Chapter 7: Physiologic Adaptations To Pregnancy Flashcards
Anatomical and physiologic changes of the uterus during pregnancy include
- Uterine growth
- Contractility
- Uterine Blood Flow
By 12 weeks gestation, the fundus of the uterus can be found where?
Can be palpate above the symphysis pubis.
At 16 weeks, the fundus of the uterus extends where?
Reaches midway between the symphysis pubis and the umbilicus.
At 20 weeks, the fundus of the uterus can be found where?
At the umbilicus.
The fundus of the uterus reaches its highest level where and when?
At 36 weeks gestation, it reaches the highest level at the xiphoid process.
Lightening
- When the fetal head descends into the pelvic cavity and the uterus sinks to a lower level by 40 weeks gestation.
- This descent of the fetal head reduces pressure on the diaphragm and makes reaching easier.
How does contractions of the uterus change during pregnancy?
-Braxton Hicks Contractions occur
How does blood flow to the uterus change during pregnancy?
As the uterus enlarges, an increase in the size and number of blood vessels expands blood flow dramatically
Anatomical and physiologic changes of the cervix during pregnancy include
- Water content and vascularity increases
- Hyperemia
- Chadwick Sign
- Goodell Sign
- Mucus plug
What causes hyperemia (congestion with blood) of the cervix during pregnancy?
Increasing levels of estrogen.
Leads to Chadwick sign.
Chadwick sign
Bluish purple discoloration of the cervix, vagina, and labia during pregnancy as a result of increased vascular congestion.
Earliest sign of pregnancy.
Goodell Sign
Softening of the cervix during pregnancy.
Mucus Plug
Plug in the cervical canal that blocks the ascent of bacteria from the vagina into the uterus during pregnancy to help protect the fetus and uterine membranes from infection.
Anatomical and physiologic changes of the respiratory system during pregnancy include
- Oxygen consumption
- Hormonal factors such as progesterone and estrogen
- Physical effects of the enlarging uterus
How does oxygen consumption change during pregnancy?
-Rises by 20%
How does progesterone cause respiratory changes during pregnancy?
- Along with prostaglandins, help decrease airway resistance by up to 50% by relaxing the smooth muscle in the respiratory tract.
- Increase sensitivity of the respiratory center in the medulla to CO2, thus stimulating the increase in minute ventilation.
How does estrogen cause respiratory changes during pregnancy?
- Causes increased vascularity of mucous membranes of the upper respiratory tract
- This leads to edema and hyperemia developed within the nose, pharynx, larynx and trachea.
- This congestion may cause nasal and sinus stuffiness, nosebleed and deepening of the voice.
- May also cause fullness in the ears.
How does the physical effects of the enlarging uterus cause respiratory changes during pregnancy?
- Complaints of SOB (enlarging uterus lifts the diaphragm)
- Increasing size of the uterus interferes with blood return from lower extremities.
- Ribs flare, the substernal angle widens and transverse diameter of the chest expands.
- Breathing become thoracic rather than abdominal -> dyspnea.
Anatomical and physiologic changes of the cardiovascular system during pregnancy include changes in
- Heart size and position
- Heart sounds
- Blood volume
- Plasma volume
- Red blood cell volume
- Cardiac output
- Blood pressure
- Systemic vascular resistance
- Supine hypotension
- Blood flow
- Blood components
Braxton Hicks
Irregular, painless contractions occur throughout pregnancy, although many expectant mothers do not notice them until the third trimester.
Aka false labor.
Hegar sign
Softening of the lower uterine segment that allows it to be easily compressed at 6 to 8 weeks of pregnancy.
Ballottement
Movement after a sudden tap on the cervix during a vaginal examination that causes the fetus to rise in the amniotic fluid and then rebound to its original position.
Gravida
Refers to a woman who is or has been pregnant, regardless of the length of pregnancy. # of pregnancies.
Para
Refers to the number of pregnancies that have ended at 20+ weeks, regardless of whether the infant was born alive or stillborn.
TPAL
T: term pregnancies delivered (37+ weeks)
P: preterm pregnancies delivered(20 weeks to 30 weeks + 6 days)
A: Abortion
L: Number of living children
For multifetal pregnancies, what should you use for gravida, para and TPAL?
Use # of infants not pregnancies!!
Nagele’s Rule
- Used to establish the estimated date of delivery (EDD).
- This method involves subtracting 3 months from the date the last normal menstrual period began, adding 7 days and then correcting the year.
EDB or EDC
..
Ectopic Pregnancies are considered
Abortions!!
Fetal Assessment include
- Fungal Height
- Fetal Heart Rate
- Fetal Activity
- Heart Tones
- Ultrasound Screening
Fungal Height Measurement
Method of evaluating fetal growth and confirming gestational age.
Fungal Height Measurement Procedure
- Bladder must be empty to avoid elevation of the uterus.
- Woman lies on back with knees slightly flexed.
- Top of fundus is palpated and a tape measure is stretched from the top of symphysis pubis, over the abdominal curve, to the top of the fundus.
Fetal Heart Rate Location
Location of the fetal sounds provides information that helps determine the position in which the fetus is entering the pelvis.
Fetal Activity
- Aka quickening.
- First noticed by expectant mother at 16 to 20 weeks of gestation and gradually increase in frequency and length.
- Is a reassuring sign that indicates a physically healthy fetus.
Fundal Height from 16 to 38 weeks
Is measured in cm, is equal to the gestation age of the fetus in weeks, within 3 cm.
FHR may be heard
*Starting approx. at 10-12 weeks gestation with
-a Doppler transducer in early pregnancy
OR
-a fetoscope in later pregnancy
What are common signs and symptoms of pregnancy?
