Opioids in pregnancy and neonatal abstinence syndrome
Section snippets
Prevalence of opiate use in pregnancy
Opiate use in the United States has risen dramatically in recent years. In 2012, prescribers wrote 82.5 opioid prescriptions and 37.6 benzodiazepine prescriptions per 100 persons, with significant variation observed between states and regions.1 Women of reproductive age have been significantly impacted, with approximately 28% of privately-insured and 39% of Medicaid enrolled women aged 15–44 years filling a prescription for an opioid medication each year between the years 2008–2012.2 Maternal
Maternal agonist treatment for opiate-dependent pregnant women
Maternal opioid-substitution programs have been shown to improve pregnancy outcomes by reducing withdrawal episodes and high-risk drug-seeking behaviors as well as improving compliance with prenatal care. Most of these programs use methadone, which is a full mu-opioid agonist in use since the 1970s.4 The pharmacokinetics of methadone in pregnant women differs from the non-pregnant population and changes significantly throughout pregnancy. For example, the half-life of methadone falls from an
Neonatal abstinence syndrome
NAS is a complex and highly variable condition characterized by central nervous system hyperirritability, autonomic nervous system dysfunction, and gastrointestinal disturbances. Frequently observed features include excessive crying, irritability, poor sleep, increased muscle tone, tremors, excoriations of the skin from excessive movements, hyperthermia, loose stools, yawning, sweating, nasal stuffiness, and sneezing. In addition, seizures can occur in 2–11% of the infants with NAS.16, 17
Treatment
The initial approach to NAS treatment is non-pharmacologic therapy which involves creating a gentle, soothing environment with minimal environmental stimulation for the neonate. Frequent hypercaloric feeds are typically administered to minimize hunger and promote growth. Maternal involvement in the infant’s care is an important component of non-pharmacologic management.16, 24
Pharmacologic treatment is required in the majority of infants with NAS.17 Several treatment approaches are used and no
Long-term follow-up
Adverse neurodevelopmental outcomes have been described in infants/children exposed in utero to opioids. However, there is a paucity of data regarding long-term neurodevelopmental function, as most studies are small and are unable to differentiate the effects of in utero exposures, postnatal treatments, and environmental influences. In general, opioid exposed children more likely to have attention deficit disorders, disruptive behavior, and the need for comprehensive psychiatric referrals.28, 29
Predictive factors
Factors that influence the onset and severity of NAS remain incompletely understood. Potential variables include maternal opiate dose, the specific maintenance agent, concurrent use of other drugs (e.g., nicotine, benzodiazepines, and selective serotonin reuptake inhibitors—SSRIs), gestational age, birth weight, and pharmacogenomics. Outcomes typically evaluated include treatment for NAS, peak NAS score, total dose required for treatment, duration of treatment, and length of hospitalization.
Future directions
As the number of pregnancies affected by maternal opiate dependence continues to rise, work is urgently needed to fill the significant knowledge gaps regarding optimal prenatal and postnatal care of opiate-dependent mothers and neonates. Specific areas of focus should include:
- (1)
Reducing opiate exposure in young women of child-bearing age.
- (2)
Improving maternal treatment programs to reduce the incidence and severity of NAS.
- (3)
Better identifying and treating high-risk neonates through personalized genomic
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