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Post on 25-Dec-2014
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- 1. Physiological Changes in Pregnancy
Sandy Warner RNC OB, MSN
- 2. Adaptations
Nurses must understand the normal anatomical and physiological changes in pregnancy to recognize any deviation from normal.
In addition to physical changes, there are also psychological changes that occur with pregnancy.
- 3. Body system alterations
- 4. Cardiovascular
Cardiovascular adaptation affects all organ systems.
Cardiovascular anatomy and physiology changes to accommodate increasing maternal and fetal circulatory needs.
- 5. Heart
Heart is enlarged, displaced upward and rotates to the left.
PMI (point of maximal impulse) shifts to 4th
intercostal space and closer to the midclavicular line.
- 6. Heart sounds and rate:
Audible splitting of S1 and S2; S 3 becomes audible.
Benign systolic murmurs are common.
Heart rate increases 15-20 beats as pregnancy progresses.
- 7. Cardiac Output
Defined as the amount of blood pumped from the left ventricle into the aorta each minute.
(heart rate x stroke volume = CO)
In pregnancy increased by 40% by 36-38 wks.
- 9. Blood Pressure
Due to decreased systemic vascular resistance, blood pressure is lower at end
of 1st trimester and throughout 2nd, returning to baseline in 3rd trimester.
Also affected by renin-angiotensin-aldosterone system from kidneys.
- 10. Hematological Changes
Increase in WBCs and RBCs.
Increase blood volume for uterus, fetus and increased perfusion of other organs, especially kidneys.
Increased plasma volume ratio to RBC volume leads to hemodilution.
- 11. Hematological changes cont.
Decreased fibrinolytic activity
Platelets remain normal or might decrease slightly
Increased need for iron related to RBCs
- 12. Respiratory
Capillary dilation early in pregnancy causes
Engorgement of entire tract from nares to bronchi
- 13. Respiratory
Increased need for oxygen
Improved oxygen delivery
Compensatory respiratory alkalosis
- 14. Genitourinary
Kidneys increase in size and GFR.
Ureters dilate and elongate, becoming compressed by uterus.
Bladder tone decreases due to progesterone, becomes displaces as uterus grows.
- 15. Genitourinary
Urine flow accumulates and slows.
Increased renal excretion of BUN, creatinine and glucose.
Decreased serum BUN, creatinine and glucose.
Decreased tubular reabsorption of glucose.
Increased tubular reabsoption of sodium.
- 16. Genitourinary
Uterus rises out of pelvis during 1st trimester.
Weight increases from 70 gms to 1100 gms.
Volume at term averages 5 L but may be as
much as 20 L.
Individual cells increase 100 fold in length by term,
allowing for contractions and involution.
- 17. Genitourinary
Increases in mass and fluid content.
85% connective tissue and 15% smooth muscle.
Ripening occurs via softening and effacement with the influence of hormones.
- 18. Gastrointestinal
Mouth changes in tastes, increase in saliva production, gums swell and bleed easier.
Esophagus decreased tone leads to reflux.
Stomach decreased tone and motility.
Intestines smooth muscle relaxation and
decreased tone and motility - constipation
- 19. Gastrointestinal
Esophagus, stomach and intestines move as uterus grows.
Round ligament stretches as uterus expands.
Gallbladder decrease tone and motility
combined with increased emptying time can
cause increased risk of gallstones.
- 20. Gastrointestinal
Hyperemesis common in first trimester.
Strong sense of smell.
Increased saliva production.
Can persist throughout pregnancy.
- 21. Immunological
Placenta functions to help protect the fetus from infection with IgG.
Decreased Tcell activity with pregnancy that increases susceptibility to viral infections.
Immunity is enhanced by sleep/rest and decreased stress.
- 22. Musculoskeletal
Abdominal muscles relax and pelvis tilts forward.
Center of gravity shifts.
Joints relax waddling.
Muscle aches from increasing weight of uterus.
Posture change due to lumbodorsal curve of spine.
- 23. Musculoskeletal
Normal weight gain 25-35#.
Slight weight loss in 1st trimester from
nausea and vomiting.
Average 1#/wk weight gain in 2nd and 3rd trimesters.
- 24. Endocrine
Function increases to meet metabolic and growth needs.
Helps regulate calcium, phosphorus, Vit. D and magnesium concentration.
Increases in pregnancy to help skeletal growth.
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