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- William Forbes Hendry (25 August 1998)
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Postcoital testing
- M G R Hull (16 September 1998)
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William Forbes Hendry
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Sir, I was disappointed by the article by Oei et al on the post-coital test (1). These authors failed to mention the work of Kremer et al which demonstrated that the most common cause of unexplained poor post-coital test is due to auto-antibodies to spermatozoa in the male partner which prevent sperm penetration of cervical mucus (2). This affects the function of the spermatozoa not only in the partner's cervical mucus, but also in any woman's mucus, as can be demonstrated by crossed hostility testing (3). Failure to test for such antibodies, for example by routine MAR testing (4) of the male partner's spermatozoa, will leave observers just as confused about so-called "cervical hostility" as they were over 20 years ago. To do such a test without understanding the implications of the result, and then apply a treatment which does not work well for an unrecognised condition, is unlikely to achieve statistical significance. In fact, successful treatment is available for autoimmunity to spermatozoa in men, as demonstrated by double blind prospective controlled trial (5). The study by Oie et al failed to assess the male partner adequately. This places undue reliance on assisted reproductive techniques rather than critical evaluation of what is, in fact, wrong with the couple concerned - all very well for those that can afford it, but not very helpful for those that cannot. Yours sincerely, William Forbes Hendry, MD ChM FRCS, (Tel 0171 636 7426), Consultant Urologist St Bartholomew's Hospital London EC1A 7BE Reference List 1. Oie SG, Helmerhorst FM, Bloemenkamp KWM, Hollants FAM, Meerpoel DEM, Keirse MJNC. Effectiveness of the postcoital test: randomised controlled trial. Br med J 1998;317:502-5. 2. Kremer J, Jager S, Van Slochteren-Draaisma T. The 'unexplained' poor post coital test. Int J Fertil 1978;23:277-81. 3. Morgan H, Stedronska J, Hendry WF, Chamberlain GF, Dewhurst CJ. Sperm/cervical-mucus crossed hostility testing and antisperm antibodies in the husband. Lancet 1977;1:1228-30. 4. Hendry WF. Detection and treatment of antispermatozoal antibodies in men. Reprod.Fertil.Dev. 1989;1:205-22. 5. Hendry WF, Hughes L, Scammell G, Pryor JP, Hargreave TB. Comparison of prednisolone and placebo in subfertile men with antibodies to spermatozoa. Lancet 1990;335:85-8. |
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M G R Hull
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In their report on postcoital testing (PCT) Oei et al1 surprisingly applied randomised controlled trial method to the use (or not) of a diagnostic rather than therapeutic procedure, which is inappropriate. The findings were consequently unsurprising and their interpretation unfortunately misleading. A diagnostic procedure cannot alter outcome, except by successfully influencing the choice of treatment. Treatment effect was not studied by Oei et al, nor was an effect likely to have been found given the wide- ranging, non-specific, empirical approach to treating many of the causes of infertility. Oei et al describe intrauterine insemination (IUI) along with superovulation therapy as a specific treatment for couples with a negative PCT, but that is not so. IUI and in vitro fertilisation (IVF) for example are used as common solutions to a variety of fertility disorders, irrespective of sperm or cervical mucus function though success rates may vary. The only significant difference found by Oei et al was that the sum of the frequencies of more than five different types of treatment employed was greater by a small margin in the couples who had had a PCT done compared with those who had not (54% vs. 41%). No individual method was used significantly more frequently. By contrast, invasive investigations such as hysterosalpingography and laparoscopy appeared to have been used less frequently in the PCT group. In the PCT group Oei et al could find no significant difference in pregnancy rates between couples with a negative or positive PCT but took no account of possible treatment effects, nor (in that part of their analysis) of the likely possibility that couples who were intended to have a PCT but conceived too soon would have had a positive test result. Furthermore we are left to guess the authors' criterion for a positive PCT though they themselves have previously drawn attention to the 10-fold difference between criteria in use which have mostly been arbitrarily chosen. To evaluate a fertility test like the PCT, positive and negative test results need to be compared in terms of conception rates in couples with otherwise unexplained infertility receiving no treatment; alternatively after a particular treatment for a defined condition such as IVF for tubal disease. Age and duration of infertility would be key factors to be accounted. Using the properly derived criterion of one progressively motile spermatozoon per high power microscope field, there have been several studies describing the distinguishing power of the PCT for natural conception without treatment (see review2 and other reports3,4), but none were mentioned by Oei et al. Furthermore, comparative studies have demonstrated the overriding power of the PCT compared with semen analysis3,4 which has generally been shown to be a weak predictor of fertility except when sperm numbers are severely depleted. In-vitro testing of sperm-mucus interaction, which is closely related to the PCT, has also been shown by several studies to be prognostic for natural conception or to correlate with in-vitro fertilising ability of spermatozoa (reviewed2,3) providing a useful prognostic index for IVF treatment or the need for intracytoplasmic sperm injection (ICSI). Duration of infertility is a major factor affecting the chance of natural conception, particularly in unexplained infertility, determining how early in the course of infertility should treatment be applied, and whether it is needed at all. Couples with unexplained infertility, including a positive PCT, of duration less than 3 years have a demonstrably good chance of conceiving without treatment.5 They are essentially normal, having failed to conceive earlier due mainly to bad luck, and can be spared any active treatment other than advice. By contrast, couples with a negative PCT have a poor chance of conceiving naturally irrespective of their duration of infertility (unpublished data), presumably because they have a distinct cause - usually sperm disorder - therefore treatment is appropriate without delay. M G R Hull, Professor of Reproductive Medicine & Surgery, University of Bristol, Division of Obstetrics & Gynaecology, St Michael's Hospital, Bristol BS2 8EG, UK. J L H Evers. Professor of Obstetrics & Gynaecology, Academisch ziekenhuis Maastricht, 6202 AZ Maastricht, The Netherlands References 1. Oei SG, Helmerhorst FM, Bloemenkamp KWM, Hollants FAM, Meerpoel DEB and Keirse JNC. Br Med J 1998; 317: 502-5 2. Hull MGR. Managed care of infertility. Current Opinion in Obstetrics and Gynaecology 1996; 8:305-313 3. Glazener CMA, Kelly NJ, Weir MJA, David SE, Cornes JS and Hull MGR. The diagnosis of male infertility - prospective time-specific study of conception rates related to seminal analysis and post-coital sperm- mucus penetration and survival in otherwise unexplained infertility. Human Reproduction 1987; 8:665-671 4. Snick HKA, Snick TS, Evers JLH and Collins JA. The spontaneous pregnancy prognosis in untreated subfertile couples: the Walcheren primary care study. Human Reproduction 1997; 12:1582-1588 5. Hull MGR, Glazener CMA, Kelly NJ, Conway DI, Foster PA, Hinton RA, Coulson C, Lambert PA, Watt EM and Desai KM. Population study of causes, treatment, and outcome of infertility. Br Med J 1985;291:1693-7 |
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