Menstrual Synchrony: Female Phenomenon or Fake Science?
Alicia Armeli


If you’ve ever had female roommates or a house full of sisters, you’re probably well aware of the bond we all share surrounding the comings and goings of Auntie Flow. A rite of passage, menstruation provides a unique sisterhood.

But could our periods be connecting us ladies on a level we may not even be aware of? Menstrual synchrony—or the theory that women who spend a lot of time together also get their periods together—has been studied for decades. And contrary to popular belief, many researchers place this so-called phenomenon on the same level as bunk science.

The idea of menstrual synchrony started back in 1971 when University of Chicago psychologist Martha McClintock observed 135 girls living in a dorm of a suburban women’s college.1 Three times throughout the academic year, McClintock interviewed the girls about their period start dates and social interactions.

Results published in Nature showed that girls who spent the most time together—either as roommates or closest friends—were more likely to start their periods around the same time. This synchronicity, labeled “the McClintock Effect,” was seen to happen more so in April as the academic year unfolded—and more time was spent together amongst girls—versus early on in October. McClintock attributed these results to pheromones or body chemicals humans unknowingly give off that influence the behavior and physiology of other humans in close proximity.

Following this study, other researchers tried to verify McClintock’s results by studying menstruation in other female groups, including women living in dorms, cohabitating lesbian couples, tribal women, as well as other mammals like chimpanzees.2

As a whole, results from these studies remained inconsistent. It seemed that for every study supporting menstrual synchrony, there was another study that refuted it. Several researchers concluded that menstrual synchrony was probably due to coincidence or “pure happening” rather than female phenomenon.2

Probably one of the most fascinating attempts to prove menstrual synchrony exists emerged in 1980. Russel, Switz, and Thompson swabbed cotton pads soaked with an alcohol-underarm perspiration mixture obtained from a female donor under the noses of participating women to see if the smell of pheromones changed the onset of menstruation.3 Results showed a significant shift in the timing of the participants’ periods—a reduction in the average start date from 9.3 days to 3.4 days—that reflected more closely the cycle of the donor.

Further work by McClintock found that women exposed to female donor underarm secretions resulted in a change in menstrual cycle length—but results have been questionably significant.4

Menstrual synchrony may exist, but it could be attributed to other factors. A study led by Jhanfar et al. found that although specific pheromones released from the underarms weren’t related to menstrual synchrony, things like pheromones located in the vagina that are given off by way of menstrual blood and vaginal discharge might play a role.5 Other studies have found that more important factors influencing menstrual cycle differences are body weight and period irregularity, not so much pheromones or social interactions between women.6

Overall, the evidence to support menstrual synchrony is weak and more research is needed to solidify its existence and which factors, if any, influence it. However, this doesn’t mean that this biological commonality can’t serve as a time for women to connect with themselves and each other.


  1. McClintock, M. (1971). Menstrual synchrony and suppression. Nature, 229: 244-245.
  2. Matei, C., Tampa, M., Sarbu, I., et al. (2015). Menstrual synchronizing: myth or reality? Gineco EU, 11(39): 31-32.
  3. Russell, M., Switz, G., & Thompson, K. (1980). Olfactory influences on the human menstrual cycle. Pharmacology, Biochemistry, and Behavior, 13(5): 737-738.
  4. Stern, K., & McClintock, M. (1998). Regulation of ovulation by human pheromones. Nature, 392:177-179. doi:10.1038/32408.
  5. Jahanfar, S., Awang, C., Rahman, R., et al. (2007). Is 3α−androstenol pheromone related to menstrual synchrony? Journal of Family Planning and Reproductive Health Care, 33(2): 116-118.
  6. Ziomkiewicz, A. (2006). Menstrual synchrony: fact or fiction? Human Nature, 17(4): 419-432. doi:10.1007/s12110-006-1004-0.

UAE: One More Reason to Celebrate National Without a Scalpel Day
Alicia Armeli

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What do heart disease, stroke, aneurysms, and uterine fibroids have in common? They’re just a handful of conditions that can now be treated without surgery. In honor of this progress, The Interventional Initiative made today annual National Without a Scalpel Day.

