The effect of same-day pregnancy testing on the incidence of luteal phase pregnancy

To assess the impact of same-day pregnancy testing on the incidence of luteal phase pregnancy (pregnancy in which conception occurs before sterilization).

Retrospectively, all patients (N = 1006) undergoing laparoscopic tubal ligations at the Regional Medical Center, Memphis, from May 1990 through December 1991 were reviewed for sterilization failures. Negative urine pregnancy tests were documented on all scheduled patients at their preoperative examination. After the first 401 sterilizations, same-day pregnancy testing with enzyme-linked immunosorbent assay (ELISA) pregnancy tests was instituted. We reviewed the records of all presumed sterilization failures as well as all patients with a positive pregnancy test on the day of surgery. Last menstrual period, ultrasound records, and date of delivery were analyzed to determine time of conception.

Seven luteal phase pregnancies were discovered among the first 401 sterilization cases (17 per 1000). No luteal phase pregnancies occurred in the next 605 sterilizations after institution of same-day pregnancy testing. Eight patients' sterilizations were canceled because of a positive pregnancy test on the morning of surgery. If these patients had not been eliminated, the incidence of luteal phase pregnancies in this second group would have been 13 per 1000 sterilization procedures.

Same-day pregnancy testing with an ELISA-type pregnancy test is a rapid, inexpensive, and effective means of reducing the incidence of luteal phase pregnancy.