(Verse 1) In the quiet of the womb, where oxygen's low, A foetus learns to thrive, where blood flow is slow. With foetal haemoglobin, it clings to every breath, Oxygen is scarce, but it’s not facing death. A higher heartbeat, 120 to 160 beats, Helps push the blood, to where it’s needed most, Preparing for a world where oxygen's high, The body learns to change, under the dark sky. (Chorus) Adaptation, the body's natural way, From hypoxic nights to the light of day. Catecholamines rise, cortisol in play, Prepares the baby for a brand-new day. (Verse 2) Glycogen builds in the liver and the heart, Stored energy to help with life's new start. In the last trimester, these reserves grow, Ready to release when the time's on show. Surfactant lines the lungs, air sacs to expand, Chloride and sodium shunt, fluids out of hand. Pulmonary vessels dilate, as oxygen flows, Prepares the lungs for life, where the air goes. (Chorus) Adaptation, the body's natural way, From hypoxic nights to the light of day. Catecholamines rise, cortisol in play, Prepares the baby for a brand-new day. (Bridge) Brown fat burns, to keep the body warm, Mitochondria work hard, keeping up the norm. An uncoupling enzyme, heat instead of ATP, Ensures warmth is kept, energy is free. Three shunts close as circulation shifts, The left ventricle grows stronger, the balance drifts. Cardiac output doubles, to meet new demands, The heart works harder, as life expands. (Verse 3) The liver’s still slow, bilirubin stays, Jaundice may appear in those early days. The liver’s immature, just taking its time, As bilirubin builds, in a natural climb. But oxygen’s breath will help clear the way, For the liver to catch up, as the child begins to play. A hungry cry, hormones in control, Driving the instincts, making the baby whole. (Chorus) Adaptation, the body's natural way, From hypoxic nights to the light of day. Catecholamines rise, cortisol in play, Prepares the baby for a brand-new day. (Outro) How do the hormones know it’s time to start? Where’s the clock in this delicate art? The journey’s intricate, so finely planned, From the womb to the world, by nature’s hand.
