Maternal urine beta-core hCG fragment level and small for gestational age neonates

Nausea and vomiting of pregnancy: endocrine basis and contribution to pregnancy outcome

For a majority of women, nausea and vomiting of pregnancy (NVP) is an unpleasant but normal feature of pregnancy. NVP has a largely unknown etiology, but it is widely agreed that physiological, psychological, genetic, and cultural components are contributing factors. The occurrence of NVP may be of benefit in pregnancy, and NVP-associated pregnancies are less likely to result in miscarriage, preterm delivery, or intrauterine growth retardation. It has been suggested that NVP is promoted by secretion of human chorionic gonadotrophin (hCG), largely on the basis of the coincidence between the onset of NVP and hCG secretion and the peaks of both at around 12 to 14 weeks' gestation. Concentrations of hCG that are above or below the normal range are associated with poor pregnancy outcomes. It seems that NVP and hCG are related and that nutrient restriction during critical periods of embryonic development may ensure production of hCG at optimal levels, protect placental development, and optimize nutrient partitioning between maternal and fetal tissues.

Immunochemical measurement of early pregnancy isoforms of HCG: potential applications to fertility research, prenatal diagnosis, and cancer

Human chorionic gonadotropin, the glycoprotein hormone of pregnancy, is found naturally in blood and urine in a variety of isoforms. These variants are related to both peptide bond cleavages (such as the nicked forms of hCG) and the beta core fragment urinary metabolite, as well as the larger variety of species resulting from carbohydrate heterogeneity. We have recently developed immunoassay systems that can measure nicked forms of hCG (antibody B151) as well as particular high carbohydrate variants (hyperglycosylated forms) of hCG (B152), which are associated with cancers producing hCG. Using the assay system for nicked hCG, we found that nicked hCG does not appear to be present as a significant hCG isoform during normal pregnancies if the urine specimens are well preserved. Applying the assay for hyperglycosylated hCG isoforms, we discovered that these forms are prevalent during very early pregnancy and decline rapidly to low concentration after the first 6 weeks of pregnancy. Persistence of these early pregnancy forms does not bode well for the pregnancy. Other investigators report that measurement of such hCG isoforms may aid in diagnosis of Down syndrome pregnancies. In summary, measurement of the hyperglycosylated hCG isoforms are useful for evaluation of healthy progress of normal pregnancy, as an additional detection marker for Down syndrome pregnancies, and as a potential new marker of trophoblastic malignancy. New reference preparations will soon be available for the calibration of assay systems for measurement of many of these hCG variants and metabolites.