[Buprenorphine and pregnancy. Analysis of 24 cases]

A Swedish Population-based Study of Adverse Birth Outcomes among Pregnant Women Treated with Buprenorphine or Methadone: Preliminary Findings

BACKGROUND

Untreated opioid dependence in pregnant women is associated with adverse birth outcomes. Buprenorphine and methadone are options for opioid agonist medication-assisted treatment during pregnancy.

OBJECTIVE

The aim of this study was to describe adverse birth outcomes observed with buprenorphine or methadone treatment compared to the general population in Sweden.

METHODS

Pregnant women and their corresponding births during 2005–2011 were identified in the Swedish Medical Birth Register. Data on stillbirth, neonatal/infant death, mode of delivery, gestational age at birth, Apgar score, growth outcomes, neonatal abstinence syndrome, and congenital malformations were examined. Frequencies were compared using two-sided Fisher’s exact tests. Unadjusted estimates of birth outcomes for women treated with buprenorphine or methadone were compared to the registered general population.

RESULTS

A total of 746,257 pregnancies among 538,178 unique women resulted in 746,485 live births. Among the 194 women treated with buprenorphine (N = 176) or methadone (N = 52), no stillbirths or neonatal/infant deaths occurred. Neonatal abstinence syndrome developed in 23.3% and 38.5% of infants born to mothers treated with buprenorphine and methadone, respectively. The frequency of the selected adverse birth outcomes assessed in women treated with buprenorphine as compared to the general population was not significantly different. However, a significantly higher frequency of preterm birth and congenital malformations was observed in women treated with methadone as compared to the general population. Compared with the general population, methadone-treated women were significantly older than buprenorphine-treated women, and both treatment groups began prenatal care later, were more likely to smoke cigarettes, and did not cohabitate with the baby’s father.

CONCLUSIONS

An increased frequency of the selected adverse birth outcomes was not observed with buprenorphine treatment during pregnancy. Twofold increased frequency of preterm birth [2.21 (1.11, 4,41)] and congenital malformations [2.05 (1.08, 3.87)] was observed in the methadone group, which may be partly explained by older average maternal age and differences in other measured and unmeasured confounders.

Efficacy of clonidine versus phenobarbital in reducing neonatal morphine sulfate therapy days for neonatal abstinence syndrome. A prospective randomized clinical trial

OBJECTIVE

To compare the efficacy of clonidine versus phenobarbital in reducing morphine sulfate treatment days for neonatal abstinence syndrome (NAS).

STUDY DESIGN

Prospective, non-blinded, block randomized trial at a single level III NICU (Neonatal Intensive Care Unit). Eligible infants were treated with a combination of medications as per protocol. Primary outcome was treatment days with morphine sulfate. Secondary outcomes were the mean total morphine sulfate dose, outpatient phenobarbital days, adverse events and treatment failures.

RESULTS

A total of 82 infants were eligible, of which 68 were randomized with 34 infants in each study group. Adjusting for covariates phenobarbital as compared with clonidine had shorter morphine sulfate treatment days (-4.6, 95% confidence interval (CI): -0.3, -8.9; P=0.037) with no difference in average morphine sulfate total dose (1.1 mg kg(-1), 95% CI: -0.1, 2.4; P=0.069). Post-discharge phenobarbital was continued for an average of 3.8 months (range 1 to 8 months). No other significant differences were noted.

CONCLUSION

Phenobarbital as adjunct had clinically nonsignificant shorter inpatient but significant overall longer therapy time as compared with clonidine.

Perinatal outcomes of Australian buprenorphine-exposed mothers and their newborn infants

AIM

To determine the short-term outcomes of Australian buprenorphine-exposed mother/infant dyads.

METHODS

Retrospective record review of drug-exposed mothers and infants in Australia. Groups were based on drug exposure: buprenorphine (55, 3.8%), non-buprenorphine opiates (O, 686, 48.6%) and non-opiates (NO, 671, 47.5%).

RESULTS

More than 30% of buprenorphine mothers continued to use heroin (21, 38%) and benzodiazepines (16, 29%). They were more likely to have child at risk concerns (29, 52.7%, P = 0.019) and have previous children placed in out-of-home care (9, 16.3%, P = 049). Buprenorphine babies were less likely to be preterm (16% vs. 25% (O), P = 0.001 and 23% (NO), P = 0.004) and had higher birthweights (median: 3165 g vs. 2842.5 g (O), P < 0.001 and 2900 g (NO), P = 0.004). Buprenorphine and non-buprenorphine opioid babies had similar maximum Finnegan scores (median 10 vs. 11(O), P = 0.144). The number of babies needing abstinence treatment (45% vs. 51% (O), P = 0.411) and length of hospital stay (median days 9 vs. 11(O), P = 0.067) were similar, but buprenorphine infants required lower maximum morphine doses (mg/kg/day) (median 0.4 mg vs. 0.5 mg (O), P = 0.009).

