Urinary hCG patterns during the week following implantation
Authors: Nepomnaschy, P.A.; Weinberg, C.R.; Wilcox, A.J.; Baird, D.D.
Source: Human Reproduction, Volume 23, Number 2, 23 February 2008 , pp. 271-277(7)
Publisher: Oxford University Press
Abstract:BACKGROUNDHuman chorionic gonadotrophin (hCG) is used to monitor pregnancy status. Yet the pattern of hCG excretion in the first week following implantation has not been adequately described.Therefore the aim of this study was to describe the average profile of hCG and its variability during the 7 days following estimated implantation in a population of naturally conceived pregnancies.METHODSWe measured daily hCG concentrations in first-morning urine for 142 clinical pregnancies from women with no known fertility problems. Mixed-effects regression models were used to estimate the hCG trajectory and its variability in relation to pregnancy outcomes.RESULTShCG rose 3-fold between the day of detection and the next day (95 CI 2.73.4). The relative rate of rise decreased thereafter, reaching 1.6-fold (95 CI 1.51.8) between days 6 and 7. HCG levels followed a log-quadratic trajectory, and the patterns of rise were unrelated to number of fetuses, risk of spontaneous abortion or sex of the baby. Later implantations (after 10 luteal days) produced slower rates of increase.CONCLUSIONSAlthough mean hCG follows a log-quadratic trajectory during the first week of detectability, there is high variability across pregnancies. Later implantation may reflect characteristics of the uterus or conceptus that slow hCG production.
Document Type: Research article
Publication date: 2008-02-23
- Human Reproduction features full-length, peer-reviewed papers reporting original research, clinical case histories, as well as opinions and debates on topical issues. Papers published cover the scientific and medical aspects of reproductive physiology and pathology, endocrinology, andrology, gonad function, gametogenesis, fertilization, embryo development, implantation, pregnancy, genetics, genetic diagnosis, oncology, infectious disease, surgery, contraception, infertility treatment, psychology, ethics and social issues. The highest scientific and editorial standard is maintained throughout the journal along with a rapid rate of publication.