Every month, many women expect a monthly visit from Aunt Flo for about two to seven days. A menstrual period is an occurrence that women experience most of their adult lives; becoming predictable from the day it starts and ends, to how light or heavy the flow is. Yet, like most biological processes, menstruation can deviate from the norm, and be influenced by a variety of everyday factors.

Inevitably, there are a lot of misconceptions about what exactly affects periods and menstruation. Allison Macbeth, Founder & Director of Blue Poppy Health and a Fertility Awareness & Sexual Health Educator, believes the biggest misconception that exists is "we don't have any control over our periods or cycles.”

"The fact is, we can have a huge influence on our hormones through nutrition and lifestyle changes and people can reduce and eliminate problems like cramps, PMS, endometriosis, PCOS, and common causes of infertility," she told Medical Daily.

Periods are still subjected to misconceptions and myths, so what's true and what’s false?

1. Stress causes a delay in periods.

True: A time of extreme stress can affect your period in a multitude of ways, specifically its length. Often stress works by delaying ovulation; creating longer cycles, as well as making PMS and cramps, or other symptoms worse. Stress affects the functioning of the hypothalamus, which in turn affects the functioning of the pituitary gland, thus affecting the thyroid, ovaries, and adrenal gland. These organs control our hormones, which control ovulation.

Stress from different sources can impact our hormones and how we experience our cycles.

"There is regular stress of working and living in our society, as well as mental health issues, but also things like not getting enough sleep, not having a healthy diet, having too much caffeine, sugar, or alcohol, and various other things can all be perceived as stress on the body," said Macbeth.

2. Too much exercise can lead to an absence of periods.

True: Most women's level of exercise will have a positive effect on their periods and menstrual cycles. However, overdoing exercise can cause a condition known as "amenorrhea" — the lack of a period. This occurs when there are decreased levels of estrogen due to too much exercise. the lack of estrogen can cause osteoporosis, a condition typically associated with old age and characterized by brittle bones.

Intense physical activity combined with decreased caloric intake may cause your menstrual period to cease. Female distance runners are more susceptible to amenorrhea, but this can also develop in women who participate in other sports that emphasize slenderness, like ballet, gymnastics, and figure skating.

3. Close friends sync up periods.

Maybe: The science is 50/50 on the phenomenon known as “menstrual synchrony.” This stems from the belief women who are in close quarters with each other, including roommates, coworkers, friends and family have their periods at the same time. The concept appeared in a 1971 paper published in Nature, which found all undergraduate women in an all-female dorm tended to get their periods at the same time.

However, researchers have tried to mimic the effects of the paper, and found random coincidences, but not enough to make valid claims. In 1992, researcher H. Clyde Wilson found errors in McClintock’s study model, specifically her sample selection and method of determining period start dates at the beginning of her study. He found no significant evidence of menstrual synchrony.

Moreover, women's periods when they're not on birth control might be too inconsistent to truly sync up. It could at the level of chance.

If it were to happen, says Macbeth, "keep in mind these would have to be women who were naturally cycling and not on any form of hormonal birth control."

4. Sex makes you period come regularly.

Maybe: Sex can change the levels of different hormones in the body that affects the menstrual cycle. Some experts believe having sex regularly will help keep periods fairly consistent. During ejaculation, semen — which contain a hormone called prostaglandins — calms the uterus shedding and bleeding. So, when a woman is ready or close to start her period, it is believed her cervix will become low and start to drop; the orgasm of sex will dilate the cervix and cause a vacuum to pull the menstrual blood down.

5. Traveling across time zones affects start and duration of period.

True: Traveling to different time zone makes the body release melatonin as if you're still at home, even if it's broad daylight in a new location. To adjust to the new schedule, the body suppresses the hormone until it's dark again due to the circadian rhythm. This influences hormone release and other important bodily functions, so when your rhythm is off, this impacts hormones such as estrogen and progesterone, which play a key role in ovulation and your menstrual cycle. The lack of spike in estrogen can cause your period to be delayed from its normal start day in the month.

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