Factors Associated with Maternal Drug Use and the Severity of Neonatal Abstinence Syndrome

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In East Tennessee and Middle Appalachia, the epicenter of the opioid epidemic, approximately 15% of women give birth taking buprenorphine or methadone for opioid addiction (medical assisted therapy--MAT) or using other drugs illicitly and 5% of births are diagnosed with neonatal abstinence syndrome (NAS). A better understanding is needed of factors contributing to the severity of NAS.


To identify maternal and infant characteristics associated with length of stay among newborns with neonatal abstinence syndrome.


Participants were 150 newborns systematically sampled from births diagnosed with NAS during the past 5 years at a single medical center. Data were obtained through abstraction of maternal prenatal records, infant delivery and infant medical charts. The abstraction included maternal and child demographic and clinical characteristics. Drug and other substance use/exposure histories were based on maternal history, and urine and cord tissue drug screening.


The infants’ average length of stay was 18.6 (s.d. = 11.9), 15% were low birthweight, and had an average gestational age of 38.8 (s.d. = 1.8); 62% were male; 49% were breast-fed. The mothers mean age was 27.5 (s.d. = 5.0); mean parity was 1.6 (s.d. = 1.4); 77% were unmarried; 75% had < HS education; and 89% had exposure at some time during pregnancy to other prescription (in addition to buprenorphine or methadone) or illicit opioids. In the least squares regression, which included important potential covariates such as infant sex, birth weight and gestational age, significant predictors of infant length of stay include: maternal benzodiazepine use (8.3 day longer LOS on average; p = 0.019), and infants whose mothers had a history of mental illness (3.9 day longer LOS on average, p = 0.040 ). While infants born to mothers smoking in the final 30 days of pregnancy had a 2.7 day longer LOS on average after adjustment for other significant predictors, this association was no longer significant in regression analysis (p = 0.293).


Maternal use of prescription or illicit opioids leading to NAS is rooted in women’s’ life histories characterized by disadvantage, relationship instability, polysubstance use and mental illness. Efforts to reduce the incidence and severity of NAS among those on MAT during pregnancy should focus on preventing poly-substance misuse and providing supports for other maternal health needs including treating mental illness.


Toronto, CA

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