Mittelschmerz—or ovulation pain, as it is commonly known today—is a benign preovulatory lower abdominal pain that occurs midcycle (between days 7 and 24) in women. Mittelschmerz may affect over 40% of women of reproductive age, and it occurs almost every month in these patients. It generally does not begin until a few years following menarche when the true ovulatory cycles become established. Pain varies in severity from a mild ache to agonizing pain and is generally felt near the ovaries on the same side as the developing follicle. Mittelschmerz has been found to coincide with the peak in plasma luteinizing hormone (LH) levels when the follicle is enlarging and has not yet ruptured; however, mittelschmerz is unlikely due to follicular distention. Rather, the LH rise increases ovarian perifollicular smooth muscle contractility via a prostaglandin-mediated pathway, which may produce the pain.
Mittelschmerz most often presents as an acute lower quadrant (usually right-sided) pain ranging from a mild ache to intense pain. Along with several other gynecologic pathologies, mittelschmerz may present similarly to acute appendicitis, leading to misdiagnosis and unnecessary surgery. Mittelschmerz merits consideration before diagnosing appendicitis in young women of reproductive age. Mittelschmerz should also be given adequate attention from all medical providers so that it can be easily recognized and diagnosed. Interprofessional communication and awareness can help improve patient outcomes and reduce patient harm.
Women who experience mittelschmerz may not experience it every month, and they may not recognize that it is related to their ovulatory cycles. Mittelschmerz can present as pain in either iliac fossa, and it will generally be on the same side as the developing follicle. The pain usually ceases within three to twelve hours, although patients who have undergone ovarian surgery may experience mittelschmerz that persists until the onset of menstruation. The patient may also report mild backache. Mittelschmerz may improve with oral contraceptive use. The knowledge that mittelschmerz coincides with peak luteinizing hormone (LH) levels may be useful in identifying the most fertile days of the ovulatory cycle and potentially aid in family planning.
In female patients of reproductive age, gynecological pathologies can often be mistaken for acute appendicitis. Gynecologic pathologies and acute appendicitis both present with Rovsing’s sign, defense, elevated leukocyte count, and elevated temperature in a statistically significant number of cases. When working with this population, healthcare teams need to consider the probability of gynecological pathologies when working up a case of acute abdominal pain—doing so can improve patient outcomes and reduce patient harm. [Level 1]
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