On the basis of the understanding of the cellular mechanisms of thyroid hormone action on the heart and cardiovascular system, it is possible to explain the changes in cardiac output, cardiac contractility, blood pressure, vascular resistance, and rhythm disturbances that result from thyroid dysfunction.
Last updated: July 2015. Tummy time is essential from day one to help your baby grow strong â even if your baby fusses and cries when you put him on his belly. Experts find that babies who don't spend time face-down often have some delays in their development of motor skills.
When is it safe to let my baby sleep on his tummy? To reduce the risk of sudden infant death syndrome (SIDS), experts recommend that you place your baby on his back when you put him down to sleep during his first year. The risk of SIDS peaks between 1 and 4 months of age but remains a threat until babies are 12 months. Once your baby is strong enough to roll from back to front and front to back by himself, you don't need to worry about him rolling onto his stomach during sleep.