Maternal Changes in Pregnancy

Summary

This video delves into the physiological changes in pregnancy, focusing on the maternal body's adaptations. It covers cardiovascular shifts like a 30-50% increase in cardiac output and a rise in heart rate, leading to potential blood pressure drops. The script also addresses respiratory changes, including a 40% rise in tidal volume, and renal adjustments like increased GFR. Gastrointestinal effects are highlighted, such as decreased GI motility leading to constipation and risk of hemorrhoids. Hematological changes include a significant plasma volume increase and a rise in blood's hypercoagulability, posing risks like deep vein thrombosis.

Takeaways

• 💓 **Cardiovascular Changes**: Cardiac output increases by 30-50% during pregnancy, peaking in the third trimester due to rising estrogen levels.
• 🔍 **Renal Fluid Reabsorption**: Estrogen stimulates the kidneys to reabsorb more fluid into the vascular space, increasing blood volume and preload.
• 🚀 **Stroke Volume**: The right ventricle stretches to accommodate increased blood volume, leading to higher stroke volume and cardiac output.
• 📈 **Heart Rate**: Heart rate increases in pregnancy but typically doesn't exceed 100 beats per minute.
• 🩸 **Blood Pressure**: Despite increased cardiac output and heart rate, blood pressure decreases due to progesterone-induced vasodilation.
• 🌊 **Venous Return**: Uterine growth can compress the inferior vena cava after 20 weeks, decreasing preload and potentially causing varicose veins and swelling.
• 😖 **Symptoms**: Pregnancy can cause symptoms like palpitations, lightheadedness, and increased risk of anemia due to the physiological changes.
• 🌬️ **Respiratory Changes**: Tidal volume increases by 40% by the end of the first trimester due to increased oxygen consumption and progesterone's effect on respiration.
• 💨 **Respiratory Alkalosis**: Pregnant patients may experience respiratory alkalosis due to increased minute volume and decreased CO2 levels.
• 💧 **Renal Changes**: Progesterone increases vasodilation and GFR, leading to more urine production and potential hydronephrosis.
• 🍽️ **Gastrointestinal Effects**: Progesterone decreases GI motility, potentially causing GERD, constipation, and an increased risk of hemorrhoids.
• 🩸 **Hematological Changes**: Plasma volume increases by 40-50%, but red blood cell production increases less, which can lead to anemia.
• 🔗 **Hypercoagulability**: Pregnancy increases the risk of blood clots due to higher procoagulant factors, platelet aggregation, and potential blood stasis.

Q & A

What is the primary cardiovascular change during pregnancy?

The primary cardiovascular change during pregnancy is a 30 to 50 percent increase in cardiac output, which peaks by the third trimester.

How does estrogen impact the cardiovascular system during pregnancy?

Estrogen stimulates the kidneys to reabsorb more fluid into the vascular space, leading to an increase in blood volume and preload, which in turn increases cardiac output.

What is the typical increase in heart rate during pregnancy?

The increase in heart rate during pregnancy varies by patient but is unlikely to exceed 100 beats per minute.

Why does blood pressure decrease in early pregnancy despite increased cardiac output and heart rate?

The decrease in blood pressure is due to progesterone, which stimulates the smooth muscle of the vascular tissue to dilate, resulting in a 20% decrease in systemic vascular resistance.

How does the growth of the uterus affect venous return during pregnancy?

After approximately 20 weeks gestation, the growing uterus can compress the inferior vena cava, decreasing preload and potentially leading to varicose veins and peripheral swelling.

What are common signs and symptoms related to cardiovascular changes in pregnant patients?

Common signs and symptoms include palpitations, lightheadedness, dizziness, exercise intolerance, and syncope due to decreased blood pressure and increased heart rate.

How does pregnancy affect the respiratory system?

Pregnancy leads to a 40% increase in tidal volume by the end of the first trimester, due to increased oxygen consumption and carbon dioxide production, as well as the effects of progesterone on the brainstem.

What is the consequence of the growing uterus compressing the diaphragm?

Compression of the diaphragm can lead to decreased functional residual capacity, increased potential for respiratory illnesses, and a state of chronic mild respiratory alkalosis.

How does progesterone affect the renal system during pregnancy?

Progesterone increases vasodilation, leading to an increase in glomerular filtration rate (GFR), which can result in increased urine production, hydronephrosis, and a higher risk of urinary tract infections.

What gastrointestinal changes occur due to increased progesterone levels during pregnancy?

Increased progesterone levels lead to decreased smooth muscle tone and decreased lower esophageal sphincter closure, resulting in increased gastric pressure, potential GERD, constipation, and an increased risk of hemorrhoids.

How does pregnancy affect hematological parameters?

Pregnancy causes a 40 to 50 percent increase in plasma volume and a 20 to 30 percent increase in red blood cell production, often leading to a relative anemia. It also increases the potential for hypercoagulability, putting patients at risk for deep vein thrombosis or pulmonary embolism.