The value of routine estradiol monitoring in assisted conception cycles.

Background: Traditional monitoring of an in vitro fertilization (IVF) treatment cycle includes regular estradiol levels and ultrasound scans in an attempt to reduce the risk of ovarian hyperstimulation syndrome (OHSS). The need for estradiol monitoring remains controversial.
Methods: We reviewed 538 consecutive cycles of IVF that were carried out in our unit to ascertain whether routine estradiol monitoring was of help in preventing OHSS and could be used to predict treatment outcome. Two hundred and sixty-eight patients had their ovarian response monitored with ultrasound (USS) and estradiol levels on the day of hCG administration. The following 270 had USS monitoring but only had an estradiol level checked if they were deemed to be at high risk of OHSS (> 20 follicles on USS or symptomatic).
Results: Pregnancy rates per treatment cycle and per embryo transfer were similar in the two groups (all p > 0.05). There were two patients in each group requiring admission to hospital for OHSS.
Conclusions: Estradiol levels did not correlate with IVF outcome. In summary therefore estradiol levels are a poor predictor of treatment success and done routinely do not reduce the incidence of OHSS. It is only necessary to measure the estradiol level in those patients at risk of OHSS on USS monitoring.