“In 2015, we established this day on the National Day Calendar as part of our non-profit’s broader mission to raise awareness about the value of Minimally Invasive Image-guided Procedures (MIIPs),” The Interventional Initiative explains. “The first MIIP—an angioplasty—was performed on this day in 1964 by Dr. Charles Dotter. This angioplasty opened a blocked blood vessel, allowing the patient to avoid leg amputation surgery. She left the hospital days later with only a Band-Aid.”

The same “with only a Band-Aid” mantra has now expanded into other areas of treatment and is sung among interventional radiologists and their patients worldwide—especially when these patients are women seeking nonsurgical relief for their uterine fibroids.

Uterine artery embolization (UAE) is one such treatment with a similar rich history. In 1974, French neuroradiologist Jean-Jacques Merland used UAE to treat a woman with fibroid-related heavy menstrual bleeding.1 After this success, Merland worked with gynecologist Jacques Ravina and found that UAE also controlled blood loss related to myomectomy—the surgical removal of fibroids—and decreased the need for blood transfusions.1

In 1993, Merland and Ravina went on to conduct a multicenter trial studying UAE’s safety and efficacy in treating symptomatic uterine fibroids. Published in the 1995 Lancet, their results showed UAE to completely resolve fibroid-related symptoms in nearly 70% of patients.2 Since then, most studies show favorable outcomes with only 20-30% of women requiring retreatment 5 years post-UAE—a statistic similar to that of myomectomy.3

But unlike surgery, UAE only requires a small nick in the wrist or upper thigh. An interventional radiologist inserts a slim tube called a catheter and, under real time imaging, guides it into the arteries that supply fibroids with blood. Once reached, tiny particles called embolics are injected to block blood flow to the fibroids, causing them to shrink and symptoms to subside.

Even though uterine fibroids are noncancerous growths, they can trigger severe symptoms like heavy menstrual bleeding, pelvic pain and pressure, and incontinence. Symptoms like these affect one out of every four women with fibroids, frequently causing them to seek treatment.4 “There are MIIPs to treat a wide range of diseases. Unfortunately, most people have never heard of them,” The Interventional Initiative says. “A growing body of evidence suggests that people who are more informed of their treatment options have better outcomes.”

Now interchangeably labeled uterine fibroid embolization (UFE), the procedure remains the same but with added improvements in pain management and quality of embolics used. What’s more, this outpatient procedure offers women a faster recovery time, along with fewer complications in comparison to surgery.5 And if anything, the ability to walk away with nothing more than a Band-Aid is pretty great too.

ABOUT THE AUTHOR   Alicia Armeli is a Health Freelance Writer and Editor, Registered Dietitian Nutritionist, and Certified Holistic Life Coach. She has master’s degrees in English Education and Nutrition. Through her writing, she empowers readers to live optimally by building awareness surrounding issues that impact health and wellbeing. In addition to writing, she enjoys singing, traveling abroad and volunteering in her community.




  1. Gonsalves, C. (2008). Uterine artery embolization for treatment of symptomatic fibroids. Seminars in Interventional Radiology, 25(4): 369-377. doi: 10.1055/s-0028-1103001.
  2. Ravina, J., Herbreteau, D., Ciraru-Vigneron, N, et al. (1995). Arterial embolisation to treat uterine myomata. Lancet, 346(8976): 671-672.
  3. Spies, J. (2016). Current role of uterine artery embolization in the management of uterine fibroids. Clinical Obstetrics and Gynecology, 59(1): 93-102. doi: 10.1097/GRF.0000000000000162.
  4. Islam, M., Segars, J., Castellucci, M., & Ciarmela, P. (2017). Dietary phytochemicals for possible preventive and therapeutic option of uterine fibroids: Signaling pathways as target. Pharmacological Reports, 69(1): 57–70. doi: 10.1016/j.pharep.2016.10.013.
  5. Memtsa, M., & Homer, H. (2012). Complications associated with uterine artery embolisation for fibroids. Obstetrics and Gynecology International, 2012; 2012:290542. doi: 10.1155/2012/290542.


