Physiology of Labor: A Basic Overview

Physiology of Labor: A Basic Overview

Labor is the process by which a woman’s body prepares to give birth. It is divided into three main stages: the cervical dilation stage, the pushing stage, and the placental delivery stage.

Cervical Dilation Stage (Stage 1):

• Uterine Contractions: This is the main sign of labor. Contractions usually start in one horn of the uterus and spread throughout the entire uterus. The frequency and intensity of contractions increase over time.

• Cervical Effacement and Dilation: The cervix gradually thins and widens to allow the baby to pass through.

• Mucus Plug: This is a layer of mucus that protects the cervix, and it will come out when the cervix begins to dilate.

• Amniotic Fluid (Water Breaking): The amniotic fluid may rupture before or during labor.

Pushing Stage (Stage 2):

• Pushing: When the cervix is fully dilated, the mother will feel the urge to push to deliver the baby.

• Delivery: The baby will be delivered after a series of pushing contractions.

Placental Delivery Stage (Stage 3):

• Placental Separation: After the baby is born, the placenta will separate from the wall of the uterus.

• Placental Delivery: The placenta will be delivered.

Things to Note:

• Minimum Gestational Age for Labor: 22 weeks.

• Average Labor Time: 16 – 24 hours.

• Monitoring Contractions: Monitor contractions for at least 10 minutes to assess their frequency, intensity, and regularity.

• Fetal Heart Rate: Normal fetal heart rate during labor is 120-160 beats per minute.

• Uterine Blood Flow: Uterine blood flow decreases by about 30% during each contraction but returns to normal after the contraction ends.

• Monitoring Labor with the Fetal Heart Monitor (CTG): The CTG helps monitor the fetal heart rate, uterine contractions, and the effects of contractions on the fetal heart rate.

Note: This is only a general overview of labor physiology. Consult reliable sources for further information on this process.