DRUG USE AND PREGNANCY

by Dr Mary Hepburn.

Use of illicit drugs is increasing steadily, but with a disproportionate rise among women. When used during pregnancy drugs can have adverse effects on the baby's health and on the mother's parenting abilities. Drug using women are therefore frequently viewed as irresponsible and as inadequate parents who should not retain custody of their child(ren). However other factors are frequently present which also affect pregnancy outcome.

Problem drug use often occurs in association with socio-economic deprivation while women who use drugs often smoke. Consequently it is often impossible to study the effects due to other causes. There is consequently a dearth of reliable data and recommended managements of drug use in pregnacy often lack a sound scientific basis.

Precise action and information about the action of individual drugs varies. While opiates are perhaps the most extensively studied the broad similarities between the effects of drug use in pregnancy fall into two main categories. Firstly drug using women are reported to be at greater risk of spontaneous abortion and to have higher rates of morality and morbidity due to increased risk of premature birth and/or low birth weight. The risk of cot death is also reported to be higher. When drug use is chaotic with fluctuating levels of use the likely severity of such effects is increased and sudden complete drug withdrawal has been reported to cause death of the fetus. Therefore while drug use during pregnancy is regarded as harmful to the fetus antenatal detoxification is considered even more dangerous and permissible only with very slow reduction in mid trimester. The view that women should receive maintenance throughout pregnancy is still widely held.

The second way in which drug use can affect the baby is by causing withdrawal symptoms which in general are more likely or likely to be severe the greater amount of drug used. Babies of drug using women are often routinely admitted to the special care nursery and frequently given treatment for, or in anticipation of, withdrawal symptoms. Such symptoms, a source of great distress to the mother, can therefore cause further distress through separation of the mother and baby.

Social management of drug using women after delivery has often reflected the view that drug use is incompatible with adequate child care but antenatal maintenance and postnatal abstinence are largely incompatible. Trying to enforce the latter may prove a confrontational distraction.

Pre-term delivery and/or low birth weight have implications for health in later life but such effects are non-specific and can occur with use of legal drugs such as tobacco (where the effect on birth weight is much greater) or due to socio-economic deprivation per se. However, while erratic patterns of drug use undoubtedly exacerbate such effects we have observed no adverse fetal effects from antenatal detoxification at any speed, any gestation or any number of times. Neonatal withdrawal symptoms while sometimes exacerbated by other factors such as prematurity are more specific to drug use. However in our experience they are of limited duration with no long-term harmful effects on the babies and do not invariably require treatment or even admission to the special care nursery.

While in general the greater the level of drug use the greater the likelihood or likely severity of the mother's drug use from the condition of her baby. Nevertheless most women are keen to reduce their drug use during pregnancy particularly to reduce the likelihood of severe withdrawal symptoms. However child care is compromised not by drug use per se but by a chaotic pattern of use, so postnatal abstinence is not essential.

Maintenance therapy and detoxification are therefore both valid treatment options and are not mutually exclusive.Poor pregnancy outcome is multifactorial while the presence or severity of neonatal withdrawal symptoms may not reflect the level of the mother's drug use. The baby's condition should therefore not be used as an indicator of whether or not the mother should get custody. Social services should play a supportive and not a punitive role in the management of pregnant drug using women who in turn should be involved in decisions about their own management. Such management should be based on scientific data and not on conjecture or moral prejudice.

Dr Mary Hepburn is senior lecturer in Women's Reproductive Health, and consultant obstetrician and gynaecologist at Glasgow Royal Maternity Hospital.