Q.32.. - Biology

Question

Oral contraceptive pills work by delivering synthetic progestins to a woman every day. Describe why this is an effective method of birth control. 

Step-by-Step Solution

Answer

Progestins exert their contraceptive effects by inhibiting the secretion of luteinizing hormone (LH), follicle-stimulating hormone (FSH), and gonadotropin-releasing hormone (GnRH) by the pituitary gland and hypothalamus, respectively. In order to inhibit ovulation, the suppression alters the menstrual cycle. 

Step 1: Introduction

• Progestins exercise their contraceptive effects by suppressing the secretion of gonadotropin-releasing hormone (GnRH) by the hypothalamus and luteinizing hormone (LH) and follicle-stimulating hormone (FSH) by the pituitary gland. 
• The suppression changes the menstrual cycle to subdue ovulation.

Step 2: Explanation

• There is a thickening of the mucus in the cervix, which makes it difficult for sperm to enter the uterine membrane and fertilize the egg. 
• Progestin hinders ovulation, but it does not do so consistently.
• Progestins also offer other advantages by secondary mechanisms such as slowing tubal motility by impairing the fallopian tube and prompting endometrial atrophy.