Opiate addiction in adult offspring through possible imprinting after obstetric treatment

Intrapartum opioid analgesia and childhood neurodevelopmental outcomes among infants born preterm

BACKGROUND

There are concerns regarding neurobehavioral changes in infants exposed to parenteral opioids during labor; however, long-term neurodevelopment remains unstudied.

OBJECTIVE

We aimed to examine the association between parenteral opioids used as labor analgesia and perinatal outcomes and childhood neurodevelopment until 2 years of age among infants born prematurely. We hypothesized that intrapartum exposure to parenteral opioids is associated with impaired neurodevelopment and adverse perinatal outcomes.

STUDY DESIGN

This was a secondary analysis of a multicenter, randomized controlled trial assessing magnesium for the prevention of cerebral palsy in infants at risk for preterm birth. Women delivering a singleton, nonanomalous, live infant before 37 weeks' gestation were considered for inclusion. Women were excluded if they had missing exposure or primary outcome data, were exposed to general anesthesia, or reported use of heroin or unspecified illicit drugs. Women reporting use of nonopioid illicit drugs such as cocaine and marijuana were not excluded. Groups were compared based on exposure or nonexposure to parenteral opioids (intravenous or intramuscular) used as labor analgesia. The primary outcome was any psychomotor or mental developmental delay at 24 months according to the Bayley Scales of Infant Development II. Secondary outcomes were the Bayley Scales of Infant Development II subdomains and adverse perinatal outcomes. Multivariable logistic regression models were performed and adjusted odds ratios with 95% confidence intervals were estimated.

RESULTS

Of the 1404 women included, 535 (38%) received parenteral opioids as labor analgesia. Women receiving parenteral opioids were more likely to be younger, Hispanic, and present with cervical dilation ≥4 cm. Parenteral opioid recipients had lower rates of illicit nonopioid drug or tobacco use, a lower rate of cesarean delivery, lower educational level and were less likely to be undergoing induction. Women receiving parenteral opioids who underwent cesarean delivery were less likely to do so because of a nonreassuring fetal status. In the unadjusted and adjusted analyses, there were no significant differences in the primary outcomes of psychomotor or mental developmental delay at 2 years of age (adjusted odds ratio, 0.96; confidence interval, 0.76-1.20). The only significant difference in secondary outcomes was a shorter O₂ requirement duration in the parenteral opioid group (2 vs 4 days; P=.002).

CONCLUSION

Among a population of preterm infants vulnerable to neurologic impairment, intrapartum exposure to parenteral opioids was not associated with an increased risk for neurodevelopmental delay up to 2 years of age, nor did these infants have worse perinatal outcomes.

A plausible causal relationship between the increased use of fentanyl as an obstetric analgesic and the current opioid epidemic in the US

Drug poisoning deaths have more than doubled in the United States since 2000 with fentanyl and fentanyl analogues primarily responsible for the jump in opioid deaths. Robust data indicate a convincing correlation between the exposure of the fetus to other labor medications (morphine, pethidine hydrochloride, barbiturates, phenobarbitone, meperidine, and secobarbital) and the later addiction of young adults to the same category of drug. We present the hypothesis that this effect is also true of the opioid, fentanyl: there is a causal relationship between the increased popularity of fentanyl as a labor anesthetic in the United States since the 1980's and the current epidemic of fentanyl abuse.

Parenteral opioids for maternal pain management in labour

BACKGROUND

Parenteral opioids (intramuscular and intravenous drugs including patient-controlled analgesia) are used for pain relief in labour in many countries throughout the world. This review is an update of a review first published in 2010.

OBJECTIVES

To assess the effectiveness, safety and acceptability to women of different types, doses and modes of administration of parenteral opioid analgesia in labour. A second objective is to assess the effects of opioids in labour on the baby in terms of safety, condition at birth and early feeding.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (11 May 2017) and reference lists of retrieved studies.

