| 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. |
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 person to person, as each woman experiences labor differently.
Some common signs of labor may include:
A small amount of mucus, slightly mixed with blood, may be expelled from the vagina
indicating a woman is in labor.
contractions
Contractions (uterine muscle spasms) occurring at intervals of less than ten minutes are
usually an indication that labor has begun; contractions may become more frequent and
severe as labor progresses.
rupture of amniotic sac membranes (bag of waters)
Labor sometimes begins with amniotic fluid gushing or leaking from the vagina. Women who
experience a rupture of the amniotic sac membranes should contact their physician
immediately. The majority of women with ruptured membranes go into labor within 24 hours.
If labor still has not begun after 24 hours, a woman may be hospitalized for labor to be
induced. This step is often taken to prevent infections and delivery complications.
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 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 at this point. Pelvic exams
are performed to determine the dilatation of the cervix.
The second phase of the first stage (active phase) is signaled by
the dilation of the cervix from 4 to 10 centimeters (approximately 4 inches). Contractions
become longer, more severe, and more frequent (usually 3 to 4 minutes apart) and the woman
begins to feel the urge to push.
In most cases, the active phase is shorter than the latent phase,
usually averaging about 5 hours in a woman’s first pregnancy. |
| 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 generally
takes between 30 – 60 minutes in 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. |
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 mother and/or fetus are at risk
- the pregnancy has continued too far past the due date
- the mother has preeclampsia, eclampsia, or chronic hypertension
- Rh incompatibility between the mother and fetus
- diagnosis of growth retardation of the fetus
- labor has not progressed of is stalled, particularly if the amniotic sac has already
ruptured
Some common techniques of induction include:
- rupturing (artificially) the amniotic sac membranes (bag of waters).
- inserting vaginal suppositories that contain prostaglandin hormone to stimulate
contractions.
- administering an intravenous infusion of oxytocin (a hormone produced by the pituitary
gland that stimulates contractions) or similar drug.
| 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 control
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 vagina, only if the amniotic sac is still intact. In addition, the
medical staff will check the following:
- blood pressure
- weight
- temperature
- frequency and intensity of contractions
- fetal heart rate
- urine and blood samples
Intravenous fluids are generally 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.
The fetus, too, is carefully monitored during labor. A monitor placed over the
mother’s abdomen will keep track of the fetal heart rate, which can indicate
distress.
Pain management options during labor:
There are many options of pain management during labor and delivery. A woman may choose
natural childbirth (involves rhythmic breathing and relaxation techniques to relieve
pain), anesthesia (administering drugs that cause loss of sensation), or analgesics (drugs
that relieve pain). The choice will be determined by:
- the mother-to-be's preference
- the health of the mother-to-be
- the health of fetus
- the physician's preference
Some of the more common types of pain relief for labor and delivery include:
analgesics (i.e., meperidine or morphine) - given to relieve pain; the smallest
dose possible is given of these drugs because of the potential adverse effects on the
fetus.
pudendal block - a type of local anesthesia that is injected into the vaginal
area (affecting the pudendal nerve) causing complete numbness in the vaginal area without
affecting the contractions of the uterus. The woman can remain active in pushing the baby
through the birth canal.
lumbar epidural injection (Also called an epidural block.) - this injection
involves continually infusing drugs through a thin catheter that has been inserted into
the space that surrounds the spinal cord in the lower back, causing numbness of the lower
body. Infusions of medications may be increased or stopped as needed. This type of
anesthesia is used in both vaginal and cesarean deliveries.
spinal anesthesia - this injection involves injecting a single dose of the
anesthetic agent directly into the spinal cord canal, causing numbness of the lower body.
This type of anesthesia may be used in vaginal or cesarean deliveries. However, it may
affect the ability of the woman to push effectively.
general anesthesia - this type of pain relief involves administering an
anesthetic agent that causes the woman to go to sleep. This type of anesthesia may be used
in emergency cesarean deliveries.
Click here to view the
Online Resources page of this Web. |
