How do oral contraceptives, injections, implants, and skin patches prevent egg maturation and release?
How do oral contraceptives, injections, implants, and skin patches prevent egg maturation and release?
Answer
Oral contraceptives, injections, implants, and skin patches are all forms of hormonal contraception that primarily prevent egg maturation and release through the regulation of hormones in the body. Here’s how each method functions:
Oral Contraceptives
Combined Oral Contraceptives (COCs)
- Mechanism: COCs contain both estrogen and progestin. They inhibit ovulation by suppressing the secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the pituitary gland. Without the LH surge, which triggers ovulation, an egg does not mature or get released from the ovaries. Additionally, these pills thicken cervical mucus, making it more difficult for sperm to enter the uterus and fertilize an egg.
Progestin-Only Pills (Mini-Pills)
- Mechanism: These pills primarily work by thickening cervical mucus and thinning the uterine lining. While they can also suppress ovulation, this effect is not as consistent as with COCs. The thickened mucus acts as a barrier to sperm, while the altered endometrial lining reduces the likelihood of implantation if fertilization occurs.
Injections
Depo-Provera
- Mechanism: This injectable contraceptive contains progestin and is administered every three months. It works by preventing ovulation through suppression of FSH and LH, similar to COCs. Additionally, it thickens cervical mucus and thins the uterine lining, further reducing the chances of pregnancy.
Implants
Hormonal Implants
- Mechanism: Implants release progestin continuously over a period of several years. They prevent ovulation by inhibiting the hormonal signals necessary for egg maturation and release. Like other hormonal methods, they also thicken cervical mucus and thin the endometrial lining to prevent implantation.
Skin Patches
Transdermal Patch
- Mechanism: The patch delivers a combination of estrogen and progestin through the skin into the bloodstream. Similar to COCs, it prevents ovulation by suppressing FSH and LH levels. The patch also thickens cervical mucus and alters the endometrial lining to prevent implantation