Table 5.

Associations between periconceptional exposures to illicit drugs

		Maternal illicit drug use
Ref.	First author, year	Exposure	OR [95% CI]	Adjustment/matching factors
[41]	van Gelder, 2009*	Cannabis use Cocaine use	0.7 [0.4, 1.2] 0.4 [0.1, 2.7]	Adjusted for: maternal age at delivery, race or ethnicity, level of education, cigarette smoking, binge drinking, pregnancy BMI and periconceptional folic acid use
		Stimulant use	1.1 [0.3, 3.8]	Adjusted for: maternal age at delivery, level of education, binge drinking, pregnancy BMI and periconceptional folic acid use
[1]	Forrester, 2007§†	Methamphetamine use Cocaine use Marijuana use	3.19 [0.87, 11.73] 6.01 [1.05, 34.27] 10.57 [2.87, 38.96]	-

* Exposures at any time between one month before pregnancy and the end of the third month of pregnancy (periconceptional period).

§ Exposures during pregnancy and 1 year after delivery.

† Study reported on the ratio of the rate of illicit drug use among birth defect cases to the rate of illicit drug use among all deliveries. *We calculated the corresponding OR by data given in the article.