Physiological changes during pregnancy

Physiological changes during pregnancy

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Pregnancy brings extensive physiological changes across multiple body systems. These adaptations are essential to support fetal development, maternal health, and the demands of labor and delivery. Most changes are regulated by hormones such as estrogen, progesterone, human chorionic gonadotropin (hCG), and prolactin. Below is a system-wise explanation of these changes.

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Physiological Changes
1– Cardiovascular Changes
2– Respiratory Changes
3– Renal and Urinary System Changes
4– Gastrointestinal Changes
5– Endocrine and Metabolic Changes
6– Hematologic Changes
7– Musculoskeletal and Postural Changes
8– Skin and Pigmentation Changes
9– Breast and Reproductive System Changes

Cardiovascular Changess

Cardiac output increases by up to 50% due to elevated heart rate and stroke volume. Blood volume expands by 30–50% leading to physiological anemia. Systemic vascular resistance decreases, often lowering blood pressure in early pregnancy. A systolic murmur may be heard, and there is increased risk of varicose veins and edema due to venous stasis.

Respiratory Changes

Progesterone stimulates increased respiratory drive, leading to higher tidal volume and minute ventilation. Oxygen consumption increases by 20%. Although respiratory rate remains stable, mild respiratory alkalosis may occur. The diaphragm elevates due to uterine enlargement, but lung function is generally preserved.

Renal and Urinary System Changes

Renal blood flow and glomerular filtration rate increase by 40–60%, enhancing clearance of waste products. Ureters and renal pelvis dilate, especially on the right, leading to physiological hydronephrosis. There is increased urinary frequency and a higher risk of urinary tract infections.

Gastrointestinal Changes

Hormonal effects, especially from progesterone, slow gastrointestinal motility, leading to constipation and reflux. Nausea and vomiting (morning sickness) are common in the first trimester. Gallbladder motility is reduced, increasing the risk of gallstones.

Endocrine and Metabolic Changes

There is increased activity of the thyroid and adrenal glands. Insulin resistance develops in the second half of pregnancy, influenced by placental hormones, potentially leading to gestational diabetes. Basal metabolic rate rises to meet fetal and maternal energy demands.

Hematologic Changes

Red cell mass increases, but plasma volume rises more significantly, causing dilutional (physiological) anemia. White blood cell counts may be elevated. There is a hypercoagulable state due to increased clotting factors, reducing hemorrhage risk but increasing thromboembolic risk.

Musculoskeletal and Postural Changes

Relaxin and progesterone cause ligamentous laxity, especially in the pelvis. The growing uterus shifts the center of gravity, causing lumbar lordosis and back pain. These adaptations prepare the body for delivery but may result in discomfort.

Skin and Pigmentation Changes

Estrogen and melanocyte-stimulating hormone cause hyperpigmentation, including linea nigra and melasma. Stretch marks (striae gravidarum) may appear due to rapid skin stretching. Increased blood flow may cause skin warmth and redness.

Breast and Reproductive System Changes

Breast enlargement, tenderness, and darkening of the areolae occur due to hormonal stimulation. Colostrum may be produced in late pregnancy. The uterus grows exponentially, and the cervix softens (Goodell’s sign) and becomes more vascular (Chadwick’s sign).

Physiological changes during pregnancy

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Note: If you select English, answer all questions in English.
यदि आप हिंदी चुनते हैं, तो सभी प्रश्न हिंदी में हल करें।

1. What happens to the total blood volume during pregnancy? 1. गर्भावस्था के दौरान कुल रक्त मात्रा में क्या परिवर्तन होता है?

A. Decreases slightly / थोड़ा घटती है
B. Remains unchanged / अपरिवर्तित रहती है
C. Increases by about 30–50% / लगभग 30–50% बढ़ जाती है
D. Doubles completely / पूरी तरह दोगुनी हो जाती है

2. Which cardiovascular change is commonly observed in pregnancy? 2. गर्भावस्था में आमतौर पर कौन सा हृदय संबंधी परिवर्तन देखा जाता है?

