Pregnancy induces significant physiological changes to support fetal development and prepare the mother for labor. These changes affect multiple organ systems and can mimic medical conditions. Understanding these changes is crucial for distinguishing between normal physiological adaptations and pathological conditions. Key physiological changes include: Haematological changes: Plasma volume increases significantly, leading to a decrease in haemoglobin and haematocrit levels. Platelet counts may decrease, but are usually within normal limits. Iron, folate, and vitamin B12 requirements increase during pregnancy. The coagulation system becomes hypercoagulable, increasing the risk of venous thrombosis. Cardiac changes: Cardiac output increases by 20-40% during pregnancy, primarily due to increased stroke volume and heart rate. Blood pressure decreases in the first and second trimesters but rises in the third. Maternal position can affect cardiac output and uteroplacental blood flow, necessitating lateral positioning during pregnancy. Renal changes: Renal plasma flow and glomerular filtration rate increase, while renal vascular resistance decreases. Renal anatomy changes, including dilation of the ureters and calyces, leading to physiological hydronephrosis. Renal function is affected by hormonal changes, including relaxin and progesterone. Body water metabolism: Arterial under-filling stimulates the RAA system and sympathetic nervous system, leading to sodium and water retention. Plasma volume increases significantly, contributing to the hypervolaemic, hypo-osmolar state of pregnancy. Respiratory changes: Oxygen demand increases, leading to increased minute ventilation and a mild respiratory alkalosis. Diaphragmatic elevation reduces functional residual capacity, but vital capacity remains unchanged. Alimentary tract changes: Nausea and vomiting are common, possibly due to hormonal influences. Mechanical changes from the growing uterus affect gastrointestinal function, increasing the risk of reflux and nausea. Endocrine changes: Thyroid function is affected, with increased thyroxine-binding globulin and decreased free T3 and T4 levels. Adrenal function increases, with increased aldosterone and cortisol levels. The pituitary gland enlarges, with increased prolactin levels. Glucose metabolism: Pregnancy is diabetogenic, with increased insulin resistance and glucose shunting to the fetus. Lipid metabolism changes, with increased cholesterol and triglyceride levels. Protein metabolism increases, with increased protein intake and placental transfer of nutrients. Calcium metabolism: Calcium requirements increase, with increased intestinal absorption. Bone changes are minimal, with calcium drawn from the maternal skeleton in the third trimester. Skeletal and bone density changes: Pregnancy may lead to bone loss, but studies suggest no long-term association with osteoporosis. Bone turnover increases in the third trimester, with calcium sourced from the maternal skeleton. These physiological changes are essential for fetal development and maternal adaptation, but can be misinterpreted as pathological if not understood in the context of pregnancy. Understanding these changes is crucial for accurate diagnosis and managementPregnancy induces significant physiological changes to support fetal development and prepare the mother for labor. These changes affect multiple organ systems and can mimic medical conditions. Understanding these changes is crucial for distinguishing between normal physiological adaptations and pathological conditions. Key physiological changes include: Haematological changes: Plasma volume increases significantly, leading to a decrease in haemoglobin and haematocrit levels. Platelet counts may decrease, but are usually within normal limits. Iron, folate, and vitamin B12 requirements increase during pregnancy. The coagulation system becomes hypercoagulable, increasing the risk of venous thrombosis. Cardiac changes: Cardiac output increases by 20-40% during pregnancy, primarily due to increased stroke volume and heart rate. Blood pressure decreases in the first and second trimesters but rises in the third. Maternal position can affect cardiac output and uteroplacental blood flow, necessitating lateral positioning during pregnancy. Renal changes: Renal plasma flow and glomerular filtration rate increase, while renal vascular resistance decreases. Renal anatomy changes, including dilation of the ureters and calyces, leading to physiological hydronephrosis. Renal function is affected by hormonal changes, including relaxin and progesterone. Body water metabolism: Arterial under-filling stimulates the RAA system and sympathetic nervous system, leading to sodium and water retention. Plasma volume increases significantly, contributing to the hypervolaemic, hypo-osmolar state of pregnancy. Respiratory changes: Oxygen demand increases, leading to increased minute ventilation and a mild respiratory alkalosis. Diaphragmatic elevation reduces functional residual capacity, but vital capacity remains unchanged. Alimentary tract changes: Nausea and vomiting are common, possibly due to hormonal influences. Mechanical changes from the growing uterus affect gastrointestinal function, increasing the risk of reflux and nausea. Endocrine changes: Thyroid function is affected, with increased thyroxine-binding globulin and decreased free T3 and T4 levels. Adrenal function increases, with increased aldosterone and cortisol levels. The pituitary gland enlarges, with increased prolactin levels. Glucose metabolism: Pregnancy is diabetogenic, with increased insulin resistance and glucose shunting to the fetus. Lipid metabolism changes, with increased cholesterol and triglyceride levels. Protein metabolism increases, with increased protein intake and placental transfer of nutrients. Calcium metabolism: Calcium requirements increase, with increased intestinal absorption. Bone changes are minimal, with calcium drawn from the maternal skeleton in the third trimester. Skeletal and bone density changes: Pregnancy may lead to bone loss, but studies suggest no long-term association with osteoporosis. Bone turnover increases in the third trimester, with calcium sourced from the maternal skeleton. These physiological changes are essential for fetal development and maternal adaptation, but can be misinterpreted as pathological if not understood in the context of pregnancy. Understanding these changes is crucial for accurate diagnosis and management