CARE OF MOTHER 3-10 Flashcards
3-10
Although a number of theories have been proposed
to explain why labor begins, it is believed that labor is
influenced by a combination of factors originating
from the mother and the fetus (____).
Katz, 2003
Possible Causes of the Onset of Labor
Maternal Factor Theories
Pressure on the cervix stimulates nerve plexus,
causing release of oxytocin by maternal posterior
pituitary gland. This is known as
Ferguson reflex
Possible Causes of the Onset of Labor
Maternal Factor Theories
Uterine muscles stretch, causing release of
prostaglandin.
Ferguson reflex.
Oxytocin and
prostaglandin work together to inhibit calcium
binding in muscles cells, raising intracellular calcium
and thus activating contractions.
Estrogen/progesterone ratio shift
Possible Causes of the Onset of Labor
Fetal Factor Theories
Placental aging and deterioration triggers initiation of
contractions
Fetal cortisol, produced by the fetal adrenal glands,
rises and acts on the placenta to reduce
progesterone formation and increase prostaglandin
Prostaglandin produced by fetal membrane s
(amnion and chorion) and the decidua stimulates
contractions. When arachidonic acid stored in fetal
membranes is released at term, it is converted to
prostaglandin
Factors Affecting Labor
Passageway
Type of pelvis (e.g. gynecoid, android, anthropoid,
or platypelloid)
Structure of pelvis (e.g. true versus false pelvis)
Pelvic inlet diameters
Pelvic outlet diameters
Ability of the uterine segment to distend, the cervix
to dilate, and the vaginal canal and introitus to
distend
Factors Affecting Labor
Passenger
Size of the fetal head and capability of the head
to mold to the passageway
Fetal presentation
Fetal attitude
Fetal position
Factors Affecting Labor
Power
frequency, duration, and strength (intensity)
of uterine contractions to cause complete cervical
effacement and dilation
Factors Affecting Labor
Placental factors
site of placental insertion.
Factors Affecting Labor
Psyche
refers to the client’s psychological state;
available support systems, preparation for child birth,
experiences , and coping strategies.
Signs and symptoms of impending labor
(Premonitory
Signs)
are irregular, intermittent
contractions that have occurred throughout the
pregnancy, become uncomfortable, and produce a
drawing pain in the abdomen and groin
Braxton Hicks contractions
Signs and symptoms of impending labor (Premonitory
Signs)
Lightening
Braxton Hicks
Cervical changes include softening , “ripening” and
effacement of the cervix
Rupture of amniotic membranes
Burst of energy or increased tension and fatigue may
occur right before the onset of labor
Cervical changes include
softening , “ripening” and
effacement of the cervix that will cause expulsion of
the mucous plug (bloody show).
Characteristics of True Labor
Contractions occur at regular intervals
Contractions e back and sweep around to the abdomen , increase in intensity and duration , shortened intervals.
Walking intensifies contractions.
Bloody show”
Cervix becomes effaced and dilated
Sedation does not stop contractions
Characteristics of False Labor
Contractions occur at irregular intervals.
Contractions are located chiefly in the abdomen, the
intensity remains the same or is variable, and the
intervals remain long.
Walking does not intensify contractions and often
gives relief.
Bloody show usually not is not present. If present, it is
usually brownish rather than bright red and may be
due to a recent pelvic examination or intercourse.
There are no cervical changes.
Sedation tetends to decrease the number of
contractions.
primiparas
(longer)
multiparas
shorter),
“ occurs when the newborn’s head or
presenting part appears at the vaginal opening.
“Crowning“
(surgical incision in perineum)
Episiotomy