Exposure to methamphetamine in the womb causes adverse developmental effects

International studies suggest that children exposed to methamphetamine in the womb are likely to suffer adverse developmental effects – either because of the drug, or the environment in which they are subsequently raised.

But University of Auckland developmental health psychologist Trecia Wouldes says further research is needed to pinpoint the impact on infants born to mothers using the drug during pregnancy.

Dr Wouldes – from the Faculty of Medical and Health Sciences – is the author of an international literature review published in this month’s New Zealand Medical Journal. The review was done in collaboration with Drs Linda LaGasse and Barry Lester (Brown University, USA) and Dr Janie Sheridan (School of Pharmacy, The University of Auckland).

Methamphetamine use in New Zealand has largely been associated with young males, but Dr Wouldes says a growing number of women of childbearing age are also using the drug.

“This widespread use has been reflected in the dramatic increase in referrals of women who have used this drug during their current pregnancy to the Alcohol Drug and Pregnancy Team (ADAPT) at National Women’s Hospital. In 2001, 10% (six out of 60) of the total ADAPT referrals were due to methamphetamine use and associated problems. This escalated to 59% (34 out of 58) in 2003,” says Dr Wouldes.

Further anecdotal reports from other antenatal departments of hospitals in the Auckland region and community midwives suggest that a much larger number of women are using or have used methamphetamine during their current pregnancy that have not come to the attention of ADAPT, she says.

Dr Wouldes says there is a paucity of good quality, long-term studies on the effects of the drug on children – and warns against making harsh judgements and punitive policy decisions on the basis of inadequate information.

What little is known about the effects of methamphetamine use during pregnancy on the developing fetus and child comes from three areas: animal studies, a limited number of human studies, and studies of prenatal exposure to other stimulants such as “crack” cocaine.

Animal studies have found a range of possible effects, including increased maternal and offspring death rates, eye problems, cleft palate, rib malformations, decreased rate of physical growth and delayed motor development.

The limited human studies suggest children born to methamphetamine users may be at risk developmentally because of the direct effects of prenatal drug exposure and the caregiving environment associated with that drug use.

Cocaine and methamphetamines have similar pharmacological properties – although methamphetamine has a longer half-life than cocaine. Studies on infants whose mothers took the drug while pregnant have shown these babies often had shorter sleep bouts, and fussed or cried more often than the norm. There was also an effect on their responses to arousal, their attention spans, and motor development.

Dr Wouldes says all illicit drugs taken during pregnancy cross the placenta and reach the fetus – but cautions that the effects of methamphetamine use on a child must also be evaluated in the context of the environment in which that child is subsequently raised.

“There is evidence that maternal drug use is associated with general psychosocial risk factors that may be more pronounced in drug using populations and include poverty, chaotic and dangerous lifestyles, symptoms of psychopathology (e.g. personality disorders, depressive symptoms), a history of childhood sexual abuse and involvement in difficult or abusive relationships with male partners.

“There may be a double jeopardy in which these children are at risk due to the combination of prenatal exposure effects and postnatal environmental effects.”

In her conclusions, Dr Wouldes recommends that: “Firstly, in order to avoid a ‘rush to judgement’ we need well-designed studies to determine if there are effects of methamphetamine use on child outcome.

“Second, if there are effects, we need to develop effective intervention programmes for the infants and their families to reduce methamphetamine related deficits. The cost savings alone from preventing the need for special education services in schools would more than pay for early intervention programmes.”

Dr Wouldes is now developing and seeking the necessary consents to participate in a long-term, international study on the effects of methamphetamine use by pregnant women on children.