"Marijuana has not been implicated as a human teratogen. No homogeneous pattern of malformation has been observed that could be considered characteristic of intrauterine marijuana exposure.6 Among 202 infants exposed to marijuana prenatally, the rate of serious malformations was no higher than the rate among infants whose mothers did not use marijuana."
Kozer, E., & Koren, G. (2001). Effects of prenatal exposure to marijuana. Canadian family physician Medecin de famille canadien, 47, 263–264.