Evelyn M. Hickson, RN, MSN, CNS, WCC

1. Evelyn M. Hickson, RN, MSN, CNS, WCC

2. Objectives • Describe the physiological changes that occur during pregnancy. • Identify changes in the lab values that occur during pregnancy as a result of normal physiological adaptation. • Identify abnormal laboratory values for the pregnant woman and the underlying physiology.

3. Physical Changes The most obvious changes in pregnant women are physical. Fetal growth and enlargement of the uterus causes the rearrangement and compression of most abdominal organs.

4. Cardiovascular • 45-50% increase in blood volume and cardiac output by term • This contributes to the hyper-coagulability of pregnancy and an increased risk of DVT due to increased clotting factors present in plasma. • Hypertrophy of both atria in the heart • Common to auscultate dysrthymias or murmurs • Heart rate increases 8-15 bpm above baseline

5. Cardiovascular • Late in pregnancy the inferior vena cava is completely occluded in the supine position. • Cardiac output is highest in lateral and knee-chest position. • Prior to 24 weeks the effect of supine position is not observed. • Blood pressure • Decrease occurs by 8 weeks and into the second trimester and then gradually returns to nearly pre-pregnant level by end of the third trimester.

6. Uterine Blood Flow Non-pregnant = 35 ml/min 10 weeks = 50 ml/min 28 weeks = 125 ml/min Term = 500 – 1000 ml/min By the end of pregnancy 1/6th of total maternal blood volume is contained in the vascular system of the uterus

7. Renal • Kidney and ureters • Dilation more prominent on right. • May last up to 3 months postpartum. • Increased risk of pyleonephritis. • Bladder • Decreased tone and increased capacity • Displaced in late pregnancy • Increased risk of UTI • Renal blood flow increases 35 – 60% • Increase GFR results in excretion of glucose, urea, uric acid, & calcium

8. Pulmonary • Mechanical changes • Enlarging uterus pushes on diaphragm and compresses the space available for respiration • Biochemical changes • Progesterone and Relaxin relaxing the smooth muscles, joints and cartilage. • The physiological dyspnea results in hyperventilation , lower pCO2, and maternal respiratory alkalosis. • The lower pH facilitates the release of oxygen from mother to fetus.

9. Gastrointestinal Estrogen causes increased blood flow to the mouth, making the gums friable and contributing to gingivitis. The saliva becomes more acidic. The tone of the lower esophageal sphincter decreases due to progesterone, causing smooth muscle relaxation, increasing heartburn and reflux.

10. Gastrointestinal • Compression of abdominal organs and hormonal changes lead to delayed gastric and intestinal emptying and increasing flatulence. • Cholestasis and cholelithiasis of pregnancy

11. Skin • Changes in pigmentation occurring in up to 90% of pregnancies • Chloasma (mask of pregnancy) • Linea nigra • Darkening of areola, umbilicus, vulva, and perianal skin. • Pigmented nevi, freckles and recent scars may deepen in color. • Sweat glands become hyperactive

12. Skin changes • Pruitic Urticaric Papules and Plaques of Pregnancy (PUPPS)

13. Hair • Mild degrees of hirsutism are common during pregnancy. • During normal pregnancy the proportion of hair in the growth phase is increased compared to that in the rest phase. • After delivery, the number of hairs entering the rest phase increase and it is normal to see a marked increase in scalp hair loss 2 to 4 months after delivery.

14. Breasts The breasts begin to change early in pregnancy, with tenderness, tingling sensations, and a feeling of heaviness within 4 weeks of the last menstrual period. The breasts rapidly enlarge with ductal growth stimulated by estrogen and alveolar hypertrophy stimulated by progesterone. Colostrum is present as early as 16 weeks.

15. Eye Increased thickness of cornea Decreased intraocular pressure Common for prescriptions to change during pregnancy, sometimes for the better.

16. Skeletal and Postural • Lordosis - Progressive increase in anterior convexity of the lumbar spine. • Changes in the center of gravity occur due to the shifting of weight and growth of the fetus. • Ligaments of the pubic symphysis and sacroiliac joints loosen and those suspending the uterus lengthen during pregnancy

17. Laboratory values

18. Hemoglobin & Hematocrit • Normal values for a non-pregnant adult woman • Hct 36-48 and Hgb 12-16 • During pregnancy the lower limits of normal

19. Lab valuesThyroid function

20. Lab values: ABG

21. Lab values: CBC

23. Lab Values: Urine

24. References American Thyroid Association. (2005). Thyroid disease and pregnancy. Retrieved February 23, 2005 from http://www.thyroid.org/patients/brochures/Thyroid_Dis_Pregnancy_broch.pdf. Gabbe, S.G., Niebyl, J. R., Simpson, J. L., Senkarik, M., & Cooley, M. (Eds.). (2001). Obstetrics: Normal and Problem Pregnancies (4th ed.). New York:  Churchill Livingston Varney, H., Kriebs, J.M. & Gegor, C. (2004). Varney's Midwifery (4th ed.). Boston:  Jones and Bartlett Inturrisi, M. (ed.). (2003). Labor & Delivery In My Pocket: An Emergency Reference (2nd ed.). Mesa, AZ:  In My Pocket Books, Inc. Somani, S., Bhatti, A., Ahmed, I.K. (2008). Pregnancy, Special Considerations. Retrived February 23, 2010 from http://emedicine.medscape.com/article/1229740-overview.