A woman complains of severe abdominal and pelvic pain around the time of menstruation that has gotten worse over the last 5 years. She also complains of pain during intercourse and has tried unsuccessfully to get pregnant for the past 18 months. These symptoms are most likely related to:

Choice A: February 6-7 is incorrect. This is too late for the woman's fertile period, which occurs around the time of ovulation. Ovulation usually happens about 14 days before the next period starts, which would be around January 22 for a 28-day cycle¹.

Choice B:In a 28-day menstrual cycle, ovulation typically occurs around day 14 (counting from the first day of the last menstrual period). Since the first day of the last period is January 8, day 14 falls on January 22. The fertile window consists of the five days leading up to ovulation and the day of ovulation (January 17–22), as sperm can survive in the reproductive tract for up to 5 days, and the egg remains viable for about 24 hours after ovulation.January 22-23 is the most fertile period, with ovulation occurring around January 22 and the egg remaining viable for fertilization on January 23.

Choice C: January 30-31 is incorrect. This is after the woman's fertile period, which ends about a day after ovulation. Ovulation usually happens about 14 days before the next period starts, which would be around January 22 for a 28-day cycle.

Choice D: January 14-15 corresponds to cycle days 7-8, which is too early for ovulation in a typical 28-day cycle. Ovulation generally occurs around day 14 (January 22). The follicular phase (the first half of the cycle) is when the follicles in the ovary mature, and estrogen levels rise to trigger ovulation. At this point (January 14-15), the egg is not yet released, and the uterus is still preparing for ovulation, making conception unlikely.

Choice A reason: This is incorrect because primary dysmenorrhea is menstrual pain that is not associated with any underlying condition. It usually begins with the onset of menstruation and lasts for a few days. It does not cause pain during intercourse or infertility.

Choice B reason: This is correct because endometriosis is a condition where the endometrial tissue that normally lines the uterus grows outside the uterus, such as on the ovaries, fallopian tubes, or pelvic organs. It causes chronic inflammation, scarring, and adhesions that can result in severe pain during menstruation and intercourse, as well as infertility.

Choice C reason: This is incorrect because secondary dysmenorrhea is menstrual pain that is caused by an underlying condition, such as fibroids, pelvic inflammatory disease, or adenomyosis. It usually develops later in life and lasts longer than primary dysmenorrhea. It may or may not cause pain during intercourse or infertility, depending on the condition.

Choice D reason: This is incorrect because PMS stands for premenstrual syndrome, which is a group of physical and emotional symptoms that occur before menstruation. It may include mood swings, irritability, bloating, headaches, or breast tenderness. It does not cause severe pain during menstruation or intercourse, or infertility.