This 3D medical animation demonstrates the first stage of labor. During a vaginal childbirth, the first stage of labor lasts about 12 to 19 hours,
and starts when your baby settles lower into your pelvis. In response, your cervix begins to efface, or become thinner (pause), and dilate, or widen. During this time, you may feel strong, regular contractions occurring every 5 to 20 minutes; and lower back pain and cramping that doesn’t go away. You may see a brownish or reddish mucus discharge, which could be the mucus plug at the opening of your cervix falling out. Your water may break, which can either be a large gush of fluid or a continuous trickle. If you experience any of these symptoms, contact your doctor or midwife to see if you should go to the hospital.