Relationship between serum estrogen concentration and propofol consumption: A prospective observational study of patients undergoing oocyte retrieval.

AIM: Controlled ovarian hyperstimulation results in elevated levels of estrogen during in vitro fertilization (IVF). Although serum ovarian steroid hormones were found to influence central nervous system and anesthetic requirements, the relationship between propofol requirements and serum estrogen concentration in women undergoing oocyte retrieval has not been studied. The aim of this study was to determine the relationship between serum estrogen and progesterone concentrations and the required propofol dose for loss of consciousness (LOC).

METHODS: Ninety patients undergoing oocyte retrieval for IVF were enrolled. Anesthesia was induced by administration of 200 mL/h propofol (1%) infusion to reach LOC. Anesthesia was maintained with a propofol infusion guided by entropy. The correlation between estrogen, progesterone levels and propofol dose at the time of LOC was analyzed. Emergence time from anesthesia and total propofol consumption were recorded.

RESULTS: The mean serum estradiol concentration was 1825 ±1135 pg/mL. There was a significant positive correlation between serum estradiol and propofol dose required for LOC (Pearson's correlation r = 0.28, P = 0.008). Progesterone had no significant correlation with total propofol dose at the time of LOC. Patients with high estradiol levels (higher than the median value) had similar propofol requirement for LOC, total propofol consumption and emergence time with patients who had low (below the median value) levels.

CONCLUSION: Although increased estrogen levels create a positive correlation with propofol dose for LOC, estrogen does not seem to be the only factor for anesthetic requirement of patients undergoing controlled ovarian hyperstimulation.