Pregnancy complications such as preterm labor and delivery, amniotic fluid infections, and low birth rate in infants have been correlated with T. vaginalis infection. According to the Vaginal Infections and Prematurity Study, pregnant woman with T. vaginalis had a 30% higher risk of delivering an infant preterm or with low birth weight. There was a 40% increased risk of both preterm and low birth weight, and twice the risk of stillbirth or neonatal death.1
Minkoff (1984) identified a strong association between T. vaginalis infection and premature rupture of membranes. Out of 233 patients studied, 27.5% of women with trichomoniasis demonstrated this complication whereas only 12.8% of women without trichomoniasis had this experience.2
Data on whether treatment of T. vaginalis in pregnancy can reduce adverse outcomes are conflicting. A recent metronidazole treatment trial of asymptomatic trichomoniasis in pregnant women did not prevent preterm delivery, and its authors concluded that "its use is not recommended in asymptomatic patients." This study raises questions regarding the need to screen for trichomoniasis during pregnancy in an asymptomatic population.3 This trial used a very high dose of metronidazole for treatment (8g total dose vs. 2g standard dose) and there was a delay between diagnosis of infection and administering treatment, so these two factors may have confounded the results.
- Cotch MF, Pastorek JG 2nd, Nugent RP, Yerg DE, Martin DH, Eschenbach DA. Demