A kit having instructions for use for performing uterine lavage in a female patient includes a uterine lavage catheter configured for insertion into a woman's uterus to remove viable blastocysts from the uterus, and one or more first containers having a sufficient dosage amount of a GnRH antagonist to cause desynchronization of the endometrium of the patient prior to, during and/or following recovery of viable blastocysts from the uterus.