Uterine contractions

Uterine contractions are the tightening and shortening of the myometrium (the muscle layer) of the uterus during labor, leading to the dilation of the cervix and eventual birth of the baby.

Physiology

Uterine contractions are initiated by the hormone oxytocin, which is released by the pituitary gland. The contractions are rhythmic, meaning they occur at regular intervals, and they increase in frequency and intensity as labor progresses.

Types of contractions

There are three types of uterine contractions:

• Braxton Hicks contractions: These are often referred to as "false labor" because they do not lead to birth. They are usually painless and irregular, and they can occur at any time during pregnancy.

• Labor contractions: These are the contractions that lead to birth. They are regular, painful, and increase in frequency and intensity as labor progresses.

• Afterpains: These are contractions that occur after birth. They are caused by the uterus shrinking back to its pre-pregnancy size.

Measurement

The strength of uterine contractions can be measured using a tocodynamometer, which is a type of pressure sensor. The frequency and duration of contractions can also be monitored using this device.

See also

• Childbirth
• Pregnancy
• Oxytocin
• Myometrium

Uterine contractions Resources
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