In a woman on subdermal progesterone implant, the menstrual abnormality seen is:
**Core Concept**
The subdermal progesterone implant is a form of long-acting reversible contraception (LARC) that releases a constant dose of progesterone into the bloodstream. This can cause changes in the menstrual cycle due to the progesterone's effect on the endometrium and ovulation.
**Why the Correct Answer is Right**
The subdermal progesterone implant causes amenorrhea (absence of menstruation) in most users due to its suppressive effect on the hypothalamic-pituitary-ovarian axis. Progesterone inhibits the growth of the endometrium, making it unsuitable for implantation, and also suppresses the release of gonadotropin-releasing hormone (GnRH) from the hypothalamus, leading to reduced luteinizing hormone (LH) and follicle-stimulating hormone (FSH) production. This results in anovulatory cycles and amenorrhea.
**Why Each Wrong Option is Incorrect**
* **Option A:** Polymenorrhea refers to frequent menstrual cycles, which is not typically seen with subdermal progesterone implants.
* **Option B:** Oligomenorrhea refers to infrequent menstrual cycles, which is seen in some users but is not the most common menstrual abnormality associated with subdermal progesterone implants.
* **Option D:** Dysmenorrhea refers to painful menstruation, which is not directly related to the use of subdermal progesterone implants.
**Clinical Pearl / High-Yield Fact**
It's essential to note that the subdermal progesterone implant can cause changes in menstrual bleeding, including amenorrhea, and users should be informed about these potential effects before starting treatment.
**Correct Answer: C. Amenorrhea.**