Childbirth
Childbirth
(also
called
labour, birth,
partus or parturition) is the culmination of
a human pregnancy or gestation period with
birth of one or more newborn infants from a
woman’s uterus. The process of normal hu-
man childbirth is categorized in three stages
of labour: the shortening and dilation of the
cervix, descent and birth of the infant, and
birth of the placenta.[1]. In some cases, child-
birth is achieved through caesarean section,
the removal of the neonate through a surgic-
al
incision in the abdomen, rather than
through vaginal birth.
The mechanics of vaginal
birth
Because humans are bipedal with an erect
stance and have, in relation to the size of the
pelvis, the biggest head and shoulders of any
species, human fetuses are adapted to make
birth possible.
The erect posture causes the weight of the
abdominal contents to thrust on the pelvic
floor, a complex structure which must not
only support this weight but allow three
channels to pass through it: the urethra, the
vagina and the rectum. The relatively large
head and shoulders require a specific se-
quence of manoeuvres to occur for the bony
head and shoulders to pass through the bony
ring of the pelvis. If these manoeuvres fail,
the progress of
labour
is arrested. All
changes in the soft tissues of the cervix and
the birth canal are entirely dependent on the
successful
completion
of
these
six
maneuvers:
1. of the fetal head in the transverse
position. The baby is looking across the
pelvis at one or other of the mother’s hips.
2. of the fetal head
3. . The fetal head rotates 90 degrees to the
occipito-anterior position so that the
baby’s face is towards the mother’s
rectum.
4. . The fetal head passes out of the birth
canal. Its head is tilted backwards so that
its forehead leads the way through the
vagina.
5. . The fetal head turns through 45 degrees
to restore its normal relationship with the
shoulders, which are still at an angle.
6. . The shoulders repeat the corkscrew
movements of the head, which can be seen
in the final movements of th