Serum estradiol levels during controlled ovarian hyperstimulation influence the pregnancy outcome of in vitro fertilization in a concentration-dependent manner.

Objective: To determine an optimal serum E(2) level on the day of hCG administration in controlled ovarian hyperstimulation (COH) during IVF-ET without compromising pregnancy outcome.

Design: Retrospective study.

Setting: Large urban medical center.

Patient(s): Data of 455 cycles of fresh IVF-ET with COH.

Intervention(s): Serum E(2) levels on the day of hCG administration were categorized into five groups: group A (<1000 pg/mL), group B (1000-2000 pg/mL), group C (2000-3000 pg/mL), group D (3000-4000 pg/mL), and group E (>4000 pg/mL).

Main Outcome Measure(s): Serum E(2) levels, number of oocytes retrieved, pregnancy outcomes.

Result(s): Of 455 cycles, 148 (32.5%) cycles resulted in clinical pregnancy. The implantation rate was 12.2%, and the delivery rate was 18.7%. The number of oocytes obtained increased with increasing serum E(2) levels. The pregnancy rate gradually increased from group A to D as E(2) levels increased but decreased in group E. In women <38 years, the IVF-ET outcomes were similar to those of total patients. However, in women >/=38 years old, pregnancy and delivery rates were higher in group C than in other groups.

Conclusion(s): These results show that serum E(2) levels have a concentration-dependent effect on the pregnancy outcome, suggesting an optimal range of E(2) level for achieving a successful pregnancy. This optimal range of serum E(2) level in women is age dependent: 3000-4000 pg/mL for women <38 years and 2000-3000 pg/mL for women >/=38 years.