In general, pregnant patients are advised to discontinue all medications because drug effects on the fetus are often unknown.
1. Opioids During Pregnancy
Pregnant patients with CNCP on LTOT should be tapered to the lowest effective dose and discontinued if possible. Slow tapering is essential, as opioid withdrawal can cause uterine smooth muscle irritability, and is associated with premature labour and spontaneous abortion.
- If the patient has CNCP and is also addicted to prescription opioids, methadone treatment is recommended.
- During pregnancy and lactation:
- Tramadol is not recommended
- Safety of fentanyl has not been established.
- Where feasible, the treating physician should consider seeking consultation with a physician with expertise in pain, addictions, and pregnancy.
2. Delivery and Postpartum Cautions
Babies born to mothers who used daily opioids during their pregnancy should be delivered in a hospital with appropriate resources to deliver and care for the infant postpartum.
2.1 Neonatal Abstinence Syndrome (NAS)
Regular opioid use for CNCP during pregnancy is associated with a neonatal abstinence syndrome. These babies should be delivered in a hospital prepared to identify and treat the syndrome. NAS:
- usually begins 1–3 days after delivery, and can last for several weeks
- is characterized by poor feeding, irritability, sweating, and vomiting
- has a clinical presentation similar to other neonatal illnesses such as sepsis, hypoglycemia, and hypocalcemia
- is treated with comfort measures and with small doses of morphine,
- has no long-term sequelae.
2.2 Codeine and Breast Feeding
Some women rapidly metabolize codeine to morphine, placing the neonate at risk for fatal opioid toxicity.
- If prescribing codeine for postoperative pain for women who are breast feeding:
- Use small doses and limit the prescription to four days supply.
- Advise the mother to:
- Watch for signs of CNS depression in the baby, e.g., poor feeding and limpness
- Contact a physician if she notes any signs of opioid toxicity (e.g., sedation); this should prompt an urgent assessment of the baby.
- NSAIDS and acetaminophen-oxycodone medications are alternatives to codeine.
R19. Summary of Peer-Reviewed Evidence
1. There is evidence that regular, scheduled opioid use for CNCP during pregnancy is associated with a neonatal abstinence syndrome.
In a study on 13 pregnant women on opioids for chronic pain, 5 of the neonates had neonatal abstinence syndrome (Hadi 2006).
2. Codeine use in breast-feeding women has been associated with fatal opioid toxicity in the neonate.
Codeine is converted to morphine by the cytochrome P450 system. Some patients are rapid converters, resulting in accumulation of morphine in the breast milk (Madadi 2008). There have been several case reports of neonatal toxicity due to morphine accumulation. The key clinical features were: for the baby, not waking up to feed and limpness; and for the mother, signs of sedation and other signs of toxicity. Symptoms were worse by the fourth day (Madadi 2009).
3. Pregnant women addicted to opioids have improved obstetrical and neonatal outcomes when on methadone treatment.
A number of studies have demonstrated that methadone treatment reduces the risk of premature labour, low birth weight and neonatal mortality in heroin-dependent pregnant women (Blinick 1976, Kaltenbach 1998, Kandall 1999, Wang 1999).