Effects of binding on human transplacental transfer of cocaine

Cocaine and its metabolites in the placenta: a systematic review of the literature

It is clear that cocaine and cocaine metabolites are present in the placenta and may harm the fetus. The results of the experimental manipulation of cocaine exposure are not reported in the literature in a consistent manner. We conducted a systematic review of selected articles that demonstrated the analytical detection of cocaine and its metabolites in the placenta and that were published from January 1, 1956-June 30, 2011 using Medline, Toxline and Scopus databases. The collected data confirm that the placenta does not act as a barrier to fetal exposure, that cocaine quickly crosses the placenta and that one of the essential roles of the placenta is to metabolize cocaine during pregnancy. Our systematic review summarized the results showing that cocaine, benzoylecgonine and norcocaine are stored in the myometrium and the placental membrane and maintain continuous drug delivery to the amniotic fluid (and to the fetus) probably via diffusion.

Fetal effects of cocaine: an updated meta-analysis

BACKGROUND

A very large number of women in the reproductive age group consume cocaine, leading to grave concerns regarding the long term health of millions of children after in utero exposure. The results of controlled studies have been contradictory, leading to confusion, and, possible, misinformation and misperception of teratogenic risk.

OBJECTIVE

To systematically review available data on pregnancy outcome when the mother consumed cocaine.

METHODS

A meta-analysis of all epidemiologic studies based on a priori criteria was conducted. Comparisons of adverse events in subgroups of exposed vs. unexposed children were performed. Analyses were based on several exposure groups: mainly cocaine, cocaine plus polydrug, polydrug but no cocaine, and drug free.

RESULTS

Thirty three studies met our inclusion criteria. For all end points of interest (rates of major malformations, low birth weight, prematurity, placental abruption, premature rupture of membrane [PROM], and mean birth weight, length and head circumference), cocaine-exposed infants had higher risks than children of women not exposed to any drug. However, most of these adverse effects were nullified when cocaine exposed children were compared to children exposed to polydrug but no cocaine. Only the risk of placental abruption and premature rupture of membranes were statistically associated with cocaine use itself.

CONCLUSIONS

Many of the perinatal adverse effects commonly attributed to cocaine may be caused by the multiple confounders that can occur in a cocaine using mother. Only the risk for placental abruption and PROM could be statistically related to cocaine. For other adverse effects, additional studies will be needed to ensure adequate statistical power.