Complex sentence: A Caesarean section is usually performed when a vaginal delivery would put the baby's or mother's life or health at risk, although in recent times it has also been performed upon request for childbirths that could otherwise have been vaginal.
Split into simpler sentences: A Caesarean section is often performed when a vaginal delivery would put the baby's or mother's life or health at risk. Many are also performed upon request for childbirths that could otherwise have been vaginal.