USE OF AMFETAMINES IN PREGNANCY

The term ‘‘amfetamines’’ denotes a class of compounds which have structural similarity to ephedrine and includes general amfetamine, dexamfetamines, methamfetamines (or metamfetamines) and the multiple amfetamine analogues.  They are potent sympathomimetic stimulants which exert both central and peripheral effects.  The main central effects of amfetamines include locomotor stimulation, anorexia, euphoria and excitement.  Peripheral effects such as increased blood pressure, excessive sweating and tremor also occur.  Amfetamines may be orally ingested, nasally inhaled, intravenously injected or smoked.

As with all drugs of abuse, it is often difficult to establish exactly which drug has been used.  Exposure to contaminants from illicit production is also a concern.  In addition, recreational drug users are generally considered more likely to display an increased incidence of underlying psychosocial and/or behavioural risk factors for adverse pregnancy outcome including use of other drugs (both legal and illegal), alcohol and tobacco.  Due to data confounding from these factors it is difficult to provide firm conclusions about the risk maternal amfetamine use during pregnancy poses to a developing fetus.

Prospective epidemiological studies into the fetal effects of maternal amfetamine abuse have not conclusively identified an increased risk of congenital malformation.  Increased risks of preterm delivery, low birth weight and small for gestational age deliveries have been suggested.  Where maternal abuse of amfetamine has been sustained throughout pregnancy, or where late gestational exposure has occurred, withdrawal effects in the neonate may occur.  Given the neurotoxic effects of amfetamines, there is concern that in utero exposure may present a risk factor for neurodevelopmental delay in the exposed infant.  However, the available data are limited and confounded and it is therefore not currently possible to describe the existence of an association.

Where amfetamine use has been sporadic, a significant increase in the risk of adverse pregnancy outcomes would not be expected.  However, other risk factors may be present in individual cases which may independently increase the risk of adverse pregnancy outcome.  Clinicians are reminded of the importance of consideration of such factors when performing case-specific risk assessments.  Where prolonged abuse of amfetamine has occurred, additional monitoring may be required.  Discussion with UKTIS is recommended in all cases.