Because no studies have been performed on this as of yet, the little we do know is that when you orgasm, the body sends signals to your brain which signals the body to release certain chemicals which may have lasting benefits on your menstrual cycle. We found that women who are exposed regularly to male pheromones via intimate contact have higher estrogen levels and shift to more predictable cycles. This is due to the delicate symphony of hormones in your body. One study found that half of exercising women experience subtle menstrual irregularity. As your progesterone levels fall, your lining also starts to slowly shed. Don't panic if your cycle is a couple days off, but see your doc if your period is consistently over a week early or late. Your hormones are fluctuating all the time throughout your menstrual cycle. If you can't seem to drop pounds, talk to your gynecologist about going on the pill. Still, if you've always weighed less than average, this might not be a problem. Puritz suggests limiting your exposure any way you can: For some women, their period comes on time like clockwork while for others their periods may come a few days earlier or later than expected. That explains why stressed out women were less likely to conceive than their more zen counterparts in a Human Reproduction study. If an egg is not fertilized during midcycle, then in the latter stages of your cycle your uterine lining will thin out because of the rise of prostaglandins levels. According to experts, your hormone levels throughout your cycle can also be greatly influenced by your interactions with love interests. Advertisement 7 of 11 Getty Images Feeling stressed out "Evolutionarily speaking, times of high stress aren't conducive to bringing a baby into the world, and a regular cycle is designed to do just that," says Dr. At the same time, your uterus contracts intensely, though these are way more fun uterine contractions, which can increase menstrual blood flow.