Prophylactic antibiotics and endocervical microbial inoculation of the endometrium at embryo transfer.

Prophylactic antibiotics administered routinely to women at the time of oocyte retrieval were associated with a reduction in positive microbiology cultures of embryo catheter tips 48 h later in 78.4% of patients. The implantation and clinical pregnancy rates were significantly lower (9.3% vs 21.6%, p<0.001; 18.7% vs 41.3%, p<0.01) in the women with positive microbial catheter-tip cultures.