Benefit should outweigh risk

AU TGA pregnancy category: C
US FDA pregnancy category: Not assigned

Risk Summary: There are no available data to inform a drug-associated risk for major birth defects and miscarriage with this drug; prolonged use of opioids during pregnancy can result in physical dependence in the neonate.

Comments:
-Women using opioids during pregnancy for medical or nonmedical purposes should be advised of the risk of neonatal abstinence syndrome and ensure that appropriate treatment will be available.
-Neonatal respiratory depression is possible when morphine is used in labor; an opioid antagonist, such as naloxone, must be available for reversal of opioid induced respiratory depression in the neonate.
-Long-acting opioids should not be used during and immediately prior to labor, when short acting analgesics or other analgesic techniques are more appropriate.

In published animal studies, subcutaneous administration during early gestational period produced neural tube defects at 5 and 16 times the human daily dose (HDD) in hamsters and mice, respectively. In rabbits, lower fetal weight and an increased incidence of abortion occurred at 0.4 times the HDD. In humans, published reports have not shown an association with morphine and major birth defects. Opioid analgesics cross the placenta. The use of this drug during labor may cause respiratory depression in the newborn infant. Prolonged use of opioids during pregnancy can result in physical dependence in the neonate and neonatal opioid withdrawal syndrome shortly after birth. The onset, duration, and severity of the condition will vary based on use (duration of use, timing, and amount of last maternal use) and rate of elimination in the newborn. There are no controlled data in human pregnancy.

Chronic use of opioids may cause reduced fertility; it is unknown whether these effects are reversible.

AU TGA pregnancy category C: Drugs which, owing to their pharmacological effects, have caused or may be suspected of causing, harmful effects on the human fetus or neonate without causing malformations. These effects may be reversible. Accompanying texts should be consulted for further details.

US FDA pregnancy category Not Assigned: The US FDA has amended the pregnancy labeling rule for prescription drug products to require labeling that includes a summary of risk, a discussion of the data supporting that summary, and relevant information to help health care providers make prescribing decisions and counsel women about the use of drugs during pregnancy. Pregnancy categories A, B, C, D, and X are being phased out.

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Epidural administration for postcesarean section analgesia has resulted in small amounts of morphine in colostrum and milk; IV or oral doses administered in the immediate postpartum period have resulted in higher milk levels. Administration of pain medication during labor may delay the onset of lactation. Morphine can increase serum prolactin and this increase in serum prolactin is most likely to affect initiation of breastfeeding while not affect a mother whose lactation is established. Once a mother's milk comes in, it is best to provide pain control with a nonnarcotic analgesic and limit maternal use of opioid analgesics to 2 to 3 days at a low dose with close infant monitoring.

Lactation studies have not been conducted with the extended-release morphine products. Breastfeeding is generally not recommended with these products because of the potential for serious adverse reactions, including excess sedation and respiratory depression in the breastfed infant. Withdrawal symptoms can occur in breastfed infants when maternal administration of morphine is stopped, or when breastfeeding is stopped.

Benefit should outweigh risk

Excreted into human milk: Yes

Comments:
-Maternal use of oral narcotics during breastfeeding can cause infant drowsiness, CNS depression, and even death, newborn infants are particularly sensitive to even small doses.
-Monitor breastfed infants closely; a healthcare provide should be contacted immediately if there are any signs of increased sleepiness, difficulty breastfeeding, breathing difficulties, or limpness.

See references