SELECTION CRITERIA

We included randomised controlled trials examining the use of intramuscular or intravenous opioids (including patient-controlled analgesia) for women in labour. Cluster-randomised trials were also eligible for inclusion, although none were identified. We did not include quasi-randomised trials. We looked at studies comparing an opioid with another opioid, placebo, no treatment, other non-pharmacological interventions (transcutaneous electrical nerve stimulation (TENS)) or inhaled analgesia.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. We assessed the quality of each evidence synthesis using the GRADE approach.

MAIN RESULTS

We included 70 studies that compared an opioid with placebo or no treatment, another opioid administered intramuscularly or intravenously or compared with TENS applied to the back. Sixty-one studies involving more than 8000 women contributed data to the review and these studies reported on 34 different comparisons; for many comparisons and outcomes only one study contributed data. All of the studies were conducted in hospital settings, on healthy women with uncomplicated pregnancies at 37 to 42 weeks' gestation. We excluded studies focusing on women with pre-eclampsia or pre-existing conditions or with a compromised fetus. Overall, the evidence was graded as low- or very low-quality regarding the analgesic effect of opioids and satisfaction with analgesia; evidence was downgraded because of study design limitations, and many of the studies were underpowered to detect differences between groups and so effect estimates were imprecise. Due to the large number of different comparisons, it was not possible to present GRADE findings for every comparison.For the comparison of intramuscular pethidine (50 mg/100 mg) versus placebo, no clear differences were found in maternal satisfaction with analgesia measured during labour (number of women satisfied or very satisfied after 30 minutes: 50 women; 1 trial; risk ratio (RR) 7.00, 95% confidence interval (CI) 0.38 to 128.87, very low-quality evidence), or number of women requesting an epidural (50 women; 1 trial; RR 0.50, 95% CI 0.14 to 1.78; very low-quality evidence). Pain scores (reduction in visual analogue scale (VAS) score of at least 40 mm: 50 women; 1 trial; RR 25, 95% CI 1.56 to 400, low-quality evidence) and pain measured in labour (women reporting pain relief to be "good" or "fair" within one hour of administration: 116 women; 1 trial; RR 1.75, 95% CI 1.24 to 2.47, low-quality evidence) were both reduced in the pethidine group, and fewer women requested any additional analgesia (50 women; 1 trial; RR 0.71, 95% CI 0.54 to 0.94, low-quality evidence).There was limited information on adverse effects and harm to women and babies. There were few results that clearly showed that one opioid was more effective than another. Overall, findings indicated that parenteral opioids provided some pain relief and moderate satisfaction with analgesia in labour. Opioid drugs were associated with maternal nausea, vomiting and drowsiness, although different opioid drugs were associated with different adverse effects. There was no clear evidence of adverse effects of opioids on the newborn. We did not have sufficient evidence to assess which opioid drug provided the best pain relief with the least adverse effects.

AUTHORS' CONCLUSIONS

Though most evidence is of low- or very-low quality, for healthy women with an uncomplicated pregnancy who are giving birth at 37 to 42 weeks, parenteral opioids appear to provide some relief from pain in labour but are associated with drowsiness, nausea, and vomiting in the woman. Effects on the newborn are unclear. Maternal satisfaction with opioid analgesia was largely unreported. The review needs to be examined alongside related Cochrane reviews. More research is needed to determine which analgesic intervention is most effective, and provides greatest satisfaction to women with acceptable adverse effects for mothers and their newborn.

Nitrous oxide for the management of labor pain: a systematic review

BACKGROUND

We systematically reviewed evidence addressing the effectiveness of nitrous oxide for the management of labor pain, the influence of nitrous oxide on women's satisfaction with their birth experience and labor pain management, and adverse effects associated with nitrous oxide for labor pain management.

METHODS

We searched the MEDLINE, EMBASE, and Cumulative Index to Nursing and Allied Health Literature (CINAHL) databases for articles published in English. The study population included pregnant women in labor intending a vaginal birth, birth attendees or health care providers who may be exposed to nitrous oxide during labor, and the fetus/neonate.

