Childbirth
Childbirth, or labor and delivery, is when a woman gives birth to a baby. Labor has three stages. The first stage of labor has two phases: latent and active. The second stage of labor is when the baby is born while the third stage of labor is when the placenta is delivered.
First Stage of Labor
Irregular contractions are felt during the latent phase of labor. The contractions will slowly become more regular and pain is minimal. The cervix will dilate and efface up to 4 centimeters during the latent phase of labor. First time mothers will on average labor 8 hours during the latent phase. Mothers who have borne previous children typically have shorter labor during the latent phase. Towards the end of this stage a woman will enter the transition phase. During this part of labor the cervix will continue to dilate to 10 centimeters. This is probably the most painful part of the labor process.
Second Stage of Labor
The cervix is fully dilated and the woman begins to push to deliver the baby. This phase of labor can last up to two hours. The baby is delivered at the end of the second stage of labor. The umbilical cord is cut by the doctor once the delivery is finished.
Third Stage of Labor
The placenta is delivered during the third stage of labor. Usually this phase of labor takes between 5 to 20 minutes.
Definitions
Cervical Dilation
Measurement of the cervix is recorded from 0 to 10 centimeters. The cervix is considered complete when it reaches 10 centimeters.
Effacement
The cervix shortens in preparation for birth. The normal uneffaced average cervical length is between 3.5 to 4.0 centimeters.
Station
Station is measured by where the baby's head is located in reference to the woman's ischial spines. Measurements above the ischial spines are reported as -1 to -5. Once the baby's head engages into the pelvis, or at 0 station, the baby's placement within the birth canal will be written in positive numbers. The numbers for the positive station are written as +1 to +5.
Cesarean Section
The cesarean is when a baby is surgically removed from the uterus. Most cesarean section usually takes up to an hour to complete. The surgeon normally makes two cuts in the lower abdomen before making an incision in the uterus. The baby is removed from the uterus and the umbilical cord is cut.
http://www.nlm.nih.gov/medlineplus/ency/article/002060.htm http://womenshealth.gov/pregnancy/childbirth-beyond/labor-birth.cfm