Opioids

From: Exposure to Psychotropic Medications and Other Substances during Pregnancy and Lactation: A Handbook for Health Care Providers

On this page:

Summary and recommendations
Fetal effects
Neonatal effects
Long-term effects on the child
Breastfeeding
Withdrawal effects on the mother

Examples

Codeine (in Tylenol 3), heroin, hydrocodone (Tussionex), hydromorphone (Dilaudid), meperidine (Demerol), methadone, morphine (MS Contin, Statex), oxycodone (Percodan, Percocet, OxyContin)

Street names

Heroin: junk, H, smack, horse, skag, dope (also used to refer to cannabis), shit

Morphine: M, morph, Miss Emma

Methadone: juice, meth (also used to refer to methamphetamine)

Hydromorphone (Dilaudid): juice

Oxycodone: oxy, OC, percs

Opioids are used therapeutically for the treatment of pain and recreationally for their psychogenic qualities. Opioids can also be used to control coughs and diarrhea, or for treating addiction (i.e., to other opioids). While these drugs occur naturally (e.g., morphine), some are produced semi-synthetically (e.g., heroin) or synthetically (e.g., methadone).

All opioids produce morphine-like effects; however, since they also produce feelings of euphoria, they can be prone to abuse. Opioids are taken orally, injected or smoked. Their use can range from occasional (e.g., over-the-counter codeine) to daily, prescribed use to various forms of abuse. Injection opioid use with unsterile needles increases the risk of serious infection (e.g., hepatitis, HIV) in both the mother and the fetus or baby.

Summary and Recommendations

Women who take moderate doses of prescribed opioids (e.g., Tylenol 3, three to four tablets daily), who are not psychologically or physically dependent on the drug and who become pregnant may continue with the medication, but at the lowest effective dose possible.
If tapering is considered, it should be the woman’s choice and she should be under close supervision. Dose reductions should be limited to no more than 10 per cent of the total dose per week. Tapering should start in the second trimester (i.e., 14 to 28 weeks) to reduce risk of spontaneous abortion or preterm labour. In addition, a pain expert and addiction medicine specialist may provide helpful support during pregnancy.
Methadone is safer to use during pregnancy than are illegal opioids, and is the standard of care for opioid dependence. Methadone maintenance treatment reduces opioid withdrawal and thus improves maternal health and compliance with prenatal care, which in turn reduces fetal and neonatal complications. Only physicians experienced in methadone use should prescribe the drug, since dose requirements must be closely monitored and may change during the pregnancy.
Neonates of mothers treated with methadone should be observed in hospital for symptoms of withdrawal for at least four to five days.
Women who take methadone can safely breastfeed their babies; very small amounts of methadone are present in breast milk.¹
Suggestions for prescribing codeine to women who are breastfeeding include prescribing for two to three days only to prevent neonatal accumulation of morphine, counselling parents to watch for signs of overdose in their babies and following up closely with breastfed infants who have symptoms such as excessive drowsiness.²

Fetal effects

Opioid withdrawal in the third trimester can lead to premature labour.³

Major malformations

Opioids (including heroin) are not linked to any major malformations.^4,5

In the late 1970s and early 1980s, a few studies suggested that opioid abuse in the first and second trimesters may slightly increase the risk of some malformations (e.g., inguinal hernias, and cleft lip and palate). However, study confounders—such as the mother’s use of multiple drugs, maternal disease, lack of prenatal care, poverty and malnutrition—make it impossible to form definite conclusions about this increased risk from these early studies.^6–8 More recent studies that control for these confounders have not found an increased risk of major malformations.⁹

Spontaneous abortion

Occasional prescribed use of opioids is generally considered safe. However, when used regularly (e.g., on a daily basis), opioids can increase the risk of spontaneous abortion.¹⁰ In addition, opioid withdrawal can trigger uterine contractions in the first trimester that can lead to spontaneous abortion.³

Neonatal effects

In general, a neonate experiences withdrawal only when the mother used opioids regularly during pregnancy. Forty to 60 per cent of infants born to women using heroin, and up to 85 per cent of those born to mothers taking methadone, experience withdrawal.³

