May 22 2022

Classification of the active ingredient secnidazole

Risk level in pregnancy: This medicine is classified as Category C.

There are no controlled, systematic studies on the influence of secnidazole in pregnancy, so it should not be used in pregnant women, especially during the first trimester.

But it has at least two studies on the influence of secnidazole in pregnant women. In the first case, in 134 pregnant patients with bacterial vaginosis, treatment with nitroimidazole derivatives had a positive impact in reducing certain birth complications, such as premature rupture of the amniotic membrane, premature labor, maternal morbidity and mortality and low birth weight.

These complications were significantly less frequent in patients treated with secnidazole and other nitroimidazole derivatives that which were not treated[1] [2].

Another study in 200 patients suffering from parasites Entamoeba histolytica and treated with teclozan and secnidazole no recorded any defects in newborns [3].


1: Cotch MF, Pastorek JG 2nd, Nugent RP, Hillier SL, Gibbs RS, Martin DH, Eschenbach DA, Edelman R, Carey JC, Regan JA, Krohn MA, Klebanoff MA, Rao AV, Rhoads GG. Trichomonas vaginalis associated with low birth weight and preterm delivery. The Vaginal Infections and Prematurity Study Group. Sex Transm Dis. 1997 Jul;24(6):353-60.
2: Camargo RP, Simoes JA, Cecatti JG, Alves VM, Faro S. Impact of treatment for bacterial vaginosis on prematurity among Brazilian pregnant women: a retrospective cohort study. Sao Paulo Med J. 2005 May 2;123(3):108-12.
3: Mendiet P, Ávila D. Entamoeba Histolytica durante el embarazo: Patogenia y tratamiento. Medicina(Guayaquil): 6(4):260-262,2000

Update 17.06.2010

Meaning of category C

Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.