CLINICAL BIOCHEMISTRY OF PREGNANCY

Major adaptations in maternal physiology and metabolism are required f or successful pregnancy outcome. Hormonal changes initiated even befor e conception significantly alter maternal biochemistry early in pregna ncy. Steroid hormones, peptide hormones, and prostaglandins interact t o expand blood and plasma volume and modulate the maternal capacity to supply energy and nutrients to the fetoplacental unit. As gestation p rogresses, reference ranges for the concentration of many biochemical parameters change significantly from those found in the nonpregnant st ate. Gestation-specific reference ranges are essential for correct int erpretation of tests used in screening, diagnosis, and monitoring duri ng pregnancy. The use of clinical laboratory tests in the management o f high-risk pregnancy are discussed from the perspective of testing be fore conception and during pregnancy.