Maternal weight gain during pregnancy can be attributed primarily to increases in maternal body water and fat. On average, weight gain at term is distributed as follows:
- Fetus: 7 to 8 pounds (3.2 to 3.6 kg)
- Fat stores: 6 to 8 pounds (2.7 to 3.6 kg)
- Increased blood volume: 3 to 4 pounds (1.3 to 1.8 kg)
- Increased fluid volume: 2 to 3 pounds (0.9 to 1.3 kg)
- Amniotic fluid: 2 pounds (0.9 kg)
- Breast enlargement: 1 to 3 pounds (0.9 to 1.3 kg)
- Uterine hypertrophy: 2 pounds (0.9 kg)
- Placenta: 1.5 pounds (0.7 kg)
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