During pregnancy, your baby has been kept warm, cosy and protected in your womb. She has received food and oxygen via the placenta without having to make any effort herself. She has been gently rocked as you walk and, hearing to your voice, she has gradually learnt to recognise it. Occasionally, her circulation has been flooded with stress hormones when you have had a fright or faced difficulties in your life. However, in general, she has been very content!
When labour starts, your baby is subjected to a whole range of new, possibly frightening, and almost certainly stressful experiences. The walls of the womb start closing in on her regularly, first gently and then with increasing strength. She hears your voice in distress. Her head is pressed down on the hard ring of the cervix which yields gradually in front of her.
As labour progresses, your baby is propelled deeper into the pelvis and the action of the womb and the muscles of the pelvic floor push her chin firmly down onto her chest. At the deepest point of the pelvis, her head is turned sideways so that she is in the best position to be born. With her feet, she kicks against the hard muscle at the top of the womb to push herself out into the world.
As she is born, she feels the hard pubic bone on the back of her head, and then the softer tissues of the perineum sweeping over her face. From the darkness of the womb, she is born into a room probably lit with bright lights, and full of strange noises.
Birth forces her to take a breath and as the chest expands, air is sucked into the lungs, which have been massaged by contractions throughout labour. The placenta's life support function is over and baby's blood transfuses back to the baby along the cord so she can support herself independently. The cord is cut and because it has no nerve supply neither you or the baby feel this. The relief when you enclose her in your arms and she recognises your smell and your voice must be enormous. No wonder she wants to stay close to you.