Neonatal Outcomes after Combined Opioid and Nicotine Exposure in Utero: A Scoping Review

Background: The majority of women who are pregnant with opioid use disorder (OUD) also smoke tobacco but are rarely offered tobacco cessation counseling. While the effects of exposure to opioids and nicotine in utero are well-understood separately, understanding the impact of the combined exposure to these substances on neonatal outcomes is lacking. Methods: A scoping review was conducted using PubMed and Scopus databases for studies addressing the combined exposure to opioids and nicotine during pregnancy published between 1 January 1980 and 9 July 2019. A total of 29 papers met the eligibility criteria for inclusion, with nine being identified as clinical trials (three from the MOTHER study) and two as secondary data analysis of clinical trial data. Results: Neonatal outcomes for infants who had a combined exposure to opioids and nicotine in utero indicated a reduction in birth weight and birth length. Findings in infants exposed to both nicotine and opioids were mixed with regard to the duration of neonatal abstinence syndrome (NAS), the likelihood of treatment for NAS, doses of medicine used to treat NAS, and NAS scores when compared with infants who had opioid exposure without nicotine. Conclusions: The combined exposure to nicotine and opioids during pregnancy may lead to a reduction in neonatal birth weight and birth length and more severe NAS signs, compared with opioid use alone, but more research is necessary to identify the minimum dosage and length of nicotine exposure to accurately predict these outcomes.