Early pregnancy loss in women stimulated with gonadotropin-releasing hormone antagonist protocols according to oral contraceptive pill pretreatment

ObjectiveTo evaluate and compare the risk of early pregnancy loss in patients stimulated with GnRH antagonist protocols according to oral contraceptive pill (OCP) pretreatment.DesignRetrospective case–control study.SettingInstituto Valenciano de Infertilidad. University of Valencia. Spain.Patient(s)One thousand five hundred thirty-nine patients, aged <36, stimulated with GnRH antagonists for IVF between January 1, 2000 and November 1, 2005.Intervention(s)Reproductive outcome was compared based on the application (or not) of OCP pretreatment: 944 women were included in the OCP group and 595 in the non-OCP group. The Student’s t test was used for statistics.Main Outcome Measure(s)Pregnancy, biochemical pregnancy, ectopic pregnancy, early clinical pregnancy loss, early pregnancy loss, and ongoing pregnancy rates.Result(s)No significant differences were observed in any of the outcome parameters. Early pregnancy loss rates were similar: 23% in the OCP pretreatment group versus 19.2% in the non-OCP pretreatment group. However, longer periods of ovarian stimulation and higher doses of gonadotropins needed to be employed in the OCP group.Conclusion(s)There is not sufficient evidence to confirm OCP pretreatment as a risk factor for miscarriage in patients stimulated with GnRH antagonist protocols.