A midwife is a professional in midwifery, specializing in pregnancy, childbirth, postpartum, women's sexual and reproductive health (including annual gynecological exams, family planning, menopausal care and others), and newborn care. They are also educated and trained to recognise the variations of normal progress of labor, and understand how to deal with deviations from normal. They may intervene in high risk situations such as breech births, twin births and births where the baby is in a posterior position, using non-invasive techniques. When a pregnant woman requires care beyond the midwife's scope of practice, they refer women to obstetricians or perinatologists who are medical specialists in complications related to pregnancy and birth, including surgical and instrumental deliveries. In many parts of the world, these professions work in tandem to provide care to childbearing women. In others, only the midwife is available to provide care, and in yet other countries many women elect to utilize obstetricians primarily over midwives.