CHAPTER 18
Obstetrics
Obstetrics Overview
• Obstetrics
– Field of medicine that deals with pregnancy
(prenatal), delivery of the baby, and the first six
weeks after delivery (postpartum period)
• Pregnancy
– Nine calendar months or 10 lunar months
– Forty weeks or 280 days
– Divided into trimesters
• Three intervals of three months each
– Known as gestational period
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Pregnancy
• Fertilization or conception
– Union of a sperm and a mature ovum
• Takes place in outer third of the fallopian tube
– Zygote
• Initial name for fertilized ovum
– Embryo
• Name of product of conception from second
through 8th week of pregnancy
– Fetus
• Name of product of conception from 9th week
through duration of gestational period
3
Pregnancy
• Two major accessory structures of
pregnancy
– Amniotic sac
• Strong, thin-walled membranous sac that
envelops and protects the growing fetus
• Also known as the fetal membrane
• Outer layer of sac is called the chorion
• Inner layer of sac is called the amnion
• Amniotic fluid within sac cushions and protects
fetus during pregnancy
4
Pregnancy
• Accessory structures of pregnancy
– Placenta
• Temporary organ of pregnancy
• Provides for fetal respiration, nutrition, excretion
• Functions as an endocrine gland by producing
hormones necessary for normal pregnancy
• Human chorionic gonadotropin (HCG), estrogen,
progesterone, and human placental lactogen
(HPL)
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Pregnancy
• Accessory structures of pregnancy
– Maternal side of placenta
• Attached to wall of uterus
• Has a “beefy” red appearance
– Fetal side of placenta
• Has shiny, slightly grayish appearance
• Contains arteries and veins that intertwine to form
umbilical cord
• Umbilical cord arises from center of placenta and
attaches to umbilicus of fetus
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Physiological
Changes During Pregnancy
• Amenorrhea
– Absence of menstruation
• Menstruation stops as a result of hormonal
influence during pregnancy
• Changes in the uterus
– Small, pear-shaped organ before pregnancy
– Grows to accommodate growing fetus,
placenta, amniotic sac, and amniotic fluid
during pregnancy
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Physiological
Changes During Pregnancy
• Changes in the cervix
– Chadwick’s Sign
• Cervix and vagina take on a bluish-violet hue due
to local venous congestion
– Goodell’s Sign
• Cervix softens in consistency in preparation for
childbirth
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Physiological
Changes During Pregnancy
• Changes in the vagina
– Vagina takes on same bluish-violet hue of the
cervix during pregnancy
– Increase of glycogen in vaginal cells
• Causes increased vaginal discharge and heavy
shedding of vaginal cells
– Leukorrhea
• Thick, white vaginal discharge during pregnancy
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Physiological
Changes During Pregnancy
• Changes in breasts
– Increase in size and shape
– Nipples increase in size and become more
erect
– Areola become larger and more darkly
pigmented
• Montgomery’s tubercles become more active and
secrete substance that lubricates the nipples
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Physiological
Changes During Pregnancy
• Changes in breasts
– Colostrum is secreted
• Thin, yellowish discharge from nipples throughout
pregnancy
• Forerunner to breast milk
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Physiological
Changes During Pregnancy
• Changes in blood pressure
– May experience hypotension during second
and third trimesters (4th – 9th month)
– Weight of pregnant uterus presses against
descending aorta and inferior vena cava
• When woman is lying on her back (supine)
• May complain of faintness, lightheadedness, and
dizziness
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Physiological
Changes During Pregnancy
• Changes in urination
– First trimester
• Urinary frequency due to increasing size of uterus,
creates pressure on bladder
– Second trimester
• Uterus rises up out of the pelvis and pressure on
bladder is relieved
– Third trimester
• Frequency returns due to pressure of baby’s head
on the bladder
13
Physiological
Changes During Pregnancy
• Changes in posture
– Waddling gait
• Manner of walking in which the feet are wide apart
and the walk resembles that of a duck
