Q: Does a vegetarian diet lead to infertility? 

A: In one study called “Dieting Influences The Menstrual Cycle: Vegetarian Versus Nonvegetarian Diet,” 18 healthy, normal-weight women aged 19 to 27 years who had regular ovulation and menstrual cycles volunteered for a study.

Nine women followed a vegetarian diet and nine a nonvegetarian diet. Both groups lost an average of 1 kg body weight/week. Seven of nine women in the vegetarian group became anovulatory while seven of nine women in the nonvegetarian diet group maintained ovulatory cycles with no changes in cycle length or in the length of the follicular phase.

During the vegetarian diet, the average luteinizing hormone (LH) values were significantly decreased during the midcycle and the luteal phase. Estradiol (E2) and progesterone (P) values were significantly lower during the luteal phase. In contrast, the nonvegetarian group did not show significant reduction of LH, E2, and P values during any part of the menstrual cycle.

Pirke KM, et al: Fertil Steril 1986 Dec;46(6):1083-8