University of Bristol, Division of Obstetrics and Gynaecology, St Michael's Hospital, Southwell Street, Bristol BS2 8EG, UK e-mail: d.j.cahill@bris.ac.uk
Dear Sir,
Thank you for the opportunity to respond to Dr Checks letter. One of the expectations of writing these Debate articles is that some response will be elicited. In his letter Dr Check makes a number of points.
One point relates to the role of laparoscopic ablation of endometriosis. The evidence for decision making is often challenging and this area is no exception. Until the Canadian study (Marcoux et al., 1997) was published, there were no prospective randomized controlled trials to examine this issue. Even that study has some flaws as I mentioned in my paper (Cahill, 2002
), one being that the ablative procedure was not the only treatment to which the subjects were exposed. Dr Check questions the role of ablative therapy based on unpublished data examining pregnancy and implantation rates. These data are difficult to interpret as they represent pregnancy rates, which are a factor of the implantation of several embryos. Only the implantation rates are useful as a marker of the quality of the oocytes fertilized, and levels of significance are not given. My own belief is that if laparoscopy is being undertaken as part of the normal investigative process for subfertility in my unit, I would want to undertake ablative therapy if endometrosis were present at that examination.
Dr Check makes a further comment on the role of day 3 FSH levels. It is a very reasonable hypothesis that early follicular phase events influence and may even dictate what happens later in the cycle. He asks whether higher FSH levels might explain the differences seen in follicular fluid endocrinology. They may well do but I have no evidence to support this. This is obviously an area of potential further study.
I thank Dr Check for his kind words and his interest in this paper.
References
Cahill, D.J. (2002) What is the optimal medical management of infertility and endometriosis? Hum. Reprod., 17, 11351140.
Marcoux, S., Maheux, R. and Berube, S. (1997) Laparoscopic surgery in infertile women with minimal or mild endometriosis. N. Engl. J. Med., 337, 217222.