RESULTS

We identified a total of 58 publications, representing 59 distinct study populations: 2 studies were of good quality, 11 fair, and 46 poor. Inhalation of nitrous oxide provided less effective pain relief than epidural analgesia, but the quality of studies was predominately poor. The heterogeneous outcomes used to assess women's satisfaction with their birth experience and labor pain management made synthesis of studies difficult. Most maternal adverse effects reported in the literature were unpleasant side effects that affect tolerability, such as nausea, vomiting, dizziness, and drowsiness. Apgar scores in newborns whose mothers used nitrous oxide were not significantly different from those of newborns whose mothers used other labor pain management methods or no analgesia. Evidence about occupational harms and exposure was limited.

CONCLUSIONS

The literature addressing nitrous oxide for the management of labor pain includes few studies of good or fair quality. Further research is needed across all of the areas examined: effectiveness, satisfaction, and adverse effects.

Maternally administered sustained-release naltrexone in rats affects offspring neurochemistry and behaviour in adulthood

Naltrexone is not recommended during pregnancy. However, sustained-release naltrexone implant use in humans has resulted in cases of inadvertent foetal exposure. Here, we used clinically relevant dosing to examine the effects of maternally administered sustained-release naltrexone on the rat brain by examining offspring at birth and in adulthood. Maternal treatment (naltrexone or placebo implant) started before conception and ceased during gestation, birth or weaning. Morphometry was assessed in offspring at birth and adulthood. Adult offspring were evaluated for differences in locomotor behaviour (basal and morphine-induced, 10 mg/kg, s.c.) and opioid neurochemistry, propensity to self-administer morphine and cue-induced drug-seeking after abstinence. Blood analysis confirmed offspring exposure to naltrexone during gestation, birth and weaning. Naltrexone exposure increased litter size and reduced offspring birth-weight but did not alter brain morphometry. Compared to placebo, basal motor activity of naltrexone-exposed adult offspring was lower, yet they showed enhanced development of psychomotor sensitization to morphine. Developmental naltrexone exposure was associated with resistance to morphine-induced down-regulation of striatal preproenkephalin mRNA expression in adulthood. Adult offspring also exhibited greater operant responding for morphine and, in addition, cue-induced drug-seeking was enhanced. Collectively, these data show pronounced effects of developmental naltrexone exposure, some of which persist into adulthood, highlighting the need for follow up of humans that were exposed to naltrexone in utero.

Male circumcision: pain, trauma and psychosexual sequelae

Infant male circumcision continues despite growing questions about its medical justification. As usually performed without analgesia or anaesthetic, circumcision is observably painful. It is likely that genital cutting has physical, sexual and psychological consequences too. Some studies link involuntary male circumcision with a range of negative emotions and even post-traumatic stress disorder (PTSD). Some circumcised men have described their current feelings in the language of violation, torture, mutilation and sexual assault. In view of the acute as well as long-term risks from circumcision and the legal liabilities that might arise, it is timely for health professionals and scientists to re-examine the evidence on this issue and participate in the debate about the advisability of this surgical procedure on unconsenting minors.

Parenteral Pethidine for labour pain relief and substance use disorder: 20-year follow-up cohort study in offspring

OBJECTIVE

To determine whether use of intrapartum Pethidine pain analgesia increases the risk for substance use disorder in adult offspring.

DESIGN

Analysis of data from a cohort study.

SETTING

Academic hospital in Leiden, the Netherlands.

PARTICIPANTS

133 cases and 164 control individuals, aged 18-20 years at follow-up.

MAIN OUTCOME MEASURE

Incidence of substance use disorder or use of alcohol and tobacco.

RESULTS

The lifetime use of addictive substances in children exposed to intrapartum Pethidine analgesia was 45% of 133 children versus 48% of 164 not-exposed subjects (adjusted OR=0.79, 95% CI 0.48 to 1.29). Recent use of alcohol, tobacco and hard drugs showed no statistical difference either.

CONCLUSION

Pethidine for labour pain medication appears not to be associated with substance misuse or smoking in later life.

