Miscarriage is the loss of a pregnancy during the first trimester and occurs in about 25% of pregnancies. Warning signs of miscarriage include cramping, back pain, vaginal bleeding or discharge. There are different types of miscarriage such as threatened, inevitable, complete, and missed. Causes can include placental problems, womb abnormalities, and lifestyle factors like smoking, drinking, or drug use. To help prevent miscarriage, women should avoid these lifestyle factors, eat nutritious foods, maintain a healthy weight, and avoid infections.