Comment on ‘A multicentre randomized controlled trial of expectant management versus IVF in women with Fallopian tube patency’
Department of Obstetrics & Gynecology, McMaster University, EGH/tmh, L8N 325, Canada
Email: hughese{at}mcmaster.ca
Sir,
Thank you for the opportunity of responding to Dr Gnoth's comments on the EMVI Trial. As highlighted in our original manuscript, the comparison of first IVF cycle with three months of unprotected intercourse was pragmatic. Although a longer follow-up would have been desirable, it was not acceptable to patients. Faced with the potential of even 3 months of untreated observation rather than an immediate IVF treatment cycle, only one-third of eligible subjects agreed to enrol (Hughes et al., 2004
).
The study suggesting a conception rate of 54% following untreated observation was not particularly relevant to the EMVI sample (Snick et al., 1997). The mean age of EMVI subjects was 33 years and mean duration of subfertility 56 months (Hughes et al., 2004). Snick et al. (1997) followed younger women after only 12 months of unprotected intercourse, and not surprisingly, their spontaneous live-birth rate over the subsequent 24 months was 
50%. However, the probability of live birth did not significantly increase over the subsequent 12 months. In this and other studies, following 36 months of unprotected intercourse, it fell to 
1% per cycle (Collins et al., 1995).
The cited cumulative pregnancy rate of only 54% following up to five cycles of IVF may also be a poor comparator because this does not reflect current practice (Stolwijk et al., 2000). Based on treatment between 1991 and 1998, this fails to reflect the substantial gains made in IVF success over the last decade, with delivery per cycle in 2001 reaching 33% (National Summary and Fertility Clinic Report, 2004).
An important justification for the EMVI trial was the absence of valid data comparing current IVF outcomes with no treatment in couples with persistent subfertility and Fallopian tube patency. In this context, the study confirmed a marked difference in live-birth rate of only 1% per untreated cycle compared with 30% following a single IVF treatment cycle.
References
Collins JA, Burroow EA and Willan AR (1995) The prognosis for live birth among untreated infertile couples. Fertil Steril 64, 22–28.[Web of Science][Medline]
Hughes EG, Beecroft ML, Wilkie V, Burville L, Claman P, Tummon I, Greenblatt E, Fluker M and Thorpe K (2004) A multicentre randomized controlled trial of expectant management versus IVF in women with Fallopian tube patency. Hum Reprod 19, 1105–1109.
National Summary and Fertility Clinic Report (2004) Source: MMWR, April 30, 53(SS01), 1–20.
Snick HK, Snick TS, Evers JL and Collins JA (1997) The spontaneous pregnancy prognosis in untreated subfertile couples: the Walcheren primary care study. Hum Reprod 12, 1582–1588.
Stolwijk AM, Wetzels AM and Braat DD (2000) Cumulative probability of achieving an ongoing pregnancy after in-vitro fertilization and intracytoplasmic sperm injection according to a woman's age, subfertility diagnosis and primary or secondary subfertility. Hum Reprod 15, 203–209.
Submitted on June 22, 2004; accepted on July 2, 2004.
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