Obstetrics & Gynaecology – MCQ 56 – Mechanisms of action of oral contraceptive pill

All of the following mechanisms of action of oral contraceptive pill are true, except:
A. Inhibition of ovulation
B. Prevention of fertilization
C. Interference with implantation of fertilized ovum
D. Interference with placental function

Correct answer : D. Interference with placental function

Mechanism of action of oral contraceptive pills:

  • Prevents ovulation by inhibition of LH surge
  • Induce atrophic changes in endometrium, preventing nidation
  • Thickening of cervical mucus preventing entry of sperms
  • Increases tubal motility, so that the fertilized egg reaches uterine cavity before the endometrium is receptive for implantation
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