• Due to softening of pelvic joints and relaxing of
pelvic ligaments
• Pregnant woman’s center of gravity is offset
14
Physiological
Changes During Pregnancy
• Changes in the skin
– Possible increased feeling of warmth and
sweating
• Due to increased activity of the sweat glands
– Possible problems with facial blemishes
• Due to increased activity of sebaceous glands
– Chloasma
• Hyperpigmentation (brown patches) seen on
forehead, cheeks, and bridge of nose
• Known as the “mask of pregnancy”
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Physiological
Changes During Pregnancy
• Changes in the skin
– Linea Nigra
• Darkened vertical midline between the fundus and
the symphysis pubis on the abdomen
– Areola
• Becomes darker as pregnancy progresses
– Stria Gravidarum
• Stretch marks on the abdomen, thighs, and breasts
that occur during pregnancy
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Physiological
Changes During Pregnancy
• Changes in weight
– Recommended weight gain during pregnancy
• Ranges from 25 to 30 pounds
– Pattern of weight gain is important
• 1st – 3rd month = 3 - 4 pounds total
• 4th – 9th month = 1 pound per week
– Critical to monitor weight gain for unexpected
increases
– Fluid retention
– Pregnancy-induced hypertension
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Signs and
Symptoms of Pregnancy
• Presumptive signs
– Expectant mother
• Suggests pregnancy but are not necessarily
positive
• Include amenorrhea, nausea and vomiting, fatigue,
urinary disturbances, and breast changes
– Quickening
• Movement of fetus felt by the mother
• Occurs around 18 – 20 weeks gestation
• Described as a faint abdominal fluttering
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Signs and
Symptoms of Pregnancy
• Probable signs
– Observable by examiner
• Much stronger indicators of pregnancy, but can be
due to other pathological conditions
• Should not be used as sole indicator of pregnancy
• Include Goodell’s sign, Chadwick’s sign, uterine
enlargement, hyperpigmentation of skin,
abdominal stria, palpation of fetal outline, positive
pregnancy tests
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Signs and
Symptoms of Pregnancy
• Probable signs
– Hegar’s sign
• Softening of the lower segment of the uterus
– Braxton Hicks contractions
• Irregular contractions of the uterus
• May occur throughout the pregnancy and are
relatively painless
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Signs and
Symptoms of Pregnancy
• Probable signs
– Ballottement
• Technique of using the examiner’s finger to tap
against the uterus, through the vagina, to cause
the fetus to “bounce” within the amniotic fluid and
feeling it rebound quickly
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Signs and
Symptoms of Pregnancy
• Positive signs
– Fetal Heartbeat
• Detected by ultrasound at approximately 10 weeks
gestation
• Detected by fetoscope at 18 to 20 weeks gestation
• Rate can vary from 120 to 180 beats per minute
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Signs and
Symptoms of Pregnancy
• Positive signs
– Identification of embryo or fetus by ultrasound
• Can be detected as early as 5 to 6 weeks with 100
percent reliability
• Provides earliest positive confirmation of a
pregnancy
– Fetal movements felt by examiner
• Palpable by physician/examiner by the second
trimester of pregnancy
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Calculation of Date of Birth
• Birth date for the baby
– Expected Date of Confinement (EDC)
– Expected Date of Delivery (EDD)
– Expected Date of Birth (EDB)
• Nagele’s rule for calculation of date
– Subtract three months from beginning of last
menstrual period (LMP)
– Add seven days to date = expected date of
delivery
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Discomforts of Pregnancy
• Temporary discomforts of pregnancy
– Backache
• Common during second and third trimester
– Edema
• Swelling of lower extremities not uncommon
– Fatigue
• Usually occurs during first trimester
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Discomforts of Pregnancy
• Temporary discomforts of pregnancy
– Heartburn
• Mainly during last few weeks of pregnancy
– Hemorrhoids
• Develop as result of increasing pressure on area
– Nausea
• Usually occurs during first trimester
– Varicose veins
• Occur as result of blood pooling in the legs
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COMPLICATIONS
