Confounding variables affectingin vitro fertilization success: A decade of experience
To evaluate etiology of infertility, female age, ovarian response and stimulation protocol in affecting in vitro fertilization (IVF) success.
Retrospective analysis was used. Computer records of all 5209 cycles initiated in 2391 couples from February 1, 1984 to December 31, 1993 were analyzed.
There were 644 intrauterine, 24 solely ectopic and 7 heterotopic pregnancies. Pregnancy rates increased with number of embryos transferred with a significant increase still found between transfer of three or four embryos. Multiple gestations also increased in association with an increasing number of embryos transferred. Pregnancy rates per cycle did not decline with repeated cycles. Reduced pregnancy rates were associated with a primary diagnosis of male infertility. Covariates associated with a better pregnancy rate were younger age of the female partner or higher peak preovulatory serum estradiol. Routine administration of GnRH-agonist was associated with a reduced cycle cancellation rate, an increase in oocytes retrieved and an improved pregnancy rate.
Couples with male infertility and increased female age should be counselled regarding the reduced prognosis for success.
Key wordsconfounding variables in vitro fertilization pregnancy
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