Question

Hormone causing vigorous contraction of myometrium to initiate parturition is ________ .

• A. hCG
• B. ACTH
• C. corticosteroids
• D. oxytocin

Hint:

Labour hormone: Oxytocin $\rightarrow$ Uterine contraction

Answer 1

The Correct Option is D

Concept: Parturition (childbirth) is regulated by hormonal interactions between foetus and mother.
• Oxytocin is released from posterior pituitary.
• It stimulates strong uterine (myometrial) contractions.

Step 1: Understand role of oxytocin.
Oxytocin increases frequency and strength of uterine contractions.

Step 2: Positive feedback mechanism.
Stretching of cervix $\rightarrow$ Oxytocin release $\rightarrow$ Stronger contractions.

Step 3: Analyze options.
• (A) hCG: Maintains pregnancy
• (B) ACTH: Adrenal stimulation
• (C) Corticosteroids: Initiate signals but not direct contraction
• (D) Oxytocin: Directly causes contraction (correct)

Step 4: Conclusion.
Thus, oxytocin is responsible for uterine contractions. Final Answer: Option (D)