Cigarettes seem to shorten the follicular phase but heavier smoking also may shorten the luteal phase. Both heavy smoking and even smoking just 10 cigarettes or more a day may cause menstrual cycles to be shorter in length, as well as more variable in their lengths than nonsmokers. Sometimes it shortens cycles while at other times it can cause a delay of menses. The alcohol is thought to affect the liver's ability to properly metabolize estrogen and progesterone. There are many things that can block ovulation in women.
Stress is the most common cause.
If there are no menses at all, this is called hypothalamic amenorrhea. The mechanism for this is not totally known but probably has to do with alteration of brain proteins and hormones so that the normal ovulatory releasing factors do not work. When the brain releasing factors do not stimulate follicle development, there are few estrogens produced and a woman is then at risk for osteoporosis at a young age. This is why physicians prescribe estrogens in this condition, i.e., to prevent bone loss. Long distance runners and other strenuous sports have been well known to cause anovulation of the low estrogen type.