Lead author James Roney, a professor at the University of California, Santa Barbara, and colleagues demonstrated hormonal predictors for sexual desire.
The findings, published in the journal Hormones and Behavior, found when hormone levels and sexual desire were factored against the menstrual cycles of undergraduate students, the researchers observed a measurable increase in progesterone levels at the same time the subjects noted decreases in sexual motivation.
When a woman's cycle is high in estrogen she might feel a greater desire for sex, but when the cycle has higher levels of progesterone -- the second half of the menstrual cycle -- this hormone has a desire-deadening affect.
Roney noted the findings don't present a full model, and he'd like to replicate his results with women of different age groups.
"Undergraduate [women] might be unique for a lot of reasons," he said. "Their hormone levels tend to be a bit different from those of women even just a little bit older. And married women in their 30s are likely to be more consistently sexually active, and that might change the patterns in some ways."