Encyclopedia of Health and Medicine

childbirth 261
Outlook and Lifestyle Modifications
While the incision is healing the woman needs
substantial help carrying and lifting the infant as
well as with daily activities. After healing is complete
the woman may and should return to full
activities, including SEXUAL INTERCOURSE as she
desires. Cesarean section does not affect the ability
to breastfeed for as long as the woman desires or
the potential for becoming pregnant again. Vaginal
delivery with subsequent pregnancies (VBAC, or
vaginal birth after cesarean) is possible for about
two thirds of women who had transverse incisions
on the uterus. Most obstetricians consider a vertical
incision on the uterus too risky for VBAC
because the stress of labor may cause the incisional
SCAR on the uterus to rupture.
For further discussion of cesarean section,
please see the overview section “The Reproductive
System.”
See also APGAR SCORE; POSTOPERATIVE PROCEDURES;
PREOPERATIVE PROCEDURES; SURGERY BENEFIT AND RISK
ASSESSMENT.
childbirth The passage of the FETUS from the
UTERUS to independent life outside the woman’s
body as PREGNANCY culminates. The physiologic
processes that establish this passage are labor and
delivery (vaginal birth); childbirth may also occur
as a surgical procedure (CESAREAN SECTION). Labor
refers to the progressively intense contractions of
the uterus that dilate and efface (stretch and thin)
the CERVIX, then push the fetus into and through
the VAGINA (birth canal).
Though labor and delivery occur in predictable
and sequential stages, their timing varies widely.
Early labor may last a few to 36 hours. Active
labor generally lasts 2 to 8 hours. Delivery, the
passage of the baby through the birth canal, may
take 15 minutes to 2 hours. A woman’s first delivery
typically takes longer than subsequent deliveries.
Though childbirth is a natural process, in the
United States most childbirth takes place in hospitals
or birthing centers with medical professionals
(doctors, nurses, midwives) providing care and
assistance.
Stage 1: Labor
Labor is the work of the uterus and abdominal
muscles to ready the woman’s body for birth and
ultimately push the infant out. For more than 40
weeks the body’s focus has been on maintaining
the pregnancy within it. As the time for birth
approaches, hormonal signals initiate the
sequence of events that will make delivery possible.
Researchers do not know what starts the hormonal
cascade that ultimately results in childbirth,
though these changes begin some time before
actual labor starts.
Though the most intense experience of labor is
in the hours that lead to delivery, the preparations
actually begin several weeks before birth. One of
the earliest signs of impending birth is the dropping
of the presenting part of the fetus, usually
the head, into the start of the cervix. Called
engagement or lightening, this movement indicates
the cervix is beginning to efface. It also signals
changes that are occurring within the fetus to
prepare it for life outside the womb, notably
expansion of the LUNGS.
As the cervix continues to efface and begins to
dilate the plug of mucus that formed in the cervical
canal comes loose and slides out, which the woman
may notice as a brownish discharge (sometimes
called bloody show). This may occur a week or
longer before birth. The characteristic experience of
labor begins with sensations of tightening and
relaxing in the lower abdomen, somewhat similar
in experience to menstrual cramps. Many women
feel these sensations in the lower back as well. The
woman may feel restless and want to walk around;
walking helps strengthen and coordinate contractions
as they progress. Labor becomes more intense
and focused when the membranes rupture, often
called water breaking.
There are many ways women cope with the
discomfort of labor, which intensifies as the labor
progresses. Methods such as relaxation BREATHING,
massage, acupuncture, and visualization often
help a woman feel calm and centered. Some
women become intensely active in the early stages
of labor, cleaning house and otherwise “nesting.”
Doctors believe this behavior harkens to primal
instincts of preparedness. In early labor contractions
may be 10 to 15 minutes apart and last
about 30 seconds and may become less intense
with certain positions or activities. As early labor
progresses to active labor, contractions are about 5
minutes apart and last for 45 to 60 seconds.