Vaginal delivery
A vaginal delivery is the birth of offspring in mammals (babies in humans) through the vagina (also called the "birth canal"). It is the most common method of childbirth worldwide. It is considered the preferred method of delivery, with lower morbidity and mortality than Caesarean sections (C-sections). Epidemiology. United States. 70% of births in the United States in 2019 were vaginal deliveries. Global. 80% of births globally in 2021 were vaginal deliveries, with rates varying from 95% in sub-Saharan Africa to 45% in the Caribbean. Benefits of vaginal delivery. Mother. Benefits for the mother include Infant . Benefits for the infant include: Types of vaginal delivery. Different types of vaginal deliveries have different terms: A "normal vaginal delivery" ("NVD") is defined as any vaginal delivery, assisted or unassisted. Stages of labor. Labor is characterized by uterine contractions which push the fetus through the birth canal and results in delivery. Labor is divided into three stages. Risks and complications of vaginal delivery. Complications of vaginal delivery can be grouped into the following criteria; failure to progress, abnormal fetal heart rate tracing, intrapartum hemorrhage, and post-partum hemorrhage. "Failure to progress" occurs when the labor process slows or stops  entirely, indicated by slowed cervical dilation. Factors that place a woman's pregnancy at higher risk include advanced maternal age, Premature Rupture of Membranes (PROM) and induction of labor. Oxytocin, a uterotonic agent, can be administered to augment labor. Cesarean section is also commonly considered when the pregnancy fails to progress. "Abnormal fetal heart tracing" suggests that the fetus' heart rate has slowed during labor due to head compression, cord compression, hypoxemia or anemia. This issue is often resolved by discontinuing labor augmenting agents such as oxytocin. If the abnormal fetal heart rate persists, a cesarean section is indicated. "Intrapartum  hemorrhage" is characterized by the presence of copious blood during labor. The bleeding may be due to placental abruption, uterine rupture, placenta accrete, undiagnosed placenta previa, or vasa previa. Cesarean section is indicated. "Post-partum hemorrhage" is defined by the loss of at least 1,000 mL of blood accompanied with symptoms of hypovolemia within 24 hours after delivery. Typically, the first symptom is excessive bleeding accompanied by tachycardia. Significant loss of blood may also result in hypotension, nausea, dyspnea, and chest pain. It is estimated that between 3% to 5% of women giving birth vaginally will experience post-partum hemorrhage . Risk factors include fetal macrosomia, pre-eclampsia, and prolonged labor. Prevention consists of administering oxytocin (Pitocin) at delivery and early umbilical cord clamping. Post-partum hemorrhage is usually attributed to uterus atony, when the uterus fails to contract after delivering the baby. Contraindications to vaginal delivery. Spontaneous vaginal delivery at term is the preferred outcome of pregnancy, and according to the International Federation of Gynecology and Obstetrics, will be recommended if there are no evidence-based clinical indications for cesarean section. However, there are some contraindications for vaginal delivery that would result in conversion to cesarean delivery. The decision to  switch to cesarean delivery is made by the health care provider and mother, and is sometimes delayed until the mother is in labor. "Breech birth" presentations occur when the fetus' buttocks or lower extremities are poised to deliver before the fetus' upper extremities or head. The three types of breech positions are footling breech, frank breech, and complete breech. Breech positions can result in conversion from vaginal to cesarean delivery because it is more difficult for the baby to deliver through the birth canal, there is a risk for cord prolapse, and there is a slightly elevated risk for birth  defects of breech babies. "Complete placenta previa" occurs when the placenta covers the opening of the cervix. If placenta previa is present at the time of delivery, vaginal delivery is contraindicated because the placenta is blocking the fetus’ passageway to the vaginal canal. "Herpes simplex virus with active genital lesions or prodromal symptoms" is a contraindication for vaginal delivery so as to avoid mother-fetal transfer of HSV lesions. "Untreated human immunodeficiency virus (HIV) infection" is a contraindication for vaginal delivery to avoid mother-fetal transfer of human immunodeficiency virus.