Parenteral opioids for maternal pain relief in labour

BACKGROUND

Parenteral opioids are used for pain relief in labour in many countries throughout the world.

OBJECTIVES

To assess the acceptability, effectiveness and safety of different types, doses and modes of administration of parenteral opioids given to women in labour.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (January 2010) and reference lists of retrieved studies.

SELECTION CRITERIA

We included randomised controlled trials examining the use of intramuscular or intravenous opioids (including patient controlled analgesia) for women in labour. We looked at studies comparing an opioid with placebo or another opioid.

DATA COLLECTION AND ANALYSIS

At least two review authors independently assessed study eligibility, collected data and assessed risk of bias.

MAIN RESULTS

We included 54 studies involving more than 7000 women that compared an opioid with placebo or another opioid administered intramuscularly or intravenously. The 54 studies reported on 27 different comparisons, and for many outcomes only one study contributed data. Overall the evidence was of poor quality regarding the analgesic effect of opioids, satisfaction with analgesia, adverse effects and harm to women and babies. There were few statistically significant results. Many of the studies had small sample sizes, and low statistical power. Overall, findings indicated that parenteral opioids provided some pain relief and moderate satisfaction with analgesia in labour, although up to two-thirds of women who received opioids reported moderate or severe pain and/or poor or moderate pain relief one or two hours after administration. Opioid drugs were associated with maternal nausea, vomiting and drowsiness, although different opioid drugs were associated with different adverse effects. There was no clear evidence of adverse effects of opioids on the newborn. We did not have sufficient evidence to assess which opioid drug provided the best pain relief with the least adverse effects.

AUTHORS' CONCLUSIONS

Parenteral opioids provide some relief from pain in labour but are associated with adverse effects. Maternal satisfaction with opioid analgesia was largely unreported but appeared moderate at best. We did not examine the effectiveness and safety of parenteral opioids compared with other methods of pain relief in labour and this review needs to be examined alongside related Cochrane reviews. More research is needed to determine which analgesic intervention is most effective, and provides greatest satisfaction to women with acceptable adverse events for mothers and their newborns.

Gastric suction at birth associated with long-term risk for functional intestinal disorders in later life

OBJECTIVE

To test the hypothesis that noxious stimulation at birth may increase the long-term risk for developing psychosomatic or functional disorders during later life.

STUDY DESIGN

Matched case-control study using sibling controls. The birth records were retrieved for the offspring of 494 mothers who, after uncomplicated pregnancies, had delivered two or more children with birth weights at least 2500 g, if at least one child was exposed to a perinatal complication or birth asphyxia. Among their offspring (N=1110), the 108 cases hospitalized for functional intestinal symptoms were identified from nationwide hospital discharge records. Of these, 96 cases were compared with 116 unaffected sibling controls.

RESULTS

Functional intestinal symptoms occurred more commonly among the 1110 subjects (9.5%) than in the general population (3.4%, chi(2)=124, P<10(-6)). Gastric suction at birth occurred more frequently among the cases compared with their siblings (22.9% vs 11.2%). There were no differences in the number of cases and controls exposed to perinatal trauma or birth asphyxia. Multivariate logistic regression analyses showed that gastric suction at birth was associated with functional intestinal disorders during later life (odds ratio, 2.99; 95% confidence interval, 1.32-6.79; P=.009), whereas maternal, perinatal, or other confounding variables were not significant.

CONCLUSIONS

Noxious stimulation caused by gastric suction at birth may promote the development of long-term visceral hypersensitivity and cognitive hypervigilance, leading to an increased prevalence of functional intestinal disorders in later life.

Outcomes of infants born to mothers receiving methadone for pain management in pregnancy

OBJECTIVE

To assess the outcomes of infants born to mothers receiving methadone for the management of pain in pregnancy.

DESIGN

A retrospective audit was conducted of neonatal outcomes in 19 cases in which methadone was used in the management of maternal pain (pain group). Twenty four cases in which methadone was used for maintenance of opiate addiction in pregnancy served as a comparison group (maintenance group).

