Normal Pregnancy 1 Flashcards

Explain the maternal physiologic chanegs in pregnancy as a basis of how that can affect disease presentation.

1
Q

What are the changes to the uterus during pregnancy?

A
  • Total volume of urine contents at term range from 5-20L (10 mL when not pregnant)
  • Uterine weight about 1100g (vs. 70g)
  • Unergoes hypertrophy due to estrogen and maybe progesterone
  • Progressive increase in uteroplacental blood flow as gestation advances
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2
Q

What are the changes to the cervix during pregnancy?

A
  • Softens and undergoes cyanosis early on
  • Hypertrophy and hyperplasia of glands
    • eversion of proliferating columnar endocervical glands
  • Production of tenacious mucus rich in immunoglobulins which act as a protective barrier against normal vaginal bacteria
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3
Q

What are the changes to the vagina during pregnancy?

A
  • Chadwick sign - increased vaginal vascularity that accounts for bluish/purplish color during pregnancy
  • Increase in mucosal thickness
  • Loosening of connective tissue
  • Hypertrophy of smooth muscle cells
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4
Q

What are the changes to the ovaries during pregnancy?

A
  • Corpus luteum present and functional until 7 weeks gestation
  • Vascular pedicle increases from 0.6 cm outside of pregnancy to 2.6 cm at term
  • Decidual reaction
  • Luteoma -> exaggerated luteinization of ovary
  • May result in maternal virilization but without effect on fetus
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5
Q

What are the changes to the theca lutein cyst during pregnancy?

A
  • Exaggerated physiological follicle stimulation (hyperreactio luteinalis)
  • Usually bilateral cystic ovaries
  • Associated with high hCG levels (multiple gestation, GTD)
  • Maternal virilization occurs in 25% of patients with theca lutein cysts
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6
Q

What are the cardiac changes during pregnancy?

A
  • Elevation of diaphragm results in displacement of heart up and left
    • results in enlargement of cardiac silhouette on CXR
  • ~50% increase in circulating blood volume
  • ~15% increase in resting heart rate
  • ~20-50% increase in CO
  • **Increased heart rate **and decreased preload as a result
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7
Q

What are the vascular changes during pregnancy?

A
  • BP similar to pre-pregnant levels in first tirmester
    • ​Initial decrease in SVR
  • BP nadirs in second trimester
    • systolic decreases 5-10 mmHg
    • diastolic decreases 10-15 mmHg
  • BP increases back to baseline values in third trimester
    • Impairment of venous return by mechanical uterin obstruction overall increases SVR
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8
Q

What are the respiratory changes during pregnancy?

A
  • Diaphragm elevates, subcostal angle increases, and thoracic circumference increases
  • No change in respiratory rate
  • 40% increase in tidal volume
  • 20% decrease in residual volume and functional residual capacity
  • Dyspnea of pregnancy
    • Results from increased TV that lowers maternal PCO2, which is required for proper diffusion of CO2 from fetus to mother
    • Decreased PCO2 is compensated by increase excretion of bicarbonate
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9
Q

What are the gastrointestinal changes during pregnancy?

A
  • Displacement of stomach and intestines by enlarging uterus
  • Gastric emptying time unchanged during pregnancy, but increases substantially during labor (especially after administration of analgesics)
  • Liver itself has minimal changes except increased blood flow
  • Certain hepatic lab tests “abnormal” but related to pregnancy changes and not pathology
    • Alk phos
    • Albumin
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10
Q

What are the renal/urinary changes during pregnancy?

A
  • Slight increase in kidney size
  • GFR increases by up to 50% by mid-pregnancy, with even greater increases in RPF
  • Serum Cr decreases normally in pregnancy
  • Uterine displacement of ureters results in ureteral dilatation
  • Increased bladder pressure but with compensation by elongation of urethra, which increases intraurethral pressure and maintains continence
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11
Q

What is the purpose of hypervolemia in pregnancy?

A
  • Meets metabolic demands of the enlarged uterus and its hypertrophied vascular system
  • Provides nutrients to support rapidly growing placenta/fetus
  • Protects mother (and thus fetus) against deleterious effects of impaired venous return in supine and erect positions
  • Protects mother against adverse effects of blood loss associated with parturition
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12
Q

What are the changes to erythrocytes/hemoglobin in pregnancy?

A
  • Erythroid hyperplasia occurs and slight increase in reticulocyte count (not abnormally high)
  • Erythrocyte volume increases by about 450 mL by the end of pregnancy
  • Increase in erythrocytes not as great as increase in blood volume à slight decrease in Hb and Hct in pregnancy (Hb < 11.0 g/dL considered anemic)
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13
Q

What are the iron requirements of pregnancy?

A

1000 mg Fe required for pregnancy, with about 1/3 transferred to fetus and placenta

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14
Q

How do leukocytes change in pregnancy?

A
  • Varies considerably in pregnancy, but not abnormal for slight leukocytosis to be present
  • Distribution of cell types altered in pregnancy
    • ↑ granulocytes and CD8 lymphocytes
    • ↓ CD4 lymphocytes and monocytes
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15
Q

What are the changes to coagulation/firbrinolysis during pregnancy?

A
  • Both augmented but remain balanced to maintain homeostasis
  • All clotting factors increase with exception of factor XI and factor XIII
  • Protein S decreases in pregnancy, as does activated protein C
  • tPA increases throughout pregnancy
  • Minimal decrease in platelet count in pregnancy (attributed to hypervolemia)
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16
Q

What are the endocrine changes in pregnancy?

A
  • Number of circulating hormones increased in pregnancy
    • Estrogen
    • Progesterone
    • Prolactin
    • PTH
    • Aldosterone
    • Cortisol
    • DHEA
    • Androstenedione
    • Testosterone
  • Thyroid
    • TBG increases with pregnancy
    • Total T4 and total T3 increase in pregnancy, but TSH and TRH remain stable