It is recommended to wait at least 3 months after the last consumption of marijuana before trying to conceive in order to reduce the risk of miscarriage. Studies have shown that marijuana use during conception can be linked to miscarriages, developmental delays in children, and low birth weight. It is important to minimize exposure to secondhand marijuana smoke, especially if your partner is a marijuana user. It is also advisable to limit your partner's marijuana consumption as much as possible to increase the chances of a successful conception. As for the exact timeframe to wait between stopping marijuana consumption and conception to reduce the risk of miscarriage, there is no clear and definite answer based on current research.