A randomized clinical trial of prophylaxis for vacuum abortion: 3 versus 7 days of doxycycline

To estimate prospectively whether reducing oral doxycycline prophylaxis from 7 to 3 days increases the incidence of endometritis after elective first-trimester vacuum abortion.

We randomized 800 women requesting first-trimester abortion to two study groups: 1) 100 mg of doxycycline administered orally twice a day for 7 days or 2) 100 mg of doxycycline orally twice a day for 3 days followed by an oral placebo twice daily for the last 4 days. Doxycycline was prescribed immediately after surgery.

There were no statistically significant differences in age, race, gravidity, parity, number of previous abortions, current gestational age, and history of previous pelvic infection, chlamydia, or intrauterine device use. Women in the doxycycline plus placebo group were more likely to have had a history of gonorrhea (3.3% versus 0.8%, P =.42) or chlamydia (7.0% versus 4.3%, P =.18). The 66.3% of enrollees returning for 2-week examinations were distributed similarly between study groups and were similarly compliant in self-reported pill taking (mean 97.5%). The study groups did not differ in the incidence of postoperative symptoms or examination findings suggesting infection. One patient in the doxycycline-only group developed endometritis and was treated as an outpatient.

Shortening oral doxycycline prophylaxis from 7 to 3 days had no adverse effect on the incidence of postabortion infection.