No safe level of alcohol consumption in pregnancy has been established, although it is generally believed that consumption of more than 12 units of alcohol daily, especially in a binge drinking pattern, holds significant risks for the foetus. In the USA, it has been estimated that foetal effects of alcohol are recognisable in 1 in 100 births, while the more severe foetal alcohol syndrome occurs in between 1 in 300 and 1 in 1000 births. The latter is characterised by high rates of mental retardation, neurological deficits and behavioural problems in the child.
The biological treatment of choice for the physically dependent pregnant mother is detoxification. This should generally take place in an in-patient setting with collaboration from an obstetrician. Patients who are physically dependent on alcohol should always be advised to avoid sudden cessation of alcohol consumption, and in the pregnant woman, there is the additional threat to the life of the foetus. Differentiation of symptoms of alcohol withdrawal from symptoms of pregnancy may be difficult, but tremor and fever should usually be specific for alcohol withdrawal.
For anything other than a mild physical withdrawal from alcohol, the use of medication to control withdrawal should be considered; uncontrolled withdrawal seizures, hypertension, tachycardia and agitation pose serious risks to both the mother and foetus and will nearly always require pharmacologic intervention.
Usually, the first choice agent will be chlordiazepoxide, or possibly diazepam. However, if high doses are required (>30mg diazepam equivalent in 24 hours), there is a risk of foetal or neonatal toxicity. External cardiac monitoring of the foetal heart will be required in such cases, under specialist obstetric care. If detoxification is taking place near the end of pregnancy, toxicity may present as \’floppy baby syndrome\’ which may be reversed with flumazenil under specialist obstetric/ paediatric care. Conversely, if benzodiazepines are needed for more than a few days near the end of pregnancy, the newborn may show signs of benzodiazepine withdrawal, characterised by increased tone, hyperreflexia and tremor. This will usually resolve spontaneously without specific intervention.
There is no clear evidence to demonstrate any teratogenic effect of benzodiazepine use in pregnancy, and the bulk of the evidence suggests that the benefits of the short-term use of benzodiazepines for alcohol detoxification outweigh the risks posed by an uncontrolled withdrawal.
As for alcohol, the treatment of choice is controlled withdrawal in an in-patient setting.As well as the usual, potentially life-threatening effects of an uncontrolled withdrawal to the mother, there is the additional risk of foetal respiratory arrest. Conversion to a long-acting benzodiazepine such as chlordiazepoxide, followed by dose-tapering, with specialist obstetric collaboration will usually be the treatment of first choice.
The treatment of choice is withdrawal due to the risks associated with cocaine misuse during pregnancy. There is no clear recommendation regarding the use of medication to assist withdrawal. In cases of extreme agitation, it may be prudent to prescribe low dose chlordiazepoxide, but such a decision must be made on a case-by-case basis.
In contrast to the other drug classes, the treatment of choice for opiate dependency in pregnancy is methadone maintenance. Such an approach is aimed at the primary goal of stabilising behaviour and enhancing engagement with antenatal care. In addition, opiate withdrawal may theoretically be associated with an increased risk of spontaneous abortion and premature labour. The overall evidence indicates that low dose maintenance is the best option for ensuring continuity of management of pregnancy and aftercare. However, higher doses may be required if non-prescribed opiate use persists or recurs. In the third trimester, many women will need an increased methadone dose because of various physiological changes and weight gain. Dividing the daily dose can sometimes overcome the need for an increase in the dose in the later stages of pregnancy. There is no clear relation between the intensity of neonatal withdrawal and maternal methadone dose at delivery (Finnegan LP, 1990), although studies have suggested that neonatal withdrawal reactions diminish with methadone doses of under 15mg daily.
If a woman is highly motivated to undergo detoxification, this may be supported, but should take place in an in-patient setting with obstetric supervision. The regime of choice in such cases has been a slow reduction in methadone dosage at the rate of 2 to 2.5mg every 7 to 10 days; thus it will often prove impractical to arrange detoxification due to the long period of in-patient admission required to perform the intervention to the required standard of safety. However, a recent study of clonidine and/or methadone detoxification in 34 women in the second trimester found no evidence of foetal distress during detoxification, no foetal death and no delivery before 36 weeks. The authors (Dashe J et al, 1998) concluded that in selected patients, opioid detoxification can be accomplished safely during pregnancy.
Several studies have also appeared to demonstrate that buprenorphine (Subutex) is a safe alternative for maintenance prescribing in pregnancy, and may decrease the intensity of the neonatal opioid withdrawal syndrome (Johnson R et al, 2001). However, due to the small numbers involved in these studies, and the need for replication of results, Subutex should not be commenced in pregnancy. Where a woman becomes pregnant whilst already prescribed Subutex, a judgement will have to be made regarding its continuation, taking into account the benefits and risks to the mother and foetus.
Opiate intoxication in pregnancy should only be treated with naloxone as a last resort due to the associated risk of spontaneous abortion or premature labour/stillbirth.
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The above information is copyright of Dr Bruce Trathen MBBS MRCPsych (2006). ISBN 0-9545164-0-0. The author grants permission for these guidelines to be downloaded, copied and distributed freely, but does not grant permission for their sale.