Of the estimated 5.4 million women who abused opioid painkillers or heroin in 2016, some 26,000 were pregnant. (Both numbers are likely gross underestimates.) These pregnancies, nearly 9 in 10 of which are unplanned, carry major risks for mother and fetus alike. A woman who injects heroin through her pregnancy is significantly more likely than a nonuser to deliver a preterm baby with serious long-term health problems. Those risks diminish markedly if the mom takes medications to treat the addiction, but even so, the babies are often born in withdrawal. The condition, called neonatal abstinence syndrome, is characterized by high-pitched screaming, trembling, feeding difficulties, and hyperactive reflexes.
Read more here: https://www.motherjones.com/politics/2018/02/pregnant-opioid-drug-use/