Which hormone inhibits the menstrual cycle in females during the period of lactation?

$A$: Colostrum is a very efficient means of transferring immunity to a newborn.
$R$: $IgM$ from mother's milk protects the baby from the respiratory infection usually affecting in young age.

Which hormone is responsible for the secretion of milk after the birth of a child?

Which of the following hormones induces milk ejection in females when the baby is suckling?

The signals for parturition originate from the fully developed foetus and the placenta, which induce mild uterine contractions known as:

The contraction of the uterus at the time of childbirth is stimulated by $........$.