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N Engl J Med. 2019 Mar 14;380(11):1012-1021. doi: 10.1056/NEJMoa1808817.

A Randomized Trial of Prophylactic Antibiotics for Miscarriage Surgery.

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From the Institutes of Metabolism and Systems Research (D.L., A. Coomarasamy) and Applied Health Research (A. Wilson, C.A.H., L.M., J.R.B.B.) and the Health Economics Unit (T.R., I.G.), University of Birmingham, Birmingham, the Faculty of Medicine and Health Sciences, University of Nottingham, Nottingham (J. Daniels), Population Health Sciences, University of Bristol, Bristol (A. Merriel), the Institute of Translational Medicine, University of Liverpool (A. Weeks), and the Liverpool School of Tropical Medicine and Malawi-Liverpool-Wellcome Trust Clinical Research Programme (S.B.-Z., N.D.), Liverpool, and the Department of Obstetrics and Gynaecology, St. George's University of London, London (S.A.) - all in the United Kingdom; the Department of Obstetrics and Gynaecology, College of Medicine, Blantyre (C. Mhango, R.M., F.T., T.N., A. Chirwa, C. Mphasa, T.T.), and Kamuzu Central Hospital, Lilongwe (G.C., C. Mwalwanda, A. Mboma) - both in Malawi; the Aga Khan University Hospital and Medical College Foundation, Karachi, Pakistan (R.Q., I.A., H.I.); Special Program of Research, Development, and Research Training in Human Reproduction, Department of Reproductive Health and Research, World Health Organization, Geneva (O.T.O., A.M.G.); Ifakara Health Institute, Dar es Salaam, Tanzania (G.M., J.C., G.W., B.S.); Sanyu Africa Research Institute and Mbale Regional Referral Hospital, Mbale (J. Ditai, C.O.T., J.A.), and Soroti Regional Referral Hospital, Soroti (J.E., H.U., M.I., J.J.M.) - all in Uganda; Clinical Biostatistics Unit, Hospital Universitario Ramón y Cajal, Centro de Investigación Biomédica en Red en Epidemiología y Salud Pública and Instituto de Investigación Sanitaria, Madrid (J.Z.); and the Research Centre for Global Child Health, the Hospital for Sick Children, Toronto (Z.A.B.).



Surgical intervention is needed in some cases of spontaneous abortion to remove retained products of conception. Antibiotic prophylaxis may reduce the risk of pelvic infection, which is an important complication of this surgery, particularly in low-resource countries.


We conducted a double-blind, placebo-controlled, randomized trial investigating whether antibiotic prophylaxis before surgery to complete a spontaneous abortion would reduce pelvic infection among women and adolescents in low-resource countries. We randomly assigned patients to a single preoperative dose of 400 mg of oral doxycycline and 400 mg of oral metronidazole or identical placebos. The primary outcome was pelvic infection within 14 days after surgery. Pelvic infection was defined by the presence of two or more of four clinical features (purulent vaginal discharge, pyrexia, uterine tenderness, and leukocytosis) or by the presence of one of these features and the clinically identified need to administer antibiotics. The definition of pelvic infection was changed before the unblinding of the data; the original strict definition was two or more of the clinical features, without reference to the administration of antibiotics.


We enrolled 3412 patients in Malawi, Pakistan, Tanzania, and Uganda. A total of 1705 patients were assigned to receive antibiotics and 1707 to receive placebo. The risk of pelvic infection was 4.1% (68 of 1676 pregnancies) in the antibiotics group and 5.3% (90 of 1684 pregnancies) in the placebo group (risk ratio, 0.77; 95% confidence interval [CI], 0.56 to 1.04; P = 0.09). Pelvic infection according to original strict criteria was diagnosed in 1.5% (26 of 1700 pregnancies) and 2.6% (44 of 1704 pregnancies), respectively (risk ratio, 0.60; 95% CI, 0.37 to 0.96). There were no significant between-group differences in adverse events.


Antibiotic prophylaxis before miscarriage surgery did not result in a significantly lower risk of pelvic infection, as defined by pragmatic broad criteria, than placebo. (Funded by the Medical Research Council and others; AIMS Current Controlled Trials number, ISRCTN97143849.).

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