John Witton, MD, Health Services Research Co-ordinator at the National Addiction Centre at King's College London, stated in a Mar. 25, 2003 BBC News article:
"Previous studies have shown that children who have been exposed to cannabis in the womb have poor attention, memory and cognitive functioning. However, these effects are small compared to those from tobacco.
Cannabis exposure may be to blame, but a child's development may also be affected by the reasons underlying some mothers' choice to use cannabis during pregnancy."
Charles Ksir, PhD, Professor of Psychology at the University of Wyoming, and Oakley Ray, PhD, Emeritus Professor of Psychology and Pharmacology at Vanderbilt University, wrote in their 2004 textbook Drugs, Society and Human Behavior:
"A number of studies have reported either lower birth weight or shorter length at birth for infants whose mothers smoked marijuana during pregnancy.
Although these effects are small and inconsistent from one study to the next, it is, of course, wise to avoid the use of all drugs during pregnancy."
The National Institute on Drug Abuse (NIDA) wrote in its webpage "Marijuana: Fact Parents Need to Know" on drugabuse.gov (accessed Oct. 18, 2011):
"Marijuana use during pregnancy may adversely affect the fetus. Animal research suggests that the endocannabinoid system plays a role in the control of brain maturation, particularly the development of emotional responses. In humans, the data are less conclusive—in part, because it is difficult to disentangle the drug-specific factors from the environmental ones. For example, pregnant women who use marijuana may also smoke cigarettes or drink alcohol, both of which can affect fetal development. Nevertheless, research suggests that babies born to women who used marijuana during their pregnancies may have subtle neurological alterations and, as children, can show diminished problemsolving skills, memory, and attentive processes. Although, the extent to which these effects reflect marijuana use or other drugs is unclear."
Hillary Klonoff-Cohen, PhD, Professor of Family and Preventative Medicine at the University of California and San Diego, et al., stated the following in their July 2001 article titled "Maternal and Paternal Recreational Drug Use and Sudden Infant Death Syndrome," published in the Archives of Pediatrics and Adolescent Medicine:
"There was no association between maternal recreational drug use and SIDS [Sudden infant death syndrome]. Paternal marijuana use during the periods of conception and pregnancy and postnatally were significantly associated with SIDS... Before any definitive role for the father can be confirmed, these findings should be investigated and replicated in future studies...
We found an association between SIDS and paternal marijuana use during all periods, whereas this was not the case with maternal use. This may be due to the larger number of men who smoked marijuana (compared with very few women) or to the greater amount, frequency, and duration of their use. Finally, men may not be aware that their lifestyle habits affect pregnancy outcomes."
British Broadcasting Corporation (BBC) reported in a Mar. 25, 2003 article about a study published by Proceedings of the National Academy of Science titled "Prenatal Exposure to a Cannabinoid Agonist Produces Memory Deficits Linked to Dysfunction in Hippocampal Long-term Potentiation and Glutamate Release," by Giampaolo Mereu et al.:
"Exposure to a cannabis in the womb could cause children to experience learning difficulties and hyperactivity, researchers suggest.
Research was carried out on rats using an artificial cannabinoid, a cannabis extract. Cannabis is the most widely used drug by women at reproductive age.
Previous research has shown that babies born to mothers who took cannabis while they were pregnant go on to experience problems with physical activity."