Physiology of Pregnancy
Case Study
- Patient: Jenny, 25-year-old, Gravita 1 para-zero female
- Gestation: 34 weeks
- Symptoms: Increased difficulty in taking deep breaths, no shortness of breath on exertion, no chest pain
- History: Uncomplicated pregnancy, no medical problems
- Discussion Point: What is the most likely cause of her difficulty in breathing?
Physiological Changes During Pregnancy
Eight systems to focus on:
- Cardiovascular
- Hematologic
- Respiratory
- Gastrointestinal
- Renal
- Metabolic
- Endocrine
- Anatomic changes
Cardiovascular System
- Anatomical Changes:
- Heart is displaced left and upward, rotated on its long axis
- Location for heart sound auscultation changes
- Physiological Changes:
- Systemic Vascular Resistance: Decreases
- Blood Pressure: Decreases in first and second trimesters
- Mean Arterial Pressure: Decreases
- Heart Rate: Increases
- Cardiac Output: Increases by 15% to 40% in the first trimester; more during labor
Hematologic System
- Blood Volume: Increases 40% to 45%
- Increase in erythrocytes and plasma
- Leads to physiologic anemia
- Iron Requirements: Increase, may require supplementation
- Immune System: Blunted, pregnancy is an immunodeficient state
- Hypercoagulability:
- Increased risk for deep vein thrombosis (DVT) and pulmonary embolism
- Important in context of C-sections and surgery
Respiratory System
- Anatomical Changes:
- Diaphragm rises by 4 cm due to enlarging uterus
- Physiological Changes:
- Functional Residual Capacity: Decreases
- Total Lung Volume: Does not change
- Expiratory Residual Volume & Residual Volume: Decrease
- Tidal Volume & Minute Ventilation: Increase
Question
- Question: During pregnancy, which physiologic changes happen within the pulmonary system?
- A) Total lung capacity decreases
- B) Inspiratory capacity decreases
- C) Residual volume decreases
- D) None of the above
- Answer: C) Residual volume decreases due to uterine compression and diaphragm displacement
Summary
- Pregnancy affects multiple body systems, with significant cardiovascular, hematologic, and respiratory changes.
- Understanding these changes helps address symptoms and risks related to pregnancy, such as Jenny's breathing difficulty.