Lactational amenorrhea is effective only up to a maximum period of ........... following parturition.

Which hormone is secreted at the time of parturition?

Which hormone injection is administered by doctors to induce parturition?

Given below are two statements: One is labelled as Assertion $A$ and the other is labelled as Reason $R$ :
Assertion $A$ : Breast-feeding during the initial period of infant growth is recommended by doctors for bringing up a healthy baby.
Reason $R$ : Colostrum contains several antibodies absolutely essential to develop resistance in the newborn baby.
In the light of the above statements,choose the most appropriate answer from the options given below:

Assertion $A :$ Colostrum provides passive immunity to the infant.
Reason $R :$ Colostrum secreted by the mother contains antibodies that protect the infant.

Which hormone is responsible for milk ejection after the delivery of a newborn?