OF PREGNANCY
Obstetrics
Abortion
• Pronounced
– (ah-BOR-shun)
• Defined
– Termination of a pregnancy before the fetus
has reached a viable age, that is, an age at
which the fetus could live outside of the
uterine environment
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Abruptio Placenta
• Pronounced
– (ah-BRUP-she-oh pla-SEN-tah)
• Defined
– Premature separation of a normally implanted
placenta from the uterine wall
• After the pregnancy has passed 20 weeks
gestation or during labor
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Ectopic Pregnancy
• Pronounced
– (ek-TOP-ic PREG-nan-see)
• Defined
– Abnormal implantation of a fertilized ovum
outside of the uterine cavity
– Also called a tubal pregnancy
• Approximately 90 percent of all ectopic
pregnancies occur in the fallopian tubes
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Gestational Diabetes
• Pronounced
– (jess-TAY-shun-al diy-ah-BEE-teez)
• Defined
– Disorder in which women who are not diabetic
before pregnancy develop diabetes during the
pregnancy
• Develop an inability to metabolize carbohydrates
(glucose intolerance), with resultant hyperglycemia
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Gestational Diabetes
• Risk factors
– Obesity
– Maternal age over 30 years
– History of birthing large babies
• Usually over 10 pounds
– Family history of diabetes
– Previous, unexplained stillborn birth
– Previous birth with congenital anomalies
(defects)
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HELLP Syndrome
• Pronounced
– HELLP SIN-drom
• Defined
– Serious obstetrical complication that occurs in
approximately 10 percent of pregnant women
with pre-eclampsia or eclampsia
• HELLP stands for Hemolytic anemia, Elevated
Liver enzymes, and Low Platelet count
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HELLP Syndrome
• Early diagnosis is critical
– Any woman who presents with malaise or a
viral-type illness in third trimester of
pregnancy should be evaluated for possibility
of HELLP Syndrome
• Laboratory diagnosis necessary to confirm
HELLP syndrome
– Complete blood cell count
– Liver function tests
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Hydatidiform Mole
• Pronounced
– (high-dah-TID-ih-form mohl)
• Defined
– Abnormal condition that begins as a
pregnancy and deviates from normal
development very early
• Diseased ovum deteriorates (not producing a
fetus)
• Chorionic villi of placenta changes to a mass of
cysts resembling a bunch of grapes
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Hydatidiform Mole
• Hydatidiform mole
– Molar pregnancy
– Hydatid mole
– Growth of this mass progresses much more
rapidly than uterine growth with a normal
pregnancy
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Hyperemesis Gravidarum
• Pronounced
– (high-per-EM-eh-sis grav-ih-DAR-um)
• Defined
– Abnormal condition of pregnancy
characterized by severe vomiting that
results in maternal dehydration and weight
loss
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Incompetent Cervix
• Pronounced
– (in-COMP-eh-tent SER-viks)
• Defined
– Condition in which cervical os dilates before
the fetus reaches term, without labor or
uterine contractions
• Usually occurs during second trimester of
pregnancy
• Results in spontaneous abortion of fetus
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Placenta Previa
• Pronounced
– (plah-SEN-tah PRE-vee-ah)
• Defined
– Condition of pregnancy in which the placenta
is implanted in the lower part of the uterus
• Precedes the fetus during the birthing process
39
Pregnancy-Induced
Hypertension (PID)
• Pronounced
– (PREG-nan-see induced high-per-TENshun)
• Defined
– Development of hypertension during
pregnancy, in women who had normal blood
pressure readings prior to pregnancy
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Pregnancy-Induced
Hypertension (PID)
• Three categories of PID
– Gestational hypertension
• Develops after 20 weeks gestation with no signs of
edema or proteinuria
– Pre-eclampsia
• Develops after 20 weeks gestation with proteinuria
or edema
– Eclampsia
• Most severe form of hypertension during
pregnancy
• Evidenced by presence of seizures
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Rh Incompatibility
• Pronounced
– (Rh Incompatibility)
• Defined
– Incompatibility between and Rh negative
mother’s blood with her Rh positive baby’s
blood
• Causes mother’s body to develop antibodies that
