What is secreted from the mother during the initial days of lactation?

Signals from a fully developed foetus and placenta ultimately lead to parturition,which requires the release of:

Signals for parturition originate from

Which of the following is $NOT$ a feature of the dilation stage of parturition?

Give scientific reasons: Doctors advise breastfeeding to mothers for infants.

$A$: 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.