Labor

Labor is the process of regular uterine contractions and cervical change that leads to childbirth. It culminates in delivery of the baby and placenta.

Uterine contraction: A rhythmic tightening of uterine muscle that can contribute to cervical change and move the fetus downward. Repeated contractions generate the forces that drive labor forward.
First stage of labor: The period from the onset of labor to complete cervical dilation. This stage encompasses cervical effacement and dilation.
Labor induction: The intentional initiation of labor before it begins spontaneously. Induction starts the process when birth is recommended before spontaneous labor.
Preterm labor: Labor that begins before 37 completed weeks of pregnancy. Its timing makes labor a preterm birth risk rather than a term process.
Cervical dilation: The opening of the cervix, measured in centimeters, as it widens during labor. Progress is commonly assessed by how far the cervix has opened.
Second stage of labor: The period from complete cervical dilation to birth of the baby. This is the pushing and birth phase after the cervix is fully open.
Labor augmentation: Interventions used to strengthen or increase contractions after labor has begun. Augmentation addresses labor that has started but is progressing inadequately.
Precipitous labor: Labor and birth completed in less than three hours from the onset of regular contractions. It is an unusually rapid course with distinct clinical concerns.
Cervical effacement: Thinning and shortening of the cervix as it prepares for birth. Effacement is a key part of the cervical change that accompanies dilation.
Third stage of labor: The period from birth of the baby to delivery of the placenta. Labor is not complete until the placenta is delivered.

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