Recurrent pre-clinical pregnancy loss is unlikely to be a 'cause' of unexplained infertility

Department of Reproductive Medicine and Gynaecology, University Medical Centre Utrecht, F05.126, PO Box 85500, 3508 GA Utrecht, The Netherlands.
Human Reproduction (Impact Factor: 4.59). 07/2011; 26(10):2636-41. DOI: 10.1093/humrep/der217
Source: PubMed

ABSTRACT A proportion of women with 'unexplained' infertility may present with subfertility because their pregnancies fail before they are clinically recognized. In order to test whether pre-clinical early pregnancy losses (EPL) occur more frequently in women with unexplained infertility, serial urinary hCG concentrations were measured to compare EPL per cycle rates following spontaneous conception in patients with unexplained infertility versus healthy volunteers.
Sixty patients under 39 years of age with unexplained infertility and 60 healthy controls, who were trying to conceive spontaneously, participated in this study. All participants were asked to collect daily urine samples from cycle day 14 until menstruation for three consecutive cycles or until a positive pregnancy test was obtained. Urinary hCG and creatinine levels were measured by immunoassay. Implantation was detected when urinary hCG levels rose above reference levels constructed from samples obtained from 12 women not attempting to conceive. EPL rates were determined by a linear mixed model using logarithmically transformed hCG/creatinine data.
In the 133 cycles of 60 women with unexplained infertility, just one implantation was detected, which became an ongoing pregnancy. In contrast, in 103 such cycles in 46 control patients, 30 implantations were detected (24 clinical pregnancies, 6 cases of EPL). The odds ratio for EPL/cycle in the unexplained versus control group was 0 (95% confidence interval: 0-0.795, P = 0.026).
Our data do not support the hypothesis that recurrent EPL may present as unexplained infertility. Post-implantation failure is therefore unlikely to contribute significantly to the presentation of subfertility.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Endothelial nitric oxide synthase (eNOS) has diverse roles in the female reproductive system including a role in blastocyst implantation. Aberrant expression of eNOS could therefore be significant in the pathogenesis of disorders of implantation. In this study, eNOS protein and mRNA levels in the endometrium of women with recurrent miscarriages, unexplained infertility and a control group were determined by compartmental quantitative immunohistochemistry and real-time reverse-transcription PCR. eNOS was found to be immunolocalized to all layers of the endometrium and vascular endothelium. eNOS protein was higher in glandular epithelium (P = 0.004) and luminal epithelium (P = 0.002), but not vascular endothelium and stroma, in women with recurrent miscarriage. Similarly, in women with unexplained infertility, eNOS was significantly higher (P < 0.03) in luminal epithelium but not in any other compartments compared with the control group. The levels of mRNA confirmed the protein data, demonstrating higher eNOS mRNA in the endometrium of women with recurrent miscarriage and unexplained infertility compared with controls. In conclusion, increased expression of eNOS in glandular and luminal epithelium of the endometrium in women with recurrent miscarriages and unexplained infertility suggests a detrimental effect of excess nitric oxide in endometrial receptivity and implantation. RBM Online (c) 2012, Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.
    Reproductive biomedicine online 07/2012; 25(4):408-14. DOI:10.1016/j.rbmo.2012.07.004 · 2.98 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Bleeding from endometriotic implants is now an established cause of acute hemoperitoneum in pregnancy. However, the adverse impact of pelvic endometriosis on uterine function before conception may also interfere with subsequent deep placentation, accounting for the increased risk of obstetrical complications, including preterm birth and antepartum hemorrhage.
    Fertility and sterility 03/2012; 98(1):30-5. DOI:10.1016/j.fertnstert.2012.02.024 · 4.30 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Despite expanding global experience with advanced reproductive technologies, the majority of IVF attempts do not result in a successful pregnancy, foremost as a result of implantation failure. The process of embryo implantation, a remarkably dynamic and precisely controlled molecular and cellular event, appears inefficient in humans and is poorly understood. However, insights gained from clinical implantation failure, early pregnancy loss, and emerging techologies that enable molecular interrogation of endometrial-embryo interactions are unravelling this major limiting step in human reproduction. We review current molecular concepts thought to underlie implantation failure, consider the contribution of embryonic and endometrial factors, and discuss the clinical value of putative markers of impaired endometrial receptivity. Finally we highlight the nature of the dialogue between the maternal endometrium and the implanting embryo and discuss the concept of natural embryo selection. This article is part of a Special Issue entitled: Molecular Genetics of Human Reproductive Failure.
    Biochimica et Biophysica Acta 06/2012; 1822(12). DOI:10.1016/j.bbadis.2012.05.017 · 4.66 Impact Factor