Which factors are important for successful embryo transfer after in-vitro fertilization?

M.A. Stafford-Bell

Canberra Fertility Centre, 13 Napier Close, Deakin, A.C.T., 2600, Australia

Dear Sir,

I was interested to read the paper by Kovacs et al. following his questionnaire to IVF Units in Australia (Kovacs et al., 1999Go). The factor scoring the most marks, removal of hydrosalpinges before treatment, has undergone a considerable review among clinicians since that questionnaire and treatment is now I suspect determined firstly by whether a dilated tube is a true hydrosalpinx, i.e. whether it contains fluid and probably also by whether or not it communicates with the uterine cavity.

I was interested in the tenth of the 12 priorities, namely a dummy transfer before treatment. We introduced dummy transfer in April 1986, timing this for the cycle before treatment and attempting to carry out the procedure 2 days after ovulation was detected. We now transfer, on day 3, embryos which have demonstrated ongoing division and the day of dummy transfer has been modified accordingly. Any argument there may have been that this involves extra intervention for the patient has been negated by the use of the long down-regulation protocol which commences 1 week after detected ovulation in the cycle before treatment.

While an easy dummy run transfer is usually (but not invariably) correlated with an easy embryo transfer, there has been a very positive correlation between a difficult dummy run and a difficult, or very difficult, embryo transfer. We originally assigned those patients to dilation of the cervix at the time of the egg collection procedure but it is difficult to do this without producing hysteroscopically demonstrable endometrial trauma even if confined to the lower segment. It is unknown whether this trauma has any effect on implantation or whether there is healing in the 2 or 3 days prior to embryo transfer. We quickly instituted a policy of giving these patients Valium 5 mg orally ~40 min prior to embryo transfer and have had no major difficulties with embryo transfer in those patients. I acknowledge that this has not been subjected to a randomized controlled trial and I agree with Kovacs that such a trial is required. It is our clear impression that this treatment is beneficial.

A rather more difficult situation to assess is the rare patient in whom it is impossible to negotiate even the cervical canal with the catheter much less the internal os. We feel Valium is beneficial to some of those patients but not for others to the extent that if it is impossible to negotiate the cervical canal with the catheter we still allocate those patients to cervical dilation at the time of the egg collection procedure. Since they represent a very small group we have no data as to whether there is any difference in pregnancy rate for those few patients.

The above findings have been confirmed with every type of embryo transfer catheter that we have used over the years.

References

Kovacs, G.T. (1999) What factors are important for successful embryo transfer after in-vitro fertilization. Hum. Reprod., 14, 590–592.[Free Full Text]