Hyperglycosylated human chorionic gonadotropin and the source of pregnancy failures

Objective To investigate the proportion of hyperglycosylated human chorionic gonadotropin (hCG-H) produced at the time of implantation as a predictor of pregnancy success. Design Measuring daily urine hCG and hCG-H on the day of implantation. The time of implantation was assumed to be the first day of hCG detection (total hCG >1 mIU/mL). Setting Urine samples were collected at volunteers' homes throughout city of Albuquerque. Patient(s) 110 women attempting to conceive spontaneously; 62 achieved pregnancies (42 to term and 20 failed). Intervention(s) None. Main Outcome Measure(s) Measurements of the total hCG and hCG-H, and calculations of the proportion of hCG-H. Result(s) In all 42 term pregnancies, the proportion of hCG-H on the day of implantation was >50%. This was also true for 7 of the 20 failures. Statistically significant lower proportions of hCG-H (50%) are required for successful growth and invasion by cytotrophoblasts at the time of implantation. Low proportions of hCG-H at implantation predict failure and are likely to be the root of many pregnancy failures. The 7 of 20 failures with normal proportions of hCG-H were likely due to genetic, immune, or maternal causes. Measurement of a proportion of hCG-H