📘 Chapter 2: Pregnancy
✅ Definition:
Pregnancy is the condition that starts from conception (fertilization) and continues until the onset of labor.
- Total Duration: 9 months / 40 weeks / 280 days
- It is divided into three trimesters:
| Trimester | Duration |
|---|
| 1st Trimester | 0 to 12 weeks |
| 2nd Trimester | 13 to 28 weeks |
| 3rd Trimester | 29 to 40 weeks |
📅 Expected Date of Delivery (EDD) – Naegele’s Formula
EDD = LMP (First day of Last Menstrual Period) + 7 days – 3 months + 1 year
🔄 Physiological Changes in Pregnancy
1. Gastrointestinal System
- Appetite: Generally normal or slightly increased.
- Pica: Craving for non-food items like chalk, clay.
- Gums: Become soft, swollen, may bleed — Epulis Gravidarum.
- Stomach: Nausea & vomiting common due to progesterone.
- Gastric acid: Decreased initially; increases later.
- Small intestine: Slow motility → increased iron absorption.
- Large intestine: Sluggish → constipation, hemorrhoids.
- Gallbladder: Delayed emptying → risk of gallstones.
2. Respiratory System
- Nasal congestion and nosebleeds due to increased blood flow.
- Diaphragm rises; chest expands by 5–7 cm.
- Oxygen consumption increases by 20%.
- Dyspnea of pregnancy: Common, not dangerous.
3. Skin Changes
- Hyperpigmentation: Nipples, areola, linea nigra, axillae, perineum.
- Melasma / Chloasma: “Mask of pregnancy” on face.
- Striae Gravidarum: Stretch marks on abdomen, thighs.
- Palmar erythema: Redness of palms due to estrogen.
- Spider angiomas: Dilated blood vessels.
4. Breast Changes
- Increase in size, tenderness.
- Darkening of areola and nipples.
- Montgomery’s tubercles become prominent.
- From 12 weeks: Colostrum (yellowish secretion) may be present.
5. Urinary System
- Increased frequency of urination.
- GFR (Glomerular Filtration Rate) increases by 50%.
- Risk of UTI (Urinary Tract Infection) increases.
- Mild glucosuria may occur.
6. Cardiovascular System
- Heart size increases by ~10%.
- Cardiac Output (CO) increases by 30–50%.
- Heart Rate increases by 15–20 bpm.
- Blood pressure remains stable but may drop slightly in early pregnancy.
7. Hematological Changes
| Component | Non-Pregnant | Pregnant | Change |
|---|
| Blood Volume | 4000 ml | 5500 ml | ↑ Increased |
| Plasma Volume | 2500 ml | 3750 ml | ↑ Increased |
| RBC Volume | 1400 ml | 1750 ml | ↑ Increased |
| Hemoglobin | ~12 g/dl | Slightly ↓ | Dilutional Anemia |
| ESR | 10 mm/hr | 40 mm/hr | ↑ Increased |
| WBC | Normal | Increased | ↑ |
| Platelets | Slightly ↓ | | ↓ |
8. Endocrine System
- Thyroid gland enlarges by ~15%.
- Hormones like TSH, hCG, estrogen, progesterone increase.
- Insulin resistance develops due to HPL.
📊 Important Pregnancy Hormones
| Hormone | Source | Function |
|---|
| hCG | Trophoblast | Maintains corpus luteum, confirms pregnancy |
| hPL | Placenta | Anti-insulin, increases glucose to fetus |
| Estrogen | Placenta | Uterine growth, blood supply, breast dev. |
| Progesterone | Corpus luteum → Placenta | Relaxes uterus, maintains pregnancy |
| Relaxin | Corpus luteum, Placenta | Relaxes pelvic ligaments during labor |
⚖️ Weight Gain During Pregnancy
- Total recommended gain: 10–12 kg
| Component | Approx. Weight |
|---|
| Fetus | 3.0 kg |
| Placenta + Amniotic Fluid | 1.3 kg |
| Uterus | 1.0 kg |
| Breasts | 1.0 kg |
| Blood Volume | 1.3 kg |
| Fat & Protein Stores | 3.5–4.0 kg |
Kritika Group Of College, Bareilly