- N/V
- Heartburn
- Constipation
- Fatigue
- Ptyalism
- Urinary frequency, urgency, incontinence
- UTI
- Nocturia
- Gingivitis and bleeding gums
What are nursing interventions for N/V during pregnancy?
- Small snacks throughout the day (n/v can be brought on by an empty stomach)
- Suck on hard candy
- Drink fluids frequently but separate from meals
- Carbohydrates are tolerated the best
- Avoid spicy, greasy foods, heavy meats
- Gingerale
- Take prenatal vitamins at night (can contribute to the sickness if given in the morning)
- Medications
How does heart size change during pregnancy?
Myocardium enlarges slightly d/t increased workload during pregnancy.
How does the position of the heart change during pregnancy?
Is pushed upward and to the left as the uterus elevates the diaphragm during the third trimester.
How does heart sounds change during pregnancy?
- May have splitting of the first heart sound
- May have a systolic murmur, best heard at the left sternal border.
- May have a third heart sound because of rapid filling during diastole.
How does blood volume change during pregnancy?
-Total blood volume increase; Begins by 6 weeks.
Increases susceptibility to have DVT.
How does plasma volume change during pregnancy?
- Plasma volume increases from 6-8 weeks until 32 weeks gestation (by 40-60%)
- Dilution may counter the tendency to form clots
- Hemodilution may increase placental perfusion.
Increased plasma volume is needed for three reasons
- To transport nutrients and oxygen to the placenta
- To meet the demands of the expanded maternal tissue in the uterus and breasts
- Provide a reserve to protect pregnant women from adverse effects of blood loss that occurs during birth
Physiologic Anemia
Reflects dilution of RBCs in the expanded plasma volume rather than an actual decline in the number of RBCs and does not indicate true anemia (this is normal)
Iron deficiency anemia (true anemia) occurs when
The hemoglobin level is less than 11 g/dL in the first and third trimesters or less than 10.5 g/dL in the second trimester.
How does cardiac output change during pregnancy?
- Increased blood volume during pregnancy = increased CO
- HR also accelerates 15-20 bpm by 32 weeks of gestation (normal)
Cardiac output is highest when
The woman is lying on her side.
Cardiac output is lower in what positions?
Standing and supine positions
How does systemic vascular resistance change in pregnancy?
- Falls during pregnancy (ELEVATED BP DURING PREGNANCY IS NOT NORMAL)
- BP is affected by position (therefore important to record position during BP measurements)
Blood pressure is the lowest when the pregnant woman is in what position?
Lateral recumbent position
Blood pressure is higher when the pregnant woman is in what position?
Sitting.
How is systolic BP changed while a woman is sitting or standing?
Largely unchanged or decreased slightly
How is diastolic BP changed during pregnancy?
Shows a decrease that is greatest at 24-32 weeks.
How is arterial pressure changed when a pregnant woman lies in a side lying or supine position?
Is 10 mmHg lower than when sitting or standing.
Supine Hypotension
When the pregnant woman is in the supine position, particularly in the second and third trimesters, the weight of the gravid (pregnant) uterus partially occludes the vena cava and the aorta -> impedes return of blood from the lower extremities and consequently reduces cardiac return -> cardiac output may be reduced 25% to 30
What are the five major changes in blood flow during pregnancy?
- Blood flow is altered to include uteroplacental unit.
- Renal plasma flow increases to remove increased metabolic waste generated by mother & fetus.
- Woman’s skin requires increased circulation to dissipate heat generated by increased metabolism during pregnancy.
- Blood flow to the breast increases -> engorgement and dilated veins
- The weight of the expanding uterus of the inferior vena cava and iliac veins partially obstructs blood return from veins in the legs and the blood pools deep and superficial veins of the legs -> causes stasis of blood and venous distention.
How are blood components changed during pregnancy?
- Iron supplements should be taken to prevent iron deficiency anemia.
2. Leukocytes increase during pregnancy (12,000 cells/mm3 - 15,000 cells/mm3) and increase more during labor and early post party’s period (25,000-30,000 cells/mm3)
To compensate for the increased need for O2 during pregnancy, what does progesterone do?
Causes the woman to hyperventilate slightly by breathing more deeply, although her respiratory rate remains unchanged.
Assessment of the abdomen includes
- Progressive enlargement (McDonald’s measurement)
2. Fetal HR, BP and growth.
McDonald’s measurement
….
Always know CBC count
….
RPR “rapid plasma reagent”
Tests for syphilis.
Stat mandated test.
What causes slow peristalsis and motility of the GI tract during pregnancy?
- Increase in progesterone -> relax all smooth muscle -> decreases tone and motility.
- Small intestine takes longer to empty during late pregnancy which may allow additional time for nutrition to be absorbed.
What causes heartburn symptoms in pregnancy?
- Lower esophageal sphincter tone decreases during pregnancy d/t relaxant activity of progesterone on the smooth muscles.
- Also upward displacement of the stomach contributes to heartburn
What can cause gingivitis and bleeding gums in pregnant women?
Increased estrogen -> hyperemia of the tissues of the mouth and gums
Metabolism during pregnancy
Increased during pregnancy to meet demands of the growing fetus and its support system
What is the recommended weight gain for a pregnant woman who is underweight (BMI <18.5)?
28-40 lbs
PICCA
Eating non nutritive substances.
What is a normal weight gain for a pregnant woman with a normal weight (BMI 18.5-24.9)?
25-35 lb
What is a normal weight gain for a pregnant woman that is obese (BMI >30)?
11-15 lbs
