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Illustration by Marta Pucci

Cycle A-Z

How I determine the causes of irregular periods

Dr. Shruthi Mahalingaiah, a physician-scientist and Clue collaborator, talks about the steps she takes with her patients to evaluate irregular periods and PCOS.

by Dr. Shruthi Mahalingaiah, Contributor
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I’m a physician-scientist, specializing in reproductive endocrinology & infertility. I care for women with menstrual disorders, infertility, endometriosis, and fibroids.

In my lab, I study environmental exposures such as air pollution on reproductive health, and the menstrual cycle as an outcome and as a marker for long-term health risks, such as infertility, diabetes, cholesterol problems, cardiovascular disease, and obesity.

If you have irregular periods, your doctor may take many approaches to determine why. Here is what I do.

First steps in determining the cause of irregular periods

When a patient presents with irregular periods, I perform a full detailed history and targeted physical exam. An important starting point is to understand the details of age at menarche, or first menstrual period, and the menstrual cycle pattern, including how long it took to establish regular menstrual cycles if this occurred at all. I ask about any developmental delays, or accelerations in puberty. I also like to understand the lifestyle factors, including sleep patterns, dietary patterns (such as binge eating), working habits, real and perceived stress, exercise habits, tobacco smoking, alcohol use, and substance use.

After this, we discuss any other signs or symptoms that may point to causes of menstrual irregularity, such as milky discharge from the breast, hot flashes, excess facial/body hair, acne, and major weight fluctuations.

After the exam and history, there are blood tests

Depending on the history and physical exam findings, my initial laboratory evaluation of menstrual irregularity usually includes assessment of prolactin, thyroid function, and ovarian function within the pituitary-ovarian axis.

This is because the menstrual cycle is influenced by many organ systems, particularly the endocrine system. Low ovarian function may also be associated with irregular periods. It is important to understand the factors that contribute to irregular bleeding before settling with a diagnosis. There could be structural causes of irregular bleeding, including submucosal fibroids, polyps along the reproductive tract, infection, or abnormalities of the cervix or vagina. If I am concerned about a structural abnormality, the physical exam followed by a pelvic ultrasound helps me with the diagnosis.

How I diagnose PCOS

If there is concern for Polycystic Ovary Syndrome (PCOS) based a patient’s story of irregular periods and an experience of androgen excess (excess facial or body hair, acne, hair thinning on scalp), I evaluate serum androgen levels and perform an ultrasound to assess ovarian shape (called ovarian morphology), regarding how many follicles are present.

Depending on the duration and severity of the menstrual irregularity, I may need to further evaluate the lining of the uterus (endometrium) for endometrial overgrowth (hyperplasia), which is a precursor to endometrial cancer.

Because the causes of menstrual irregularity are varied, the history and physical exam guide my diagnostic and therapeutic approach.

When we have come to a diagnosis of PCOS, I then go through counseling regarding the potential impact of this diagnosis on uterine health, fertility, and future cardiometabolic health. I tailor our discussion to what is most important for the patient at the time of the visit, and continue education at follow up visits after treatments have begun.

Long-term care for irregular periods

I work together with women who want to become pregnant to set short and long term goals for health optimization. In women who do not desire fertility, we focus on health optimization and long-term risk reduction. Depending on the findings from the history, physical exam, and laboratory assessment, I work in conjunction with other specialists, including endocrine and weight management specialists, dermatologists, and counselors.

Endocrinologists provide care for women with primary thyroid and pituitary findings (prolactinomas) that require long-term management. They also provide care, in some practices, for a comprehensive approach to nutrition, weight management, and diabetes.

The dermatologist or skin healthcare provider may offer laser-based therapeutics, electrolysis, or other techniques for unwanted hair on the body. I also collaborate with nutritionists who specialize in PCOS to facilitate a balanced approach to diet so that my patients have the energy they need every day. Some patients work with PCOS-specific health coaches, but that is outside the scope of my practice at this time. Because emotions and behaviors are so important in health, and particularly PCOS, counseling may facilitate stress reduction and awareness of behavior patterns and lead to the potential for healthier choices.

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