CONCLUSIONS

Short-term medical outcomes of infants of buprenorphine-using mothers are similar to those of non-buprenorphine opiate-using mothers, but interpretation of these results is confounded by the high rates of polydrug exposure in the buprenorphine group. This and other social concerns noted in buprenorphine mothers and infants warrant further study.

Buprenorphine treatment of opioid-dependent pregnant women: a comprehensive review

AIMS

This paper reviews the published literature regarding outcomes following maternal treatment with buprenorphine in five areas: maternal efficacy, fetal effects, neonatal effects, effects on breast milk and longer-term developmental effects.

METHODS

Within each outcome area, findings are summarized first for the three randomized clinical trials and then for the 44 non-randomized studies (i.e. prospective studies, case reports and series and retrospective chart reviews), only 28 of which involve independent samples.

RESULTS

Results indicate that maternal treatment with buprenorphine has comparable efficacy to methadone, although difficulties may exist with current buprenorphine induction methods. The available fetal data suggest buprenorphine results in less physiological suppression of fetal heart rate and movements than methadone. Regarding neonatal effects, perhaps the single definitive conclusion is that prenatal buprenorphine treatment results in a clinically significant less severe neonatal abstinence syndrome (NAS) than treatment with methadone. The limited research suggests that, like methadone, buprenorphine is compatible with breastfeeding. Data available thus far suggest that there are no deleterious effects of in utero buprenorphine exposure on infant development.

CONCLUSIONS

While buprenorphine produces a less severe neonatal abstinence syndrome than methadone, both methadone and buprenorphine are important parts of a complete comprehensive treatment approach for opioid-dependent pregnant women.

Buprenorphine and methadone treatment of opiate dependence during pregnancy: comparison of fetal growth and neonatal outcomes in two consecutive case series

AIM

To compare the effects of fetal buprenorphine and methadone exposure during maintenance treatment of pregnant heroin dependent subjects.

DESIGN AND SETTING

A population based comparison of consecutive, prospectively followed buprenorphine-exposed pregnancies in Stockholm County, Sweden, to retrospectively analyzed consecutive methadone-exposed pregnancies.

PARTICIPANTS

All 47 pregnancies in 39 women with opiate dependence and buprenorphine maintenance treatment 2001-2006, and all 35 methadone-exposed pregnancies (26 women) 1982-2006 in Stockholm County.

MEASUREMENTS

Intrauterine growth, birth outcome, malformations, neonatal adaptation, withdrawal syndrome and infant mortality.

FINDINGS

Buprenorphine-exposed pregnancies resulted in 47 uneventful live births (2 twin pairs), 1 stillbirth (for which no explanation was found) and 1 miscarriage. The birth weight of the infants was normal. Neonatal abstinence syndrome (NAS) occurred in 19 cases (40.4%), the majority mild in nature and only 7 (14.9%) needing withdrawal treatment. Compared to 35 infants born after intrauterine methadone exposure at the same hospital since 1982 (77.8% of them exhibiting NAS and 52.8% needing withdrawal treatment), there were significant advantages with buprenorphine treatment: birth weight was higher, due to longer gestation. Incidence of NAS of any intensity, as well as incidence of NAS that required pharmacological treatment was lower, while length of hospital stay was shorter. When buprenorphine treatment started pre-conception, NAS at any level was significantly less frequent than in subjects with post-conception initiated treatment (7/27, 26%; 12/20, 60%, respectively).

CONCLUSIONS

Data from this non-randomized comparison suggest that buprenorphine may offer advantages for treatment of opiate dependence during pregnancy.

Opioid dependence and pregnancy

PURPOSE OF REVIEW

The management of opioid dependence during pregnancy has received considerable attention over the past three decades. Recent peer-reviewed literature in the fields of pregnancy and opioid dependence and neonatal abstinence syndrome has been evaluated and discussed.

RECENT FINDINGS

Pregnant opioid-dependent women must be carefully managed to minimize harm to the fetus; therefore, standardized care for maternal health is required. In a multidisciplinary care system opioid maintenance therapy is the recommended treatment approach during pregnancy. Equivalent attention must be given to the treatment of neonatal abstinence syndrome, which occurs in 55-94% of neonates after intrauterine opioid exposure with a 60% likelihood of requiring treatment; heterogeneous rating scales as well as heterogeneous treatment approaches are often responsible for extended hospital stays.

