The length of a menstrual cycle can vary throughout life due to a variety of factors. In my case, periods only lasted a few days for decades. Yet, I started noticing a change after I turned forty—they started getting shorter. It wasn't until I finally finished a box of 16 tampons which I had purchased a year prior, that I realized a change. "Irregular periods should be evaluated by your healthcare provider," Dr. Sara Twogood, board-certified obstetrician and gynecologist, says. However, "it is normal for menstrual cycle length to fluctuate a bit."
I spoke to two OBGYNs to learn about the potential reasons for my periods getting shorter. It turns out there is a variety of possible factors that may impact the duration of a menstrual cycle. Keep reading to find out what may be causing shorter periods.
Age
"As a woman gets older, her menstrual cycles may become shorter," Dr. Hack explains. "This often becomes apparent in our 40s, especially in the years leading up to menopause." In my case, I am experiencing several symptoms of perimenopause that point to this as being a factor (for instance, waking up at 5 a.m. for no reason).
Still, "it can be normal for period flow to vary from month to month and also change over time," Dr. Twogood adds.
Hormonal Contraception
Hormonal contraception such as birth control pills and IUDs may lead to lighter or shorter periods. "Hormonal contraception (progestin IUD, birth control pills) can make a period lighter," Dr. Twogood says. This is because any hormonal change may affect your period. "The menstrual cycle is controlled by hormones and any changes in these hormones can affect the length of the menstrual period," Dr. Hack adds.
Medication
"Certain medications, such as birth control pills, can affect hormone levels and lead to shorter menstrual periods," Dr. Hack says. Other types of medications or treatments such as steroids and chemotherapy can also lead to shorter periods. "The period may return to its typical length once the medication is stopped," Dr. Hack notes.
Stress
Stress—especially if it is chronic—can have an impact on various aspects of our lives and periods are one of them. "Stress can disrupt the hormonal balance in the body, leading to shorter menstrual periods," Dr. Hack says. Too much stress creates an abundance of cortisol, which may disrupt how hormones typically function.
Exercise
Periods of time during which you exercise more intensely than usual may lead to shorter periods. "Regular, intense exercise can also affect hormones and lead to shorter menstrual periods," Dr. Hack says. "If someone is undergoing strenuous training, their period may disappear altogether."
Rapid Weight Change
Rapidly losing or gaining weight can affect the length of periods. "Rapid weight loss or gain can affect hormone levels and lead to shorter menstrual periods," Dr. Hack says. The body may produce more or less estrogen as a response to changes in weight, which may offset your usual cycle.
Pregnancy and Postpartum
"During pregnancy, menstrual periods will stop and can be shorter upon return of the period," Dr. Hack says. "In addition, some women may experience implantation bleeding, which occurs when a fertilized egg implants in the uterine lining. This bleeding happens around the time of the expected period, however [it] typically only lasts one to two days."
Breastfeeding
Breastfeeding typically leads to shorter periods. They often return to their typical length three to six months after breastfeeding, although it may take longer.
PCOS
Polycystic ovarian syndrome ( PCOS) is a condition affecting hormonal balance. It causes the body to develop cysts in the ovaries containing premature eggs. It can affect menstrual cycles in several ways. "Polycystic ovary syndrome (PCOS) can also affect hormone levels and lead to shorter menstrual periods. These periods may also be infrequent," Dr. Hack says.
Thyroid Disorder
The thyroid is a small organ located in the neck and is often referred to as the "master gland" of the endocrine system. When it's function is disrupted, it may lead to hormonal imbalance. Shorter periods may be due to hypothyroidism (when your thyroid is too slow), hyperthyroidism (when it's too fast) or Hashimoto's disease (an autoimmune disorder).
Premature Ovarian Insufficiency
Premature ovarian insufficiency (or POI) refers to the instance in which your ovaries stop producing eggs before the standard age of menopause. In this instance, ovaries stop producing estrogen and progesterone. It may lead to early menopause. POI may also lead to irregular or light periods, as well as them stopping entirely. It occurs in about 1% of menstruators.
Uterine Scarring
Uterine scarring can occur due to medical procedures, inflammation, endometriosis or sexually transmitted infections like chlamydia. It may lead to shorter periods because of abnormal blood supply to the uterus. Uterine scarring may also lead to infertility.
The Final Takeaway
There are several reasons why your period may be shorter—from stress to hormonal contraception and PCOS. It is normal for menstrual cycles to fluctuate in length. However, if you notice a drastic change or are worried about a potential underlying condition, consult your medical provider.
