The nation is in the midst of an opioid crisis and the statistics are staggering. The Centers for Disease Control and Prevention (CDC) reports that 2 million Americans are addicted to opioids.1 Opioid use in pregnancy has mirrored the general population, increasing each year.2 The escalation of use in pregnancy has brought a concurrent rise in the rates of infants born with Neonatal Abstinence Syndrome (NAS) and a tragic increase in overdose deaths. Opioid Use Disorder (OUD) is a medical condition characterized by a problematic pattern of opioid use that causes clinically significant impairment or distress (Table 1). It is sometimes referred to as opioid use or dependence or addiction.1 Ob/gyns are on the front lines of this epidemic and have a responsibility to recognize, treat, refer and advocate for the pregnant women with OUD. Understanding the biology, epidemiology, evaluation, and current data regarding effective treatment options during pregnancy is necessary in order to have a framework for treating this complex disease.
Opioids have a powerful effect on the brain - both positive and negative. Opioids are natural or synthetic chemicals that interact with mu receptors on nerve cells in the gastrointestinal tract, spinal cord and the brain, thereby reducing feelings of pain.3 This class of drugs includes the illegal drug heroin, synthetic opioids such as fentanyl, and pain medications available legally by prescription, such as oxycodone, hydrocodone, codeine, morphine, and many others. Although these drugs are generally considered safe when taken for a short time and as prescribed by a physician, the individual response to them varies markedly. Although not completely understood, there is great heterogeneity in mu receptor structure, functional activation and localization within the cells and regions of the brain.4 This diversity may, in part, account for the varied responses seen clinically. In addition, opioids are also known to disrupt the neuronal machinery of the brain-reward center. When in balance, the cells in the ventral tegmental area (VTA) produce dopamine and release it into the nucleus accumbens (NAc), giving rise to feelings of pleasure. Feedback from the prefrontal cortex back to the VTA helps us overcome drives to obtain pleasure through actions that may be unsafe or unwise. However, this feedback has been noted to be dysregulated in individuals who later develop substance use disorders.4
Addiction is a complex brain disorder characterized by compulsive drug seeking despite extremely negative consequences. Repeated exposure to escalating dosages of opioids alters the brain, causing 2 different but interrelated clinical problems: tolerance and dependence.4 Tolerance is characterized by the need to take escalating dosages of a drug to achieve the same effect. Dependence is the susceptibility to withdrawal symptoms in the absence of the drug.
With addiction, this powerful biological effect of opioids is translated into a set of behaviors that are challenging for the individual, family, community and society as the reward center of the brain and drug seeking becomes the dominant and all-consuming focus for the individual.5
The National Institute of Drug Abuse (NIDA) reports that 20% to 30% of patients prescribed opioids for chronic pain misuse them. About 10% of those prescribed opioids for chronic pain will develop OUD. An estimated 5% who misuse prescription opioids will transition to heroin. Of those currently using heroin, 80% started their addiction by misusing prescription opioids.6
OUD and consequent overdose deaths have reached an all-time high.6 In February 2018, the National Institutes of Health reported that 115 deaths occurred daily because of opioid overdose.6 The CDC estimates that 64,070 people living in the United States died from overdoses (all kinds) in 2016, an increase from 52,404 overdose deaths in 2015.7 Fentanyl was the number one cause fueling this dramatic increase and responsible for almost 17,000 deaths.8 Drug overdose is now the leading cause of accidental death (categorized as poisonings at the CDC) in the United States, surpassing motor vehicle crashes in 2011. Although death is a tragic outcome and an important metric, the societal cost is far broader, affecting families, children, the workforce, penal system, healthcare and communities. NIDA estimates that the financial cost is over $600 billion each year.9