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What is the function of the cervix?

The cervix is the lower part of the uterus that projects into the vagina. Made up of mostly fibrous tissue and muscle, the cervix is circular in shape. During pregnancy, the cervix lengthens, serving as a barrier. When labor begins, the cervix begins to shorten, dilating to an opening of about 10 centimeters (about four inches) to allow the fetus to pass through. The cervix also thins and merges with the uterus (effacement) during the first stage of labor.

What is labor?

Labor is a series of continuous, progressive contractions of the uterus which help the cervix to open (dilate) and to thin (efface), allowing the fetus to move through the birth canal. Labor usually starts two weeks before or after the estimated date of delivery. However, no one knows exactly what triggers the onset of labor.

What are the signs of labor?

Signs of labor vary from woman to woman, as each woman experiences labor differently. Some common signs of labor may include:

If a woman feels unsure if labor is beginning, she should always call her physician.

What are the different stages of labor?

Each labor is different. However, labor typically is divided into three stages:

First Stage The first phase of the first stage of labor is called the latent phase, when contractions are becoming more frequent (usually 5 to 20 minutes apart) and somewhat stronger. However, discomfort is minimal. The cervix dilates (opens approximately three or four centimeters) and effaces (thins out). Some women may not recognize that they are labor if their contractions are mild and irregular.

The latent phase is usually the longest and least intense phase of labor. The mother-to-be is usually admitted to the hospital during this phase. Pelvic exams are performed to determine the dilatation of the cervix.

The second phase of the first stage (active phase) is signaled by the dilatation of the cervix from 4 to 7 centimeters. Contractions become longer, more severe, and more frequent (usually 3 to 4 minutes apart).

The third phase is called transition and is the last phase. During transition, the cervix dilates from 8 to 10 centimeters. Contractions are usually very strong, lasting 60 to 90 seconds and occurring every few minutes. Most women feel the urge to push during this phase.

In most cases, the active and transition phases are shorter than the latent phase.

Second Stage The second stage of labor begins when the cervix is completely opened and ends with the delivery of the baby. The second stage is often referred to as the "pushing" stage. During the second stage, the woman becomes actively involved by pushing the baby through the birth canal to the outside world. When the baby's head is visible at the opening of the vagina, it is called "crowning." The second stage is shorter than the first stage, and may take between 30 minutes to two hours for a woman's first pregnancy.
Third Stage After the baby is delivered, the new mother enters the third and final stage of labor - delivery of the placenta (the organ that has nourished the baby inside of the uterus). This stage usually lasts just a few minutes and involves the passage of the placenta out of the uterus and through the vagina.
Illustration demonstrating the three stages of labor
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Each labor experience is different and the amount of time in each stage will vary. However, labor in a first pregnancy usually lasts about 12 to 14 hours. Labor is generally shorter for subsequent pregnancies.

Induction of labor:

In some cases, labor has to be "induced," which is a process of stimulating labor to begin. The reasons for induction vary. Some common reasons for induction include the following:

Some common techniques of induction include the following:

Relaxation techniques to use during labor are often taught in childbirth classes. Especially in natural childbirth, which does not use medications to relieve pain, relaxation and breathing techniques can help a woman feel more in control and able to manage her pain.

Care at the hospital during labor:

When a woman arrives at the hospital in labor, the medical staff may perform a physical examination of the abdomen to determine the size and position of the fetus, and an examination of the cervix. In addition, the medical staff may check the following:

Intravenous fluids are sometimes given during labor to prevent dehydration. The intravenous line, a thin plastic tube inserted into a vein (usually in the patient's forearm), can also be used to administer medications. Intravenous fluids are also needed when a woman has epidural anesthesia.

The fetus, too, is carefully monitored during labor. A monitor placed over the mother's abdomen will keep track of the fetal heart rate.

What are pain management options during labor?

A woman has many options for managing the discomforts that occur during labor and the birth of her baby. Generally, mothers and their physicians want to use the safest and most effective method of pain relief for both mother and baby. The choice will be determined by:

There are three main types of pain management for labor and birth:

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Online Resources of Pregnancy & Childbirth

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