Effects of prenatal exposure to cannabinoids.

Prenatal exposure to cannabinoids does not produce gross malformations in humans and only does so with any consistency in mice following exposure to relatively high doses and following the intraperitoneal route of administration. Resorption rates are reliably increased in mice but not rats following in utero cannabinoid exposure. There is also a reliable decrease in maternal food and water consumption and weight gain during pregnancy associated with maternal cannabinoid administration. This effect may account for many of the effects associated with prenatal exposure to cannabinoids, e.g., increased resorption rate. Prenatal exposure to cannabinoids produces a reliable decrease in birth weight in animals, but this is the only postnatal effect on offspring that has been reliably documented. Studies examining long-term postnatal effects are generally inconsistent. This inconsistency may be due to methodological flaws in experimental design, such as absence of controls for drug-related undernutrition and residual effects of maternal cannabinoid exposure during postnatal nursing. When such controls have been implemented, postnatal effects of prenatal cannabinoid exposure have not been reliably observed.