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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:
- bloody show
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 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 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.
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| 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. |
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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:
- 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
- diagnosis of poor growth of the fetus
Some common techniques of induction include the following:
- 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.
- rupturing (artificially) the amniotic
sac membranes (bag of waters).
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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.
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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:
- blood pressure
- weight
- temperature
- frequency and intensity of contractions
- fetal heart rate
- urine and blood samples
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:
- patient and family preference.
- the health of the patient.
- the health of fetus.
- the physician's recommendation.
There are three main types of pain management
for labor and birth:
- non-medicated measures - provide comfort
and relieve stress, sometimes called natural childbirth. Many
women learn special techniques to help them feel more comfortable
and in control during labor and birth. Some of these techniques
include:
- relaxation - techniques such as progressive
relaxation, in which various muscle groups are relaxed in
series, can help a woman detect tension and be better able
to release that tension
- touch - this may include massage or
light stroking to relieve tension. A jetted bath or a shower
during labor may also be effective ways to relieve pain or
tension. Ask your physician before taking a tub bath in labor.
- heat or cold therapy - used to help
relax tensed or painful areas, such as a warmed towel or a
cold pack
- imagery - technique of using the mind
to form mental pictures that help create relaxed feelings
- meditation or focused thinking - focusing
on an object or task, such as breathing helps direct the mind
away from the discomforts
- breathing - techniques using different
patterns and types of breathing to help direct the mind away
from the discomforts
- positioning and movement - many women
find changing positions and moving around during labor helps
relieve discomfort and may even speed labor along. Rocking
in a rocking chair, sitting in the "Tailor sit"
position, sitting on a special "birthing ball,"
walking, and swaying may be helpful. Your labor nurse or physician
can help you find comfortable positions that are also safe
for you and your baby.
- analgesics - medications to relieve pain
such as meperidine. The smallest dose possible is given because
of the potential adverse effects of these drugs on the fetus.
These drugs easily cross the placenta to the fetus and may take
a long time to clear from the baby's system even after birth.
Many analgesics can cause respiratory depression (slowing of
the breathing center in the brain) in mothers and babies if
given in large amounts or in repeated doses.
- anesthesia - medications that cause loss
of sensation include pudendal block, epidural anesthesia and
analgesia, spinal anesthesia and analgesia, and general anesthesia.
- local block - anesthesia injected in
the perineal area - the area between the vagina and rectum-
to numb the area for repair of a tear or episiotomy after
delivery
- 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. It is
used for vaginal deliveries.
- epidural anesthesia (Also called an
epidural block.) - this anesthesia involves infusing numbing
medications through a thin catheter that has been inserted
into the space that surrounds the spinal cord in the lower
back, causing loss of sensation of the lower body. Infusions
of medications may be increased or stopped as needed.
This type of anesthesia is used during labor and for vaginal
and cesarean deliveries. The most common complication of epidural
anesthesia is low blood pressure in the mother. Because of
this, most woman need to have an intravenous infusion of fluids
before epidural anesthesia is given. The anesthesiologist
will discuss the risks, benefits, and alternatives to the
various methods of pain relief with the patient.
- epidural analgesia - this is sometimes
called a "walking" epidural because the medication
infused through the epidural is an analgesic, which relieves
pain but does not numb the body and allows movement. Combinations
of medications may be used in the epidural - part analgesic,
part anesthetic. The most common complication of epidural
analgesia is low blood pressure in the mother. This type of
anesthesia is used during labor and for vaginal deliveries.
A risk of epidural analgesia is a postpartum headache. It
may develop if the epidural needle enters the spinal canal,
rather than staying in the space around the canal. Epidural
analgesia may be used for pain relief in labor and for vaginal
deliveries.
- spinal anesthesia - this type of anesthesia
involves injecting a single dose of the anesthetic agent directly
into the spinal cord canal. Spinal anesthesia acts very quickly
and causes complete loss of sensation and loss of movement
of the lower body. This type of anesthesia is often used for
cesarean deliveries.
- spinal analgesia - this involves injecting
a analgesic medication into the spinal cord canal to provide
pain relief without numbing. Spinal analgesia may be used
in combination with epidural anesthesia or analgesia. This
may be used during labor for pain relief.
- 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.
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