Postnatal preventive care is as important as prenatal care. The postnatal period lasts for 6-8 weeks after the baby is born. During this period a new mother goes through several physical and emotional changes while learning to care for her newborn. The most important elements of postnatal care are enough rest, good nutrition and vaginal care. At about six weeks post-birth, you may have a postnatal screening where your doctor will check for general physical and mental well-being.