Treating pregnant drug users

By Lunar Loops · Jun 24, 2006 ·
  1. Lunar Loops
    This from the Irish Medical News website ( :

    Treating pregnant dug users

    The use of psychoactive drugs is common in Ireland, however, accurate estimates of prevalence rates during pregnancy are hindered by issues such as guilt and denial by the drug user and prejudice and stigma by society, all of which can act as barriers to a comprehensive assessment of a pregnant woman and her effective engagement with addiction and obstetric services. This applies to a pregnant woman who uses both legal and illegal drugs. We will highlight some of the problems associated with drug use in pregnancy, focusing on opiates, stimulants, and benzodiazepines, and offer some guidelines to best practice.
    At present in Ireland, according to the most recent National Advisory Committee on Drugs (NACD) population survey, the estimated lifetime prevalence rates for any illegal drug is 18.5 per cent (see Table 1 for details).
    Much higher rates are found for alcohol and tobacco use, both of which have well documented harmful effects on the developing foetus, neonate, and child. The European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) 2002 estimated that about 5.7/1,000 of the population aged between 15 and 64 engage in “problem drug use”, which they define as injecting drug use or long duration use of opiates, cocaine, and/or amphetamines.
    Ireland has one of the youngest treated populations of opiate abusers in Europe. In the Dublin area, prevalence rates in the 15-to-24 age groups are estimated to be as high as 32/1,000 for males and 17/1,000 for females. This study also showed that while prevalence rates for males in general decreased compared to earlier studies, the number of female opiate users increased significantly across all age bands. More of a concern is the evidence to suggest that the number of young female injectors may be increasing.
    While examing this study, keep in mind that population surveys tend to miss marginalised groups such as the homeless and travellers, it is likely that these figures underestimate the problem of drug abuse in pregnancy.
    The central treatment list is a register of all people prescribed methadone in the Irish republic. As of January 2006, there were 7,933 on this list; 2,450 of these were women (30.9 per cent), the majority of whom are of childbearing age. In 2005, 193 infants were born in the three Dublin maternity hospitals to women on methadone treatment.
    Pregnancy is a potential time of anxiety for any woman, as relationship, financial, and housing issues become more prominent; some can be snowed under by an unexpected pregnancy. Drug-taking women, especially those using heroin, may have menstrual irregularities, and early pregnancy signs and symptoms may be misinterpreted as withdrawals. It is not unusual for pregnancy to cause a female drug user to seek treatment for the first time.
    Psychological dependence on drugs usually leads to the prioritising of drugs over other needs and limited finances are often by necessity supplemented by crime and/or sex-work, both of which pose further risk to the pregnant drug user. If using intravenously and in an unsafe manner, the woman puts herself at risk of blood-borne viral diseases. Maternal infection, poor self-care, malnutrition, and smoking all contribute to the observed low birth weights, pre-term delivery, and the poor nutritional status associated with babies born to drug users.
    Though some studies have identified evidence of irreversible chromosome damage in foetuses exposed to drugs, so far there is only evidence of teratogenicity specifically related to benzodiazepines and cocaine, and not opioids. There is, however, strong evidence that exposure to heroin directly causes foetal growth retardation and low birth weight; drugs in general can contribute to preterm delivery, stillbirth, and sudden infant death syndrome and neonatal abstinence syndromes. Harm can be due to the direct effects of drugs, maternal infection, malnutrition, poor self-care, and smoking, all of which are made worse by inadequate antenatal care; these women often present late, if at all, to the obstetric services, and for various reasons, may not engage adequately engage with their antenatal care.

