THE CASE
We were treating a 23-year-old woman in our clinic for opioid dependence. She had begun using hydrocodone/acetaminophen, oxycodone, and heroin at age 17. Her parents and relatives had a history of alcohol and drug addiction and her brother had died from a heroin overdose.
The patient was taking buprenorphine/naloxone 12 mg/3 mg daily. She attended weekly counseling sessions at a community outreach center. We explained to her the potentially dangerous effects of buprenorphine/naloxone. Urine toxicology was negative for substances other than buprenorphine/naloxone.
Over 8 months, our patient gained 33 pounds and began wearing loose clothing to her appointments. When we asked her about it, she said that she had been “eating more bagels” lately.
What the patient wasn’t telling us was that she was pregnant. (We learned of her pregnancy only after she delivered.) In addition, she didn’t disclose to her obstetrician (OB) that she was taking buprenorphine/naloxone until she was nearly full term. At that point, the OB consulted maternal fetal medicine, and the buprenorphine/naloxone was continued through delivery. The patient had an uncomplicated spontaneous vaginal delivery of an 8.19 lb girl with an APGAR score of 8 at 1 minute and 8 again at 5 minutes.
Concerned about neonatal abstinence syndrome (NAS), which is characterized by tremors, increased body tone, feeding intolerance, vomiting, sweating, and fever, the healthcare team used the NAS scoring system to assess the newborn’s need for pharmacologic therapy. The newborn’s score at birth was 16/45. It then dropped to 11/45 indicating that she was experiencing mild withdrawal, but her symptoms—grunting, tachycardia, increased tone, tremors, irritability, and sweating—suggested she was experiencing severe withdrawal. The infant remained hospitalized for 29 days and received oral morphine titrated to her NAS score. The drug regimen for treatment/tapering was oral morphine given at 0.1 mg/kg/dose every 4 hours. This dose was lowered by 10% each time her NAS score was <8. At discharge, the infant’s NAS score had decreased to 3/45.
After discharge, the mother admitted to us that she concealed her pregnancy because she was afraid of being placed on methadone. She said she didn’t want to have to go to a clinic to receive the medication.
Continued good health. The child has since reached all of her developmental milestones appropriately and has normal height and weight.
DISCUSSION
Opioid abuse is an increasing cause of morbidity and mortality. In the United States, the number of deaths from opioid overdose is approaching that of motor vehicle accidents: approximately 100 deaths a day.1
The use of opioids by a pregnant woman can cause intrauterine growth retardation and preterm delivery.2 It also can result in withdrawal symptoms in the newborn,3 necessitating treatment guided by the NAS score. This score takes into consideration the metabolic, respiratory, central nervous system, and gastrointestinal symptoms of the infant at specified time intervals.4
Treatment options. For nonpregnant patients, opioid dependence typically is treated with methadone, an opioid agonist or buprenorphine, a partial opioid agonist; buprenorphine usually is prescribed as a combination medication that also contains naloxone, an opioid antagonist.
While methadone must be prescribed through licensed clinics, physicians meeting specific qualifications can prescribe buprenorphine or buprenorphine/naloxone in the office setting.5 Studies have supported the effectiveness of buprenorphine, alone or in combination with naloxone, in discouraging illicit opioid use.6-8
When the patient is pregnant… Methadone is the current standard of care for opioid-dependent patients who become pregnant.9 Buprenorphine/naloxone is currently a US Food and Drug Administration category C drug. However, recent studies have demonstrated the safety of buprenorphine without naloxone during pregnancy.10,11
The incidence and severity of NAS following treatment with buprenorphine is less than or comparable to methadone maintenance.10,11 The NAS score of 11 recorded in our patient’s case was comparable to those reported by Jones et al,9 who found neonates of women on buprenorphine had an average maximum NAS score of 11 and those on methadone had a maximum of 12.8.
Higher birth weights have been found for infants in the buprenorphine group. One study noted a mean birth weight of 6.48 lb in a methadone group vs 7.17 lb in a buprenorphine group, a statistically significant difference.11 The birth weight of our patient’s daughter (8.19 lb) was higher than those reported in studies of women receiving buprenorphine and methadone.11,12
Hospital stays were shorter for neonates exposed to buprenorphine when compared to methadone.12 When methadone was used as maintenance therapy their hospital stays were between 8.1 and 19.7 days. On average, buprenorphine-exposed neonates were hospitalized between 6.8 and 10 days.9,11,12
THE TAKEAWAY
Physicians who prescribe or care for women who receive buprenorphine need to remain alert for the possibility of pregnancy. Assess your patient’s weight at each appointment. If you suspect she has become pregnant, address the issue with the patient and obtain consent for a pregnancy test. Although buprenorphine is a category C drug, patients who become pregnant should be made aware that several studies have found that buprenorphine can be used safely and effectively during pregnancy9-12 and it may be an option to continue the medication through delivery.