Opioid misuse during pregnancy is dangerous to both the fetus and mother. Despite this, illicit opioid use in pregnant women is on the rise.
According to available data, opioid use disorder (OUD) rates in pregnant women have increased 130% from 2010 to 2017. In addition to this, between 1-2% of women reported misuse of prescription opioid pain relievers in 2019.
In this article, we will cover the risks associated with opioid use, misuse, and OUD during pregnancy. We will also discuss why Medication for Addiction Treatment (MAT) is the best treatment approach and what medications are commonly prescribed.
Neonatal Abstinence Syndrome (NAS) refers to the opioid withdrawal syndrome that occurs in the newborn when the mother has been taking opioids daily or has OUD before giving birth.
When the fetus is exposed to opioids during pregnancy at high doses, it will develop a tolerance to opioids and a susceptibility to withdrawal symptoms when the opioid blood levels drop upon delivery.
NAS is treated in the hospital with supportive care and morphine. Signs of NAS occur within 72 hours after birth and include the following symptoms:
Opioid use disorder is a diagnostic term that helps clinicians identify people whose opioid use has spiraled out of control. Colloquial terms for OUD include “opioid addiction” and “opioid dependency.”
All patients with OUD should seek treatment with MAT throughout their pregnancy to block cravings and prevent relapse. Simply going through detox and getting counseling is not enough since studies consistently show better fetal and maternal outcomes with MAT.
MAT is the standard of care, and methadone and buprenorphine are endorsed for the treatment of pregnant women with OUD by the American College of Obstetricians & Gynecologists (ACOG) and the American Society of Addiction Medicine (ASAM).
There are three primary types of medications used in MAT:
Similar to morphine, fentanyl, and heroin, methadone is a full opioid agonist that activates the opioid receptor. For over half a century, methadone has been used for the treatment of OUD. It is longer-acting than most opioids which means it stabilizes blood levels and prevents withdrawal.
Methadone dispensing during OUD treatment is highly structured, and clinics are required to have special licensing, which minimizes abuse and diversion.
Studies show that methadone treatment of pregnant women with OUD reduces craving, relapse, HIV and hepatitis C infection rates, and legal problems. It also reduces the risk of death by overdose compared to no treatment or psychosocial treatment alone. It also improves perinatal care, reduces NAS risk, and leads to higher gestational age, weight, and head circumferences.
One negative of methadone is that the infant can still experience NAS upon delivery, albeit to a lesser degree than that seen with abused opioids.
Despite this, methadone is still better for pregnant women than detoxification and psychosocial treatment alone. It prevents the repeated cycles of intoxication and withdrawal associated with opioid misuse.
On the other hand, the NAS is worse in infants whose mothers are treated with methadone compared to buprenorphine.
Buprenorphine is a partial agonist at the opioid receptor. Like methadone, it can block cravings and withdrawal symptoms and prevent relapse.
However, buprenorphine has an additional safety advantage over methadone. At higher doses, it has a ceiling effect, meaning the opioid agonist effect doesn’t increase past a certain dose. As a result, it is much harder to overdose on buprenorphine than methadone and other full agonists.
Buprenorphine also stabilizes maternal and fetal levels of opioids and prevents perinatal withdrawal, similar to methadone. It links mothers to perinatal care, reduces infection risk, reduces NAS severity, and improves maternal, pregnancy, fetal, and infant outcomes.
Although NAS can occur upon delivery, it is less severe than the NAS seen with maternal use of illicit opioids or methadone. Other fetal outcomes might be better with buprenorphine compared to methadone, too.
Until recently, Subutex was used in pregnant women almost exclusively because of concerns that naloxone might cross the placenta and cause adverse effects.
However, more recent studies show that very little placental transfer occurs and that Suboxone might be as safe or safer for the fetuses and infants than either methadone or Subutex.
Naltrexone, often given in a monthly injectable form, is the third medication sometimes used to prevent relapse in OUD because it blocks craving and prevents relapse. Unlike buprenorphine and methadone, naltrexone (Vivitrol) is an opioid receptor blocker, not an agonist.
Until recently, naltrexone was not a recommended treatment for pregnant women with OUD, except for those already taking naltrexone for OUD before they got pregnant.
Although still not standard of care, it is increasingly being used off-label for OUD treatment in pregnancy, and more research into its safety and efficacy is underway. So far, rates of adverse effects from naltrexone or Vivitrol compared to methadone or buprenorphine and untreated OUD appear to be similar.
Of the three OUD medication treatments, the only one that should be avoided is no treatment at all. Study after study shows that MAT is better for the mother and the fetus than no MAT, i.e., 12-step programs or counseling alone. Relapse rates without MAT are high, and repeated cycles of withdrawal and intoxication associated with untreated OUD are dangerous.
That said, all three kinds of medications used during MAT can cross the placenta and are considered “Class C” by the FDA. This means that it is still unknown whether the medication has direct adverse effects on the fetus.
Untreated OUD in pregnancy is dangerous, and guidelines encourage all pregnant mothers to take MAT.
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