Your San Diego fertility center: Reproductive Sciences Center & Genetics Institute

where babies come from...

Response To Controlled Ovarian Hyperstimulation (COH), As Measured By Peak Estradiol Levels And Number Of Follicles, Does Not Correlate With Singleton Birth Weight In Oocyte Donation Cycles.

This research presented at the American Society for Reproductive Medicine (ASRM), Montreal, 2005.

CA Adams, LS Anderson and SH Wood. Reproductive Sciences Center, La Jolla, CA, USA.

Objective: Several studies have reported that singleton birth weights after IVF are decreased compared to spontaneous conception. It has been suggested that this association may be due to the supraphysiologic hormonal environment present in these cycles, a hypothesis supported by data indicating a negative correlation between estradiol production and birth weight in IVF-ET cycles. Whether this is related to an effect of elevated ovarian hormonal production on the intrauterine environment or on the oocytes produced is unclear. To examine this question, we studied IVF cycles in which these possible effects are uncoupled: oocyte donation cycles. In particular, we examined whether there is an association between response to controlled ovarian hyperstimulation (COH) and birth weight in oocyte donation cycles, cycles in which embryos are transferred into a unstimulated uterine environment.

Design: A retrospective analysis of 100 consecutive viable singleton births resulting from oocyte donation in a private IVF clinic.

Materials and Methods: Birth weights and gestational age at delivery were evaluated for singleton deliveries from fresh and frozen oocyte donation cycles. Oocyte donors (mean age: 25.0 ± 4.2) underwent ovarian stimulation a standard protocol using FSH and FSH/LH containing gonadotropins following down regulation with leuprolide acetate. Correlations were calculated between peak estradiol levels, number of days of stimulation, number of follicles aspirated, and number of oocytes retrieved, and obstetrical outcome.

Results: There was no correlation between the peak estradiol level (mean: 2742 pg/ml ± 1266; range 511 to 8955 pg/ml) or day of HCG (mean 9.9 ± 1.0) with birth weight (mean: 3421.3 ± 594.2) or gestational age (mean: 38.5 ± 2.3). In addition, neither the number of follicles aspirated (mean: 16.81 ± 7.2) nor the number of oocytes retrieved (mean: 14.3 ± 6.9) correlated with birth weight or gestational age. Possible confounding variables, recipient age and BMI, were not significantly associated with birth weight or gestational age..

Conclusions: No correlation was found between ovarian response to COH by young oocyte donors, as measured by peak estradiol, number of days of stimulation and number of follicles, with birth weight of singleton infants. From this data it appears that any adverse effect of supraphysiologic estradiol production and multiple follicular development in IVF results from an effect on the intrauterine environment rather than an effect on the oocyte/embryo.