The cycle of opioid use and withdrawal is particularly devastating for the developing fetus. The repetitive pattern of use and withdrawal leads to fetal hypoxia and uteroplacental insufficiency, with a resultant increased risk of prematurity, fetal demise, and low birth weight. Comprehensive prenatal care is essential for these patients.

Medication-assisted treatment has been the standard of care for pregnant opiate addicts. Methadone, a synthetic opioid, has been used with success in opiate addicts. At appropriate dosages, methadone, a synthetic opioid, will eliminate the symptoms and signs of withdrawal, reduce cravings, and block the euphoric effects should supplemental opioids be used. The long half-life and predictable dosing prevents erratic opioid levels in the fetus, and is associated with a longer duration of pregnancy and improved fetal growth. As the pregnancy progresses, methadone is metabolized more rapidly and higher
doses are required. Although early reports suggested that the dose of methadone correlated with the incidence and severity of neonatal withdrawal symptoms, recent evidence does not demonstrate such a relationship. It is well accepted that lowering the dose during pregnancy may lead to increased illicit drug use, thus exposing the mother and fetus to more harm. Infants born to women on methadone tend to exhibit more severe and delayed withdrawal symptoms, when compared with those exposed to short-acting opioids, such as heroin. Buprenorphine, a partial opioid agonist, has recently been approved by the United States Food and Drug Administration (FDA) for the treatment of opioid addiction in an outpatient office setting. Although not yet approved for use in pregnancy, early evidence suggests that buprenorphine is associated with a decreased incidence of neonatal withdrawal when compared with methadone.

In addition to the concern regarding withdrawal, the prevalence of hepatitis B, hepatitis C, and human immunodeficiency virus (HIV) is elevated in pregnant addicts, primarily due to needle sharing and unsafe sexual practices. Women should be screened for these infections, and in the case of HIV infection, treatment should be initiated.

The management of addiction in pregnancy is highly complex, and attention must be focused not only on medication, but also on the complicated psychological and social needs of these women. A high number of these women have a history of domestic violence, are poorly educated, financially constrained, and have poor relationships with partners who may also be substance abusers. They have dysfunctional families, with a high prevalence of substance abuse and alcoholism. Many of these women have comorbid psychiatric conditions, most commonly depression and bipolar disorder; all of them suffer from low self-esteem.

The preponderance of cases of neonatal abstinence syndrome is due to in utero opioid exposure. The newborn with opioid withdrawal presents with central nervous system excitability, vasomotor signs, and gastrointestinal symptoms (Box 38.1). The timing of onset of symptoms varies; however, infants exposed to heroin or other short-acting opiates typically will present within the first 48 to 72 hours. Those exposed to methadone will often present later, usually within the first 7 days.

The infant is assessed using a standardized scoring system, such as the Finnegan Neonatal Abstinence Scoring System (Fig. 38.1). This tool assesses 21 symptoms and signs. Infants with scores of 8 or greater require more intensive observation and potential pharmacologic treatment. These scores quantify the severity of symptoms and aid in the initiation and tapering of medications. Other scoring systems are available; some of these are simpler to use and may be more applicable to a well baby nursery or outpatient setting.

A thorough maternal history is crucial, including any illicit or prescribed drug intake, tobacco exposure, and alcohol intake. Newborn urine and meconium toxicology screens may aid in the diagnosis. Urine testing generally reflects drug exposure within several days, depending upon the drug. The results of urine testing are rapidly available; however, a high false negative rate is possible, given the rapid clearance of most drugs and the difficulty in obtaining sufficient urine from a newborn in the first day of life. Meconium testing offers the advantage of assessing drug exposure during the previous several months. However, meconium test results frequently are not available for several days, at which time the infant may have been discharged. Testing of human hair for drugs of abuse has the advantage of a wider window for testing, given hair’s slow growth rate. However, due to the technical complexity of the testing, it has only limited availability and applicability.