Increasing levels of estradiol are deleterious to embryonic implantation because they directly affect the embryo

OBJECTIVE

To investigate whether the deleterious effect of E(2) on embryonic implantation is due to a direct effect on the endometrium, on the embryo, or both.

DESIGN

Prospective, controlled in vitro study.

SETTING

Tertiary infertility center.

PATIENT(S)

Fertile patients in the luteal phase with histologically normal endometrium who were attending the infertility clinic as oocyte donors (n = 14).

INTERVENTION(S)

E(2) dose-response (0, 10(-8), 10(-7), 10(-6), 10(-5), and 10(-4) M) and time course (day 2 vs. day 5) experiments were performed in an in vitro embryo adhesion assay composed of human polarized endometrial epithelial cells obtained from fertile patients and mouse embryos.

MAIN OUTCOME MEASURE(S)

Blastocyst formation rate and embryo adhesion rate.

RESULTS

Monolayers of polarized endometrial epithelial cells expressed ERalpha at the mRNA level. The E(2) dose response of blastocysts with polarized endometrial epithelial cells (n = 235) demonstrated a progressive reduction in embryonic adhesion that was statistically significant at 10(-6) M. When polarized endometrial epithelial cells were treated alone with increasing doses of E(2) for 3 days and E(2) was then removed and blastocysts added (n = 410), embryonic adhesion was not significantly reduced, except at 10(-4) M. When 2-day mouse embryos (n = 609) were treated with increasing E(2) concentrations until day 5, the rate of blastocyst formation significantly decreased at a concentration >or= 10(-6) M, and embryonic adhesion decreased when blastocysts (n = 400) were obtained at a concentration >or= 10(-7) M. Time course experiments of embryos cultured for 2 days with polarized endometrial epithelial cells (n = 426) showed that the adhesion rate was higher at E(2) levels of 10(-7), 10(-6) and 10(-5) M compared with embryos cultured for 5 days (n = 495).

CONCLUSION(S)

High E(2) levels are deleterious to embryo adhesion in vitro, mainly because they have a direct toxic effect on the embryo that may occur at the cleavage stage.

Use of intrauterine contraceptive devices in nulliparous women: personal experience over a 12-year period

OBJECTIVE

To evaluate the use of intrauterine contraceptive devices (IUDs) in nulliparous women compared to their use in parous women.

METHODS

A comparative cross-sectional study was carried out to determine the reasons for removal of IUDs inserted between 1985 and 1996 in a sample of 227 nulliparous women and 2080 parous women. The statistical analysis was performed using the chi 2 test; the differences were considered to be significant when p < 0.05.

RESULTS

The reasons for removal of IUDs in the two groups were: expiry, 49.1% in the nulliparous group vs. 48.2% in the parous group; planned pregnancy, 21.7% vs. 15.4%; accidental pregnancy, 4.8% vs. 6.3%; expulsion, 1.6% vs. 5.1%; pelvic inflammatory disease, 1.6% vs. 1.1%; pain and/or bleeding, 14.5% vs. 10.2%; other, 6.4% vs. 6.3%; vasectomy or tubal sterilization, 0% vs. 7%.

CONCLUSION

Our data suggest that nulliparity is not a contraindication for the use of an IUD, and that the use of an IUD in nulliparous women is as safe and effective as in parous women.