SETTING

Regional level 3 neonatal service.

RESULTS

Infants in the pain group were exposed to significantly smaller methadone doses, for shorter periods, starting later in pregnancy. Only 11% of them required treatment for neonatal abstinence syndrome, whereas 58% of infants in the maintenance group required treatment. Other neonatal morbidity in the pain group was considerable, probably related to prematurity. Infants in the pain group had significantly higher z scores for birth weight and head circumference, but not length, than the infants in the maintenance group.

CONCLUSIONS

Methadone used for the treatment of maternal pain resulted in a low incidence of neonatal abstinence syndrome. Infants were normally grown. However, there was significant morbidity related to slight prematurity, and delivery in this group should be delayed until term if possible.

Perinatal medication as a potential risk factor for adult drug abuse in a North American cohort

The aim of this study was to explore perinatal exposures to medications as risk factors for adult drug abuse. We compared 69 drug abusing subjects and their 33 non-abusing siblings with regard to history of labor pain analgesia during birth and other obstetric variables. Three or more doses of opiates or barbiturates at birth yielded an OR of 4.7 (95% CI = 1.0-44.1) for becoming a drug abuser after multiple perinatal drug exposure.

Is it time to change the paradigm?

Published research has suggested that infants whose mothers received opiates, barbiturates, or nitrous oxide gas during labor are significantly more likely to become addicted to opiates if they experiment with drugs in later life. Why has no one further investigated this hypothesis? What if these researchers are correct? In the future will there be class action lawsuits against the medical and nursing research communities for failure to follow up on this question? Is it time to change the research paradigm?

Obstetric care and proneness of offspring to suicide as adults: case-control study

OBJECTIVE

To investigate any long term effects of traumatic birth and obstetric procedures in relation to suicide by violent means in offspring as adults.

DESIGN

Prospective case-control study.

SETTING

Stockholm, Sweden.

SUBJECTS

242 adults who committed suicide by violent means from 1978 to 1995, and who were born in one of seven hospitals in Stockholm during 1945-80, matched with 403 biological siblings born during the same period and at the same group of hospitals.

MAIN OUTCOME MEASURES

Adverse and beneficial perinatal factors expressed as relative risks (odds ratios) and 95% confidence intervals, derived from logistic regression of cases matched with their siblings.

RESULTS

For multiple birth trauma the estimated relative risks of offspring subsequently committing suicide by violent means were 4.9 (95% confidence interval 1.8 to 13) for men and 1.04 (0.2 to 4.6) for women. In mothers who received multiple opiate treatment during delivery, the estimated relative risk of offspring subsequently committing suicide was equal for both sexes (0.26, 0.09 to 0.69).

CONCLUSION

Minimising pain and discomfort to the infant during birth seems to be of importance in reducing the risk of committing suicide by violent means as an adult.

Traditional analgesic agents: are parenteral narcotics passé and do inhalational agents still have a place in labour?

Systemic labour pain treatment with opioids and inhaled nitrous oxide has for many decades frequently been used in medically developed countries. Self-administered nitrous oxide (50% in oxygen) has never gained the same popularity in the USA as in the UK or Scandinavia but the use of opioids, mainly pethidine, has generally been widespread in spite of well-known negative effects on the postnatal adaptation of the newborn. Since the often very intense labour pain seems to respond very poorly even to highly sedating doses of parenteral opioids, their frequent use during delivery and parturition has to be questioned. Self-administered inhalation of nitrous oxide 50% in oxygen also has a limited efficacy for relieving labour pain but because it is mainly devoid of adverse effects on the baby or on the parturient its future use in obstetrics can be defended more easily, either as a sole agent in women with low labour pain scores or in early labour preceding epidural analgesia.

