"Many economic, psychosocial, behavioral, biological, and health services factors have been implicated in these adverse perinatal outcomes.14,15 Among them are two that seem to be inextricably associated, namely low levels of PNC [Prenatal Care] utilization and exposure to IDU [Illicit Drug Use] in pregnancy.16–21 The overlap between these factors is evident in the population we studied, with a prevalence of 4.2% IDU in mothers with adequate PNC, 26.2% in women with inadequate PNC, and 55.2% in mothers with no PNC."

Source

El-Mohandes A, Herman AA, Nabil El-Khorazaty M, Katta PS, White D, Grylack L. Prenatal care reduces the impact of illicit drug use on perinatal outcomes. J Perinatol. 2003;23(5):354-360. doi:10.1038/sj.jp.7210933