Corpus luteum in pregnancy has a long life. However if fertilisation does not take place, it remains active only for 10-12 days. Explain.

Explanation

This is because of a neural signal given by the maternal endometrium to its hypothalamus in presence of a zygote to sustain the gonadotropin (LH) secretion, so as to maintain the corpus luteum as long as the embryo remains there. In the absence of a zygote , therefore the corpus luteum can not be maintained longer.