Labor analgesia and infant brain development

A large percentage of newborns are exposed to pharmacological agents that affect the brain in connection with pain management during labor. The two most commonly used agents are meperidine, administered intravenously or intramuscularly, and bupivacaine, administered by the epidural route. Over the years, infant behavioral assessments have been used in the neonatal nursery to identify labor analgesia regimens with minimal impact on neonatal status. However, considerable controversy has centered on the general issue of possible harm to the neonate from use of analgesia and anesthesia in obstetrics. Due to limitations on experiments in the obstetric situation and a lack of suitable animal models, the broader issues concerning the effects of these agents on the developing brain and possible long-term consequences for infant adaptive functioning have received little attention. A series of studies has recently been completed using a rhesus monkey model for administration of labor analgesia under controlled experimental conditions and long-term behavioral evaluation of infants. Most of the assessments, including those of cognitive function, were not influenced by perinatal analgesia. However, these studies have confirmed the neonatal depressant effects of meperidine and have suggested that the course of behavioral maturation during certain periods of infancy is influenced by both meperidine and bupivacaine administration at birth. These effects could occur as a result of effects on vulnerable brain processes during a sensitive period, interference with programming of brain development by endogenous agents, or alteration in early experiences.

Breast feeding and anaesthesia

Anaesthetists require a good knowledge of the excretion of drugs in breast milk and the potential hazards to suckling infants of drug ingestion via breast milk. A brief account of the physiology of lactation is given. The mechanisms of drug passage into breast milk are discussed followed by a review of the excretion in breast milk of drugs used in anaesthetic practice. Suggestions for the management of anaesthesia in breast feeding mothers are offered.

Obstetric medication versus residential area as perinatal risk factors for subsequent adult drug addiction in offspring

In an attempt to explain pronounced uneven distributions of births of subsequent amphetamine and opiate addicts at seven hospitals in Stockholm, two possible mechanisms for adult drug addiction were weighed against each other: (1) risk factors associated with the obstetric care at the hospitals of birth of the addicts and (2) risk factors associated with the phenomenon of 'contagious' transmission of drug addiction in certain residential areas during adolescence. The subjects comprised 200 amphetamine addicts and 200 opiate addicts born between 1945 and 1966. By loglinear analysis the relative risk for future addiction was determined for eight residential areas as well as for the seven hospitals and four periods of birth. For the opiate addicts only one weak association was found for the residential area, which could not explain fully a clustering of births at any particular hospital. For the amphetamine addicts, hospital of birth was found to be an important risk factor even after controlling for residential area. Hence, the variable residential area has not been able to explain the uneven distribution of births of drug abusers among the studied hospitals.

Socio-economic versus obstetric risk factors for drug addiction in offspring

Two possible risk factors for drug addiction were weighed against each other: (1) perinatal factors associated with obstetric medication at time of birth; and (2) factors associated with familial socio-economic conditions at time of birth. The subjects comprised 200 amphetamine addicts and 200 opiate addicts born in Stockholm 1945-1966. In a matched case control study, addicts were compared to their siblings with regard to possible obstetric risk factors by means of conditional logistic regression controlling for socio-economic level and civil status. Administration of opiates, barbiturates and nitrous oxide to mothers during labour was associated with drug addiction in offspring, hence confirming results from earlier studies. In a cohort study the risk associated with birth at a given hospital and familial socio-economic level was analysed by means of log-linear analysis using 7100 controls from the general population. For amphetamine addicts, a low socio-economic level at time of birth might be of importance for the infant subsequently becoming an addict. This could not be demonstrated for the opiate addicts. An uneven distribution of births among the hospitals, most pronounced for the amphetamine addicts, is in agreement with the hypothesis that obstetric practices may be risk factors for adult drug addiction.

Endogenous opiates: 1990

This paper, an examination of works published during 1990, is thirteenth in a series of our annual reviews of the research involving the behavioral, nonanalgesic, effects of the endogenous opiate peptides. The specific topics this year include stress; tolerance and dependence, eating; drinking; gastrointestinal, renal, and hepatic functions; mental illness; learning, memory, and reward; cardiovascular responses; respiration and thermoregulation; seizures and other neurological disorders; electrical-related activity; locomotor activity; sex, pregnancy, development, and aging; immunological responses; and other behavior.