route of delivery of methamphetamine had an association with neurobehavioural outcomes. Lastly was the hypothesis that there was an association between neurobehaviour at birth measured by NICU Network Neurobehavioral Scale (NNNS) summary scores and later infant outcomes from 1-3 years of age measured by the Bayley- II scales. General linear models were used to compare NNNS summary scores of 106 infants prenatally exposed to methamphetamine and 115 non-exposed infants controlling for other drug use and contextual factors. These mother-infant dyads were enrolled in the prospective, longitudinal Infant Development, Environment and Lifestyle (IDEAL) study in Auckland, New Zealand. Regression analysis was used to examine the relationship between prenatal methamphetamine exposure of infant by trimester effects and also route of maternal methamphetamine administration (intravenous (IV), smoking, ingesting or snorting). This research replicated earlier results that there were unique effects of prenatal methamphetamine exposure on infant neurobehaviour. Māori infants had no differences in neurobehaviour at birth compared to non-Māori infants irrespective of drug exposure. However Māori methamphetamine exposed infants showed significant differences in neurobehaviour at birth compared to non-exposed Māori infants and were more likely to exhibit signs of CNS stress, more stress abstinence and non-optimal reflexes than non-exposed Māori infants. A unique finding was route of methamphetamine delivery by IV had associations with infant neurobehaviour on summary scores of non-optimal reflexes, hypertonicity, and physiological stress. This study has shown that infant neurobehaviour is associated with Bayley-II psychomotor scores at 12 and 36 months. Evidence from this study has contributed to and found consistencies with previously published research on prenatal methamphetamine exposure.