Question of the Week
For January 5, 2016
Your answer is correct.
Turner syndromeAnovulatory cyclesProlactinomaPolycystic ovary syndromeVaginal septum
Key Learning Point View Case Presentation
In the first postmenarchal year, the most common cause of irregular menstrual bleeding is anovulatory cycles.
In the first postmenarchal year, the most common cause of irregular menstrual bleeding in an otherwise healthy girl is anovulatory cycles, because the hypothalamic–pituitary–ovarian axis feedback loops are not yet mature. Most menstrual cycles range from 21 to 45 days, last ≤7 days, and require three to six sanitary pads or tampons per 24-hour interval.
Pregnancy is a key cause of amenorrhea and should be tested for, as in this case.
Patients with Turner syndrome typically have hypogonadism with limited breast development and primary amenorrhea. A small percentage may menstruate, but Turner syndrome is much less likely in this patient who has normal height and breast development.
Prolactinomas of the pituitary gland secrete excess prolactin, leading to amenorrhea, oligomenorrhea or, less commonly, galactorrhea. Although possible, a prolactinoma is much less likely than anovulatory cycles to be the cause of this young adolescent’s irregular periods in the first year after menarche.
Young women with polycystic ovary syndrome (PCOS) present with amenorrhea or oligomenorrhea and signs of hyperandrogenism, including hirsutism and acne. Although this patient may end up having PCOS, irregular bleeding in the first postmenarchal year is more likely because of the immature hypothalamic–pituitary–ovarian axis. If the patient’s irregular cycles continue, she can be evaluated for PCOS.
Various types of vaginal septa can initially manifest at the time of menarche. For example, a transverse septum can manifest as hematocolpos, and a longitudinal septum can manifest as bleeding despite tampon use (because the tampon is placed in one half of a divided vagina). However, vaginal septa would not lead to the irregular periods seen in this case.
Natural History of Anovulatory Cycles
Anovulatory cycles are most common in the months after menarche and are typically followed with watchful waiting. However, further workup is recommended for patients who demonstrate any of the following menstrual cycle abnormalities:
- The development of markedly irregular periods after establishment of regular monthly periods
- Amenorrhea lasting >90 days
- Periods lasting >7 days
- Heavy periods requiring frequent pad or tampon changes (soaking through more than one pad or tampon every 1 to 2 hours)
Last reviewed May 2023.
ACOG Committee Opinion No. 651: Menstruation in girls and adolescents: using the menstrual cycle as a vital sign. Obstet Gynecol 2015 Dec; 126:e143. > View Abstract
Gunn HM et al. Menstrual patterns in the first gynecological year: a systematic review. J Pediatr Adolesc Gynecol 2018 Dec; 31:557. > View Abstract