A. Decreased cardiac output / हृदय उत्पादन में कमी
B. Increased systemic vascular resistance / प्रणालीगत प्रतिरोध में वृद्धि
C. Increased heart rate / हृदय गति में वृद्धि
D. Hypertension is expected / उच्च रक्तचाप सामान्य है

3. Why is physiological anemia common during pregnancy? 3. गर्भावस्था में शारीरिक एनीमिया सामान्य क्यों होता है?

A. Reduced iron absorption / लोहे का अवशोषण कम
B. Increased destruction of red cells / लाल कोशिकाओं का अधिक विनाश
C. Plasma volume increases more than red cell mass / प्लाज्मा वॉल्यूम की वृद्धि
D. Fetal blood steals maternal hemoglobin / भ्रूणीय रक्त मातृ हीमोग्लोबिन लेता है

4. How does respiratory physiology adapt during pregnancy? 4. गर्भावस्था में श्वसन शरीरक्रिया विज्ञान कैसे अनुकूल होता है?

A. Tidal volume decreases / टाइडल वॉल्यूम घटता है
B. Respiratory rate decreases / श्वसन दर घटती है
C. Minute ventilation increases / मिनट वेंटिलेशन बढ़ता है
D. Vital capacity decreases / वाइटल कैपेसिटी घटती है

5. What renal change occurs in normal pregnancy? 5. सामान्य गर्भावस्था में गुर्दे में क्या परिवर्तन होता है?

A. Decrease in GFR / GFR में कमी
B. Increase in renal plasma flow and GFR / RPF और GFR में वृद्धि
C. Reduced urine output / मूत्र उत्पादन में कमी
D. Kidney size decreases / गुर्दे का आकार घटता है

6. Which gastrointestinal change is typical during pregnancy? 6. गर्भावस्था में कौन सा जठरांत्र परिवर्तन सामान्य होता है?

A. Increased gastric emptying / गैस्ट्रिक खाली होना बढ़ता है
B. Reduced gallstone formation / पित्ताशय की पथरी कम बनती है
C. Relaxation of lower esophageal sphincter / निचले इसोफेजियल स्फिंक्टर में शिथिलता
D. Increased intestinal motility / आंतों की गति बढ़ती है

7. What hormone maintains early pregnancy? 7. प्रारंभिक गर्भावस्था को बनाए रखने वाला हार्मोन कौन सा है?

A. Estrogen / एस्ट्रोजन
B. Oxytocin / ऑक्सीटोसिन
C. Progesterone / प्रोजेस्ट्रोन
D. Prolactin / प्रोलैक्टिन

8. What happens to blood pressure in early pregnancy? 8. प्रारंभिक गर्भावस्था में रक्तचाप में क्या परिवर्तन होता है?

A. Increases consistently / लगातार बढ़ता है
B. Decreases slightly due to vasodilation / रक्त वाहिकाओं के फैलने से थोड़ा घटता है
C. Remains constant / स्थिर रहता है
D. Becomes highly variable / बहुत अधिक परिवर्तनीय होता है

9. Why are UTIs more common in pregnancy? 9. गर्भावस्था में मूत्र संक्रमण अधिक क्यों होते हैं?

A. Stronger immune system / मजबूत प्रतिरक्षा प्रणाली
B. Decreased bladder capacity / मूत्राशय की क्षमता कम
C. Urinary stasis and tract dilation / मूत्र रुकावट और मूत्र पथ का फैलाव
D. Frequent urination flushes bacteria / बार-बार पेशाब से बैक्टीरिया निकल जाते हैं

10. What coagulation change occurs during pregnancy? 10. गर्भावस्था में कौन सा रक्तस्रवण परिवर्तन होता है?

A. Reduced clotting factor production / क्लॉटिंग फैक्टर कम बनते हैं
B. Increased fibrinolysis / फाइब्रिनोलिसिस बढ़ता है
C. Hypercoagulable state / हाइपरकोएगुलेबल स्थिति
D. Increased bleeding tendency / रक्तस्राव की प्रवृत्ति बढ़ती है