Instinctive resuscitation of the newborn rat.

Pregnant albino rats were observed during labour and delivery to determine whether they assist the newborn rat to breathe, and if so, in what way. The maternal rat actively resuscitates and assists the newborn. This appears to involve four distinct stages. (1) Cleaning of airways. Immediately after birth, the maternal rat holds the head of the newborn with both paws, cleans and sucks the nares and the mouth of the newborn. She then cuts the umbilical cord and eats the placenta. (2) Assistance. When necessary, she presses the pup's chest with one paw for a few seconds, licks the spine from caudal to cervical region, which causes extension of the body and expansion of the chest, or bites the tail, which makes the newborn squeak. (3) Rest. The newborn is then left alone for as long as 20 min while the mother is delivering the rest of the litter. (4) Stimulation. This involves periodic pushing, rolling, licking, and biting of the newborn. Stillbirths are left alone and not attended. If pups are removed from their mother immediately after birth and prevented from being cleaned, they develop respiratory distress, with mouth breathing, gasping, chest retraction, and cyanosis. This model in nature emphasizes the importance of cleaning the upper airways of the newborn.