The progestin present in Sino-Implant II is
**Core Concept**
Sino-Implant II is a type of contraceptive implant that contains a synthetic progestin hormone. The progestin in this implant is responsible for preventing ovulation, thickening cervical mucus, and altering the endometrium, making it less receptive to implantation.
**Why the Correct Answer is Right**
The progestin present in Sino-Implant II is Medroxyprogesterone acetate (MPA). MPA is a long-acting progestin that is released from the implant over a period of time, providing effective contraception. It works by inhibiting the release of gonadotropin-releasing hormone (GnRH) from the hypothalamus, which in turn reduces the secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the anterior pituitary gland. This reduction in LH and FSH secretion prevents ovulation, making it difficult for a fertilized egg to implant in the uterus.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not specified, but it is not the correct answer.
* **Option B:** This option is also not specified, but it is not the correct answer.
* **Option C:** This option is also not specified, but it is not the correct answer.
**Clinical Pearl / High-Yield Fact**
It's essential to note that Sino-Implant II is a non-biodegradable implant, meaning it remains in place for up to 5 years, providing long-term contraception.
**Correct Answer:** C. Medroxyprogesterone acetate (MPA)