Does Hysterectomy Increase My Risk of Thyroid Cancer?
Alicia Armeli


Thyroid cancer is the fifth most common cancer among women and disproportionately affects us more than men.1 Recent studies have shown that hysterectomy—the surgical removal of the uterus and the second most common gynecological operation in the US among women of reproductive age—may be a risk factor for developing thyroid cancer.2,3,4,5

Over a decade ago, a Finnish study showed that having a hysterectomy increased the risk of thyroid cancer during the first 2 years following surgery.3 In 2016, the International Journal of Cancer published a Swedish study agreeing with these results, linking hysterectomy for the treatment of non-cancerous conditions with cancer later on in life.4

To better understand the link between hysterectomy and thyroid cancer, the scientific community has looked at other factors such as estrogen. Estrogen is thought to encourage the growth of non-cancerous and cancerous thyroid cells, prompting researchers to examine how removing the ovaries during surgery or hormone replacement therapy affects a woman’s risk of thyroid cancer.1,5

A 2016 US study examined this potential relationship and found hysterectomy to be a risk regardless of keeping or sparing the ovaries. “Our large prospective study observed that hysterectomy, regardless of oophorectomy [removal of the ovaries] status, was associated with increased risk of thyroid cancer among postmenopausal women,” writes Dr. Juhua Luo, PhD, Associate Professor of Epidemiology and Biostatistics at Indiana University Bloomington in Bloomington, Ind., and lead researcher of the study.5

Luo and her team observed 127, 566 postmenopausal women ages 50-79 in 40 clinics across the US who were part of the Women’s Health Initiative study that took place from 1993-1998. Each woman participating in the study reported if she had a hysterectomy with or without removal of the ovaries. Researchers used this information along with their medical records and confirmed any cases of thyroid cancer. The researchers followed up for an average of 14.4 years.

Results published in The Journal of Clinical Endocrinology and Metabolism showed that 36.7% of women had a hysterectomy and 55% had both their fallopian tubes and ovaries removed. After analyzing the data, researchers saw 344 cases of thyroid cancer. In comparison to women who didn’t have a hysterectomy, those who underwent surgery had a significantly higher risk of being diagnosed with thyroid cancer—regardless of whether ovaries were removed or spared. This risk was seen to increase if the surgery was done before age 50.

What’s more, hormone replacement therapy was seen to reduce the risk of thyroid cancer among women who had hysterectomy alone. This trend between hormone therapy and cancer risk wasn’t significant among women without hysterectomy or those with hysterectomy and fallopian tubes and ovaries removed. “Our data did not support the hypotheses that exogenous estrogen is a risk factor or that estrogen deprivation is a protective factor for thyroid cancer,” Luo and her team note.5

Given these results, does hysterectomy itself contribute to the risk of developing thyroid cancer?

At this time, more research is needed. It’s not clear if hysterectomy is a risk factor or if the bleeding conditions that lead to a hysterectomy have a common connection with thyroid cancer.3,5 If hysterectomy is necessary, it shouldn’t be avoided despite its possible link to cancer. However, talking to your doctor about your medical history and learning the signs and symptoms of thyroid cancer are the first steps to understanding your own personal risk.

ABOUT THE AUTHOR   Alicia Armeli is a Health Freelance Writer, Editor, Registered Dietitian Nutritionist, and Certified Holistic Life Coach. She has master’s degrees in English Education and Nutrition. Through her writing, she empowers readers to live optimally by building awareness surrounding issues that impact health and wellbeing. In addition to writing, she enjoys singing, traveling abroad and volunteering in her community.



  1. American Thyroid Association. (2016). Clinical Thyroidology for the Public. Retrieved December 30, 2016, from


  1. Centers for Disease Control and Prevention. Data and Statistics: Hysterectomy. Retrieved December 30, 2016 from


  1. Luoto, R., Grenman, S., Salonen, S., & Pukkala, E. (2003). Increased risk of thyroid cancer among women with hysterectomies. American Journal of Obstetrics and Gynecology, 188(1): 45-48.


  1. Altman, D., Yin, L., & Falconer, H. (2016). Long-term cancer risk after hysterectomy on benign indications: Population-based cohort study. International Journal of Cancer, 138(11): 2631-2638. doi: 10.1002/ijc.30011.


  1. Luo, J., Hendryx, M., Manson, J., Liang, X., & Margolis, K. (2016). Hysterectomy, oophorectomy, and risk of thyroid cancer. The Journal of Clinical Endocrinology and Metabolism, 101(10): 3812-3819.