In a newborn, withdrawal is difficult to diagnose if the mother does not disclose her opioid use because other newborn conditions (e.g., hypoglycemia) have similar symptoms. Withdrawal usually begins shortly after birth, typically within 24 hours but possibly up to two weeks later, depending on the half-life of the opioid. Withdrawal can last for several weeks, and symptoms include difficulty breathing upon birth and extreme drowsiness. Poor feeding, irritability, sweating, tremors, vomiting and diarrhea may also occur, while seizures and death have been reported in severe, untreated withdrawal cases. Babies undergoing opioid withdrawal commonly experience a more severe withdrawal if the mother is also taking alcohol or benzodiazepines.

Treatment of the baby’s withdrawal from opioids consists primarily of supportive care and may include the administration of small doses of morphine.

Neonatal withdrawal is not associated with any long-term complications.

Long-term effects on the child

Babies of mothers who use heroin present with some long-term effects. One study found that at three to six years of age, for example, children whose mothers were addicted to heroin were lower in weight and height compared to the control group, and impaired in behavioural, perceptual and organizational abilities compared to the controls.¹¹

Breastfeeding

At therapeutic doses, most opioids (e.g., morphine, meperidine, methadone) are excreted into breast milk in minimal amounts and are, therefore, compatible with breastfeeding.^1,12,13 These levels are generally considered unlikely to prevent withdrawal in neonates, although one study found that there was less need for neonatal abstinence syndrome treatment in breastfed infants than in those fed with formula.¹⁴ This may be due in part to factors related to the breastfeeding itself rather than the opioid in the breast milk.¹⁵

For mothers being treated with methadone, the amount that passes into the milk is small (two to four per cent).¹⁶ In its 1994 guidelines,¹⁷ the American Academy of Pediatrics (AAP) recommended breastfeeding only at maternal doses of 20 milligrams or less. Since then, there have been reports of maternal methadone doses of up to 180 milligrams during breastfeeding without adverse effects.^18–21 The 2001 AAP guidelines eliminated the dose restriction, and methadone is now considered compatible with breastfeeding.²²

Codeine is considered compatible with breastfeeding by most standard references and the AAP,²² but a recent case report has brought this recommendation into question. A baby who had been breastfed by a mother who was taking codeine for postlabour pain died from morphine overdose 13 days after birth.²³ It was later determined that the mother was an ultrarapid metabolizer with the enzyme cytochrome P450 2D6, and produced much more morphine than most mothers would. Thus far, no new recommendations have emerged. Though ultrarapid metabolizers are rare, the frequency of codeine prescriptions postpartum raises concern. Suggestions include prescribing for two to three days only to prevent neonatal accumulation of morphine, counselling parents to watch for signs of overdose in their babies and following up closely with breastfed infants who have symptoms such as excessive drowsiness.²

Withdrawal effects on the mother

Opioid withdrawal symptoms include nausea, vomiting, diarrhea, sweating, myalgias, chills, rhinorrhea, runny eyes and piloerection. Psychological symptoms can include insomnia, anxiety, strong drug cravings and dysphoria.²⁴

Pregnancy-specific opioid withdrawal symptoms include abdominal cramping and uterine irritability, which may lead to an increased risk of spontaneous abortion, preterm labour, fetal hypoxia and fetal death.²⁴

Withdrawal symptoms begin six to 24 hours after the last opioid dose, depending on the opioid’s duration of action. Patients in severe withdrawal may appear anxious and uncomfortable. They may be huddled over, with chills and vomiting. Physical symptoms peak at two to three days, and largely resolve in five to 10 days. Psychological symptoms (e.g., insomnia, anxiety, cravings) may persist for weeks or months.²⁴ Patients typically find the psychological symptoms of opioid withdrawal far more disturbing than the physical withdrawal symptoms.

For adults, the main complications of opioid withdrawal are suicidality and overdose.²⁴ Suicide attempts may occur in settings where a person is unable to obtain relief from the withdrawal experience (e.g., a prison). People who stop using opioids begin to lose their tolerance to the drug within days. As a result, if they relapse and begin taking their usual opioid dose again, they may be at risk for overdose.

References

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