In my opinion and based upon studies that I have read marijuana use can harm female fertility and lead to reduced annual menstrual cycles in women and also reduced egg production with excessive or prolonged use as can the use of other medications and intoxicants like alcohol. Women who want to conceive should practice moderation in everything except copulation.
Studies show that smoking decreases fertility. This information alone should allow you to conclude that smoking marijuana will decrease female fertility. It is also harmful for the child once you have become pregnant. Smoking marijuana actually does nothing productive medically despite what rampant pot smokers would lead you to believe. It simply gets you high.