The signals for parturition originate from:

The correct answer is Option (1) → Fully developed foetus and placenta

Parturition is the process of giving birth to the baby at the end of pregnancy. It is brought about by a complex neuroendocrine mechanism, that is, by nerves and hormones working together.

(1) Fully developed foetus and placenta — Correct. The signals for parturition start from the fully developed foetus and the placenta. They cause mild contractions of the uterus, called the foetal ejection reflex.

(2) Uterine contractions — Incorrect. Uterine contractions are the result of the signals, not their source. The mild contractions set off the release of oxytocin, which then makes the contractions stronger.

(3) Maternal pituitary — Incorrect. The mother’s pituitary releases oxytocin only after the foetal ejection reflex has started. It responds to the signal; it does not start it.

(4) Ovary — Incorrect. The ovary does not send the signal for parturition.

NCERT Extract:
Parturition and Lactation –