Endocrine and clinical effects of micronized estradiol administered vaginally or orally.

OBJECTIVE

To determine the impact of the vaginal route of micronized estradiol (E(2)) administration upon hepatic globulin and lipid production and upon the outcome of oocyte donation cycles in which the recipients received E(2) via this route.

DESIGN

Series report.

SETTING

University-based assisted reproduction techniques (ART) program.

PATIENT(S)

Recipients of donor oocytes.

INTERVENTION(S)

Administration of micronized E(2) via the oral or vaginal route, oocyte donation, and embryo transfer.

MAIN OUTCOME MEASURE(S)

Measurements of the serum levels of free E(2), sex hormone-binding globulin (SHBG), total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), very-low-density lipoprotein (VLDL), as well as endometrial thickness and pregnancy outcome.

RESULT(S)

Serum SHBG and lipoprotein levels were unaltered by the vaginal as compared with the oral route of E(2) administration. Serum free E(2) levels were significantly higher after vaginal administration. Ten patients who had previously failed to achieve adequate endometrial thickness with an oral regimen were found to have adequate endometrial thickness after vaginal E(2) administration and seven of them achieved an ongoing pregnancy after embryo transfer.

CONCLUSION(S)

Vaginal administration of micronized E(2) results in significantly higher free serum E(2) levels when compared to levels achieved after oral E(2) administration. Hepatic globulin and lipoprotein production is similar despite 10-fold higher serum E(2) levels after the vaginal administration. The greater efficiency of E(2) delivery to the endometrium after vaginal administration makes this route a good option for patients who fail to achieve adequate endometrial thickness with oral E(2) administration.