    Heroin use in pregnancy may lead to low birth weights, premature delivery, stillbirth, and neonatal death. Ideally, when an opiate-dependant woman becomes pregnant, she should abstain from further opiate use. However, many cannot do this fully due to the nature of addiction. So, they should be prioritised into substitution treatment, where the first step is a comprehensive assessment (see Box 1).
    Even in treatment continued heroin use can occur, creating fluctuating blood opiate levels as the patient cycles between intoxication and withdrawal; these erratic blood opiate levels similarly effects the developing foetus leading to foetal distress. If the patient is using intravenously, she and her baby are at risk to the effects of blood-borne diseases, septicaemia, blood clots, and abscesses.
    Many women request detoxification when they discover they are pregnant, but this is often not practical due the risks this poses to the foetus, and the likelihood of relapse. The ability of methadone to promote stability is well documented at this stage. In Ireland, in light of this evidence, methadone is the main substitute medication used for the treatment of opiate dependence. The outcomes for the mother and her infant are better if she is stable on methadone. If the pregnant women opts for detoxification, this is usually done relatively safely in the second trimester, as miscarriage is a risk in the first trimester, and premature/stillbirth delivery in the third trimester.
    After delivery, between 48-to-94 per cent of neonates exposed to opioids during pregnancy develop signs of withdrawal. This neonatal abstinence syndrome (NAS) usually begins in the first 24-to-72 hours, but with methadone, can begin later and last longer.
    The signs of this include: high-pitched cry; rapid breathing; hungry but ineffective sucking; excessive wakefulness; tremor; vomiting and diarrhoea; hypertonicity; sweating; and rarely, seizures. When these occur, how long they last, and how severe they become depend on many factors including: the type of drug(s) used; the amounts used; when taken in relation to delivery; and the condition of the infant after birth. While research carried out in our own service indicated that higher maternal methadone dose is associated with an increased risk of NAS, debate about this exists in the literature.
    The balance of evidence suggests that the benefits of substitution outweigh the risk of NAS. As pregnancy advances, many pregnant women may require higher doses of methadone to maintain stability because of weight gain and physiological changes associated with pregnancy. In some select cases were the patient is well motivated, supported, and stable, the option of dividing the daily dose is a possibility, but for practical reasons related to service delivery, this is often not possible. The most important treatment issue is the promotion of stability of drug use and lifestyle, and many methadone-maintained pregnant women can refrain from heroin use when provided an appropriate methadone dose, psychological, social, and medical support. However, if poly-substance misuse persists, methadone dose may have to be reduced for safety reasons. In very recent times in Ireland, buprenorphine, a partial opiate receptor agonist is being used as a substitution/detoxification medication, but it is not yet licensed in Ireland for use in pregnant women. There is accumulating evidence that infants borne to women on buprenorphine may be at a lower risk of NAS and this option will exist in the future.

    Stimulant use
    Amphetamine use has been a problem in Ireland for many years, but cocaine use has become much more common in recent years (see Table 1). Cocaine use in pregnancy is associated with premature birth, foetal growth retardation, low birth weight, and smaller head circumference. Stillbirth rates and congenital defects may also be increased. Though teratogenic evidence is preliminary and inconsistent, mothers should still be advised that cocaine may increase the risk of congenital malformations. The neonate does experience difficulties when cocaine is used near term such as irritability, hypertonia, and sleep/appetite disturbance. These effects only last a few days, and generally do not require treatment; these are thought to be due to direct toxic effects of cocaine rather than reflecting withdrawal. The use of cocaine and heroin in pregnancy has been reported to increase the risk of NAS. Unlike for people using opioids, there is no substitution medication for stimulants. The only option for the pregnant user is abstinence; cognitive-behavioural therapy and motivational enhancement therapy have been shown to be able to promote and maintain this.
    The use of sedatives in pregnancy is an under-studied area. However, there is evidence to suggest that their use in pregnancy, especially in higher doses, is associated with low birth weight and cleft lip/palate. Use of these near term can lead to the “floppy baby syndrome”’ and benzodiazepine withdrawal in the neonate. Because of the longer half-life of these drugs, onset of withdrawal can be delayed and duration prolonged. This can often complicate the problem of opioid withdrawal and, in addition, sedatives are more likely to cause respiratory depression and seizures. The combined use of opiates and sedatives is particularly dangerous for both the expectant mother and her infant. There are places in the two Dublin drug detoxification units specifically for people in need of stabilisation, and these pregnant women are encouraged to avail of these. In some circumstances, therapeutic doses of benzodiazepines may be prescribed to discourage illicit use. Treating-doctors and society have a duty of care to the pregnant substance misusing woman and her infant. This is best done with a multidisciplinary team approach that liaises effectively with the obstetric services. Throughout this process it must be remembered that most pregnant women remain stable in their drug use and, as mothers, can care adequately for their children, especially if offered non- judgemental support.

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