- No evidence of fetal abnormalities
- Methadone provides pharmacological / physiological stability for the developing fetus at adequate doses for opioid dependent pregnant women
- Dose changes should be made using the same principles as in non-pregnant patients
- Pregnant patients may need an increase methadone dose especially in the third trimester
- Non-dose related neonatal withdrawal is likely but treatable
- Breast feeding should be encouraged unless otherwise contraindicated
Effects of Neonatal Outcome
Infants prenatally exposed to opioids have a high incidence of neonatal abstinence syndrome (NAS), characterized by hyperactivity of the central and autonomic nervous systems that is reflected in changes in the gastrointestinal tract and respiratory system (Kaltenbach et al. 1998). Withdrawal symptoms may begin from minutes or hours after birth to 2 weeks later, but most appear within 72 hours. Preterm infants usually have milder symptoms and delayed onset. Many factors influence NAS onset, including the types of substances used by mothers, timing and dosage of methadone before delivery, characteristics of labor, type and amount of anesthesia or analgesic during labor, infant maturity and nutrition, metabolic rate of the infant’s liver, and presence of intrinsic disease in infants. NAS may be mild and transient, delayed in onset or incremental in severity, or biphasic in its course, including acute neonatal withdrawal signs followed by improvement and then onset of subacute withdrawal (Kaltenbach et al. 1998). Although NAS can be more severe or prolonged with methadone than heroin because of methadone’s longer half-life, with appropriate pharmacotherapy, NAS can be treated satisfactorily without any severe neonatal effects.
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