will destroy the Rh positive blood
42
SIGNS AND
SYMPTOMS OF LABOR
Obstetrics
Signs and Symptoms of Labor
• Bloody show
– Vaginal discharge that is a mixture of thick
mucus and pink or dark brown blood
• Occurs as a result of the softening, dilation, and
thinning (effacement) of the cervix in preparation
for childbirth
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Signs and Symptoms of Labor
• Braxton Hicks contractions
– Mild, irregular contractions that occur
throughout pregnancy
• Increased vaginal discharge
– Clear, nonirritating vaginal secretions
– Occurs as result of congestion of vaginal
mucosa
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Signs and Symptoms of Labor
• Lightening
– Settling of the fetal head into the pelvis
• Occurs a few weeks prior to the onset of labor
• Rupture of the amniotic sac
– Rupture of fetal membranes, releasing
amniotic fluid inside
• May result in a sudden gush of amniotic fluid
• Women may say their “water broke”
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Signs and Symptoms of Labor
• Sudden burst of energy
– Occurs in some women shortly before onset
of labor
– May have energy to do major housecleaning
duties
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False Labor
versus True Labor
Contractions (False)
Contractions (True)
Irregular
Regular
Not too frequent
More frequent
Shorter duration
Longer duration
Not too intense
More intense
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False Labor
versus True Labor
Discomfort (False)
Discomfort (True)
Felt in abdomen
Felt in lower back
Felt in groin area
Radiates to lower
abdomen
---
Feels like menstrual
cramps
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False Labor
versus True Labor
Walking (False)
Walking (True)
May relieve or decrease May strengthen
contractions
contractions
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False Labor
versus True Labor
Effacement/Dilatation
(False)
Effacement/Dilatation
(True)
Dilatation and
effacement of cervix
does not change
Cervix progressively
effaces (thins) and
dilates (enlarges)
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DIAGNOSTIC
TECHNIQUES, TREATMENTS
AND PROCEDURES
Obstetrics
Diagnostic Techniques,
Treatments, and Procedures
• AFP screening
– Serum screening test for birth defects such as
spina bifida, Down syndrome, and Trisomy 18
• Test is offered to pregnant women between 15 and
21 weeks gestation
53
Diagnostic Techniques,
Treatments, and Procedures
• Amniocentesis
– Surgical puncture of the amniotic sac for the
purpose of removing amniotic fluid
• Cesarean section
– Surgical procedure in which the abdomen and
uterus are incised and a baby is delivered
transabdominally
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Diagnostic Techniques,
Treatments, and Procedures
• Contraction stress test
– Stress test used to evaluate ability of fetus to
tolerate stress of labor and delivery
• Also known as oxytocin challenge test
• Fetal monitoring
– Use of an electronic device to monitor fetal
heart rate and maternal uterine contractions
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Diagnostic Techniques,
Treatments, and Procedures
• Nipple stimulation test
– Noninvasive technique that produces same
results as contraction stress test
• Pregnant woman stimulates the nipples of her
breasts by rubbing them between her fingers
• Causes natural release of oxytocin that causes
contractions of uterus
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Diagnostic Techniques,
Treatments, and Procedures
• Obstetrical ultrasound
– Noninvasive procedure that uses highfrequency sound waves to examine internal
structures and contents of the uterus
– Ultrasonography
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Diagnostic Techniques,
Treatments, and Procedures
• Pelvic ultrasound
– Noninvasive procedure that uses highfrequency sound waves to examine the
abdomen and pelvis
• Pelvimetry
– Process of measuring the female pelvis,
manually or by x-ray to determine its
adequacy for childbearing
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Diagnostic
Techniques and Procedures
• Pregnancy testing
– Tests performed on maternal urine and/or
blood to determine presence of hormone
HCG (human chorionic gonadotropin)
• HCG is detected shortly after first missed
menstrual period
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