Which of the following are the hypotheses for the onset of Labor?

Which of the following are the hypotheses for the onset of Labor?

  1. Uterine distension
  2. Activation of fetal hypothalamic-pituitary-adrenal axis
  3. Increase in prostaglandins
  4. Increase in serum calcium levels
    Select the correct answer using the code given below:
    (a) 1, 2 and 3
    (b) 1, 2 and 4
    © 1 and 3 only
    (d) 2, 3 and 4

Ans D