SUMMARY

Interpretation of available literature is confounded by several methodological flaws. In general, there is still a lack of evidence-based study designs for pharmacological treatment of these patients as well as neonatal abstinence syndrome.

Un suivi multidisciplinaire et un soutien psychosocial diminuent les complications de la dépendance aux opiacés chez les femmes enceintes

PURPOSE

Drug abuse during pregnancy is an important public health problem. Montpellier University Hospital established a center for addiction and pregnancy in 1997 to provide multidisciplinary prenatal care aimed at reducing maternal and fetal risks during pregnancy and afterwards. This study assesses the trends in drug-taking behavior and pregnancy outcome among women receiving this prenatal care.

METHODS

This exploratory prospective study examined participants in this program during its first 5 years (1997-2002). Women were included if they had been: pregnant, addicted to opiates, enrolled in the program for at least 15 days, and if their delivery took place at Montpellier Hospital. We recorded how often they came to prenatal care, drug-taking behavior, social and economic level, and obstetrical and neonatal outcomes.

RESULTS

The study included 114 women. Those receiving drug substitution at the onset of pregnancy mainly saw general practitioners (64/89 at the beginning of pregnancy), who most often prescribed buprenorphine (70/105 at the end of pregnancy). More than two thirds of patients (n=78) abused several substances. Heroine abuse decreased (p<0.01) over pregnancy, and social and economic level rose (p<0.001). Mean gestational age at delivery was 38.5 weeks. Neonatal withdrawal syndrome remained an important problem and required treatment in 89 infants (78%). No mothers abandoned their infant.

CONCLUSION

Multidisciplinary prenatal care with medical, social, and psychological support can decrease opiate abusers' risks during pregnancy even when the drug treatment program is essentially unsupervised.

Prospective multicenter observational study of 260 infants born to 259 opiate-dependent mothers on methadone or high-dose buprenophine substitution

Specialized prenatal care and substitution programs improve the perinatal prognoses of pregnant drug-abusers and their infants. Although methadone is well documented, little is known about high-dose buprenorphine (HDB). This prospective, multicenter (n = 35) observational study included 259 women on maintenance during pregnancy: 39% on methadone and 61% on HDB. Major findings were: 46% of them received good prenatal care; 62% had peridural analgesia; 12.3% delivered prematurely (<37 weeks); mean gestational age, 38.6 weeks; mean birth weight, 2822g. Three-quarters of the newborns developed neonatal abstinence syndrome (NAS) beginning at a mean age of 40h, with the mean maximum Lipsitz score of 9.1 at 72 h; half of them were treated, mainly with morphine hydrochloride. No baby died. Newborns were discharged with their mothers (96%) or placed in foster care (4%). Comparing methadone with HDB, respectively, mean age at the maximum Lipsitz score was 81 h versus 66 h (P = 0.066). The perinatal medical and social prognoses for these 259 drug addicts and their infants appeared to be improved by specialized prenatal care and was similar for methadone or BHD substitution during pregnancy.

Buprenorphine in pregnant opioid-dependent women: first results of a prospective study

AIM

To report results on the prospective follow-up of 34 pregnant women exposed to buprenorphine maintenance for opiate dependence.

DESIGN AND SETTING

Prospective multicentre study: all pregnant women receiving buprenorphine as maintenance therapy were included as early as possible during their pregnancy.

PARTICIPANTS

The pregnant women were recruited from opiate maintenance therapy centres, general practitioner-networks involved in addiction, maternity hospitals and centres for drug information during pregnancy.

MEASUREMENTS

Women: drugs and medications consumed, medical and obstetrical events; offspring: withdrawal syndrome, malformation, neonatal disease.

FINDINGS

The buprenorphine-exposed pregnancies resulted in 31 live births, one stillbirth, one spontaneous abortion and one voluntary termination. A neonatal withdrawal syndrome was observed in 13 cases (41.9%) and eight of these babies required opiate treatment. Two neonates had a malformation: a premature ductus arteriosus stricture and a tragus appendix.

CONCLUSION

Taken together with other prospective studies, no alarming results were observed concerning pregnancy outcomes. However, further data from the comparative prospective study are required to determine whether buprenorphine can be considered as a good alternative to methadone treatment in pregnant women.

Buprenorphine withdrawal syndrome in newborns: a report of 13 cases

AIMS

To assess neonatal abstinence syndrome (NAS) and neurodevelopmental outcome in infants born to addicted mothers under buprenorphine substitution therapy.

SETTING

District general hospital, Angoulême, France.

METHODS

Retrospective case records study of infants admitted to the neonatal intensive care unit (NICU) and/or special care baby unit (SCBU) from January 1994 to December 2000 for surveillance and/or treatment of buprenorphine NAS.

RESULTS

Thirteen infants were born to addicted mothers under buprenorphine maintenance therapy during the study period. Eight were male and five were female; mean birth term and weight were 39 weeks gestation and 3000 g, respectively. Apgar scores were within normal limits; four infants were small for gestational age, none was dysmorphologic and none was extracted for fetal distress. NAS occurred in 11 cases (85%) and required treatment in 10 cases. Morphine chlorhydrate 0.5 mg/kg/day was administered in divided doses to seven children and gave better results than paregoric alone or in combination with diazepam. Upon follow-up, seven children presented transient lower limbs hypertonia, jerky movements and jitteriness that lasted 3-9 months. The overall milestones acquisitions were within normal limits.

CONCLUSION

Buprenorphine substitution seems to be safe during pregnancy, and has had no teratogenic effects reported to date. It induces NAS of variable intensity that is less prolonged in comparison to methadone; the neurodevelopmental outcome of exposed children is normal in the majority of cases, although some presented with transient motor abnormalities that resolved completely in 85% of those recruited to our study.

Drug abuse's smallest victims: in utero drug exposure

The social and economic impact of drug use on our global population continues to increase leaving no geographical, social or cultural group untouched. The National Institute on Drug Abuse (NIDA), in one of the few large surveys of maternal abuse, found that 5.5% of mothers reported taking an illicit substance during gestation. These figures certainly are underestimates due to the stigma of drug use during pregnancy and the accompanying legal, ethical and economic issues. Although drugs of choice and routes of administration vary by country, exposure of our most valuable resource, our children, to the developmental effects of drugs is an enormous problem. In utero drug exposure can have a severe impact not only on the development of the fetus, but also on the child during later stages of life. More than 75% of infants exposed to drugs have major medical problems as compared to 27% of unexposed infants. The cost of treating drug-affected infants was twice the cost of non-affected infants. Obstetrical complications including placental insufficiency, miscarriage, intrauterine death, and increased incidence of infectious and sexually-transmitted diseases are higher in the drug-abusing mother. Treatment for pregnant addicts should be a high priority for our governments. Increased awareness and improvement in our understanding of drug abuse in the medical, legal and social realms will enable us to reduce the barriers to treatment for this important population.Accurate identification of in utero drug exposure has important implications for the care of the mother and child, but can raise difficult legal issues. Society discourages prenatal care with the infliction of harsh criminal penalties. Maternal drug use during pregnancy can be monitored with urine, sweat, oral fluid and/or hair testing. Detection of in utero drug exposure has traditionally been accomplished through urine testing; however, the window of detection is short, reflecting drug use for only a few days before delivery. Monitoring exposure through testing of alternative matrices, such as neonatal meconium and hair, offers advantages including non-invasive collection and detection earlier in gestation. There are many unresolved issues in monitoring in utero drug exposure that urgently require research. These can be divided into research to definitively differentiate drug exposed and non-drug-exposed fetuses, determine the most efficient methods to routinely monitor women's drug use, and determine how these drug test results relate to neonatal and maternal outcomes. Research in this area is difficult and expensive to perform, but necessary to assess accurately drug effects on the fetus. By increasing our understanding of the physiological, biochemical and behavioral effects of gestational drug exposure, we may ultimately provide solutions for better drug prevention, treatment and a reduction in the number of drug-exposed children.

Buprenorphine treatment of pregnant opioid--dependent women: maternal and neonatal outcomes

This open-label prospective study examined maternal and neonatal safety and efficacy outcome measures during and following prenatal buprenorphine exposure. Three opioid-dependent pregnant women received 8 or 12 mg sublingual buprenorphine tablets daily for 15-16 weeks prior to delivery. Results showed that buprenorphine in combination with comprehensive prenatal care was safe and effective in these women. Prenatal exposure to buprenorphine resulted in normal birth outcomes, a mean of 4.33 days (minimum possible=4) hospitalization, and a 'relatively mild' neonatal abstinence syndrome comprised primarily of tremors (disturbed), hyperactive moro and shortened sleep after feeding. The infants required no pharmacological treatment. Onset of neonatal abstinence signs occurred within the first 12 h after birth, peaked by 72 h and returned to below pre-12 h levels by 120 h. It is concluded that buprenorphine has potential utility for the treatment of pregnant opioid-dependent women.