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Start Over Author "van Montfrans J" Journal human reproduction
4 results on '"van Montfrans J"'

3. Basal FSH concentrations as a marker of ovarian ageing are not related to pregnancy outcome in a general population of women over 30 years.

Author

van Montfrans, J M, van Hooff, M H A, Huirne, J A, Tanahatoe, S J, Sadrezadeh, S, Martens, F, van Vugt, J M G, and Lambalk, C B

Abstract

Background: Previous studies suggest that elevated basal FSH concentrations are related to aneuploid pregnancies. However, there have been no prospective studies evaluating the incidence of aneuploidies in relation to basal FSH concentrations. Since the majority of aneuploid conceptions end in early pregnancy loss or abortion of a recognized pregnancy, these determinants are appropriate intermediate end-points to study aneuploidy.Methods: We performed a prospective study in 129 women without a history of subfertility pursuing a spontaneous pregnancy. Basal FSH concentrations were measured during three menstrual cycles. Urinary HCG levels were measured during menstruation for a maximum of six menstrual cycles, to detect early pregnancy loss. We estimated the effect of basal FSH concentrations on pregnancy outcome, taking into account possible confounders.Results: We observed no significant effect of basal FSH concentrations on the incidence of early pregnancy loss or abortion of clinically recognized pregnancies.Conclusions: We conclude that in a population of women without a history of subfertility, pursuing a spontaneous pregnancy, basal FSH concentrations are not related to the incidence of early pregnancy loss or abortions. This prospective study therefore fails to confirm a relationship between signs of decreased ovarian reserve and aneuploid pregnancies. [ABSTRACT FROM AUTHOR]

Published
2004

4. Are elevated FSH concentrations in the pre-conceptional period a risk factor for Down's syndrome pregnancies?

Author

van Montfrans, J M, Lambalk, C B, van Hooff, M H, and van Vugt, J M

Abstract

Recent publications have reported a relation between a decreased ovarian reserve and Down's syndrome pregnancies. Using the data of a case-control study into risk factors for a Down's syndrome pregnancy, we estimated the usefulness of pre-conceptional basal follicle stimulating hormone (FSH) screening (detection rate, false positive rate, positive and negative likelihood ratio, as well as the loss rate of unaffected pregnancies) to identify Down's syndrome pregnancies. The optimal detection rate of pre-conceptional basal FSH screening for Down's syndrome pregnancies was 14%, corresponding to a false positive rate of 5% and a positive likelihood ratio of 2.8. Incorporation of basal FSH screening into the regimen of first trimester serum screening followed by nuchal translucency measurement would increase the detection rate from 85 to 87%. However, basal FSH screening alone or in combination with other screening methods would cause an unacceptably high loss rate of unaffected pregnancies compared with current screening protocols, indicating that routine pre-conception basal FSH screening would not be useful to identify women at risk for a Down's syndrome pregnancy. However, when elevated basal FSH concentrations are diagnosed during subfertility evaluation, an elevated risk for a Down's syndrome pregnancy could be discussed with women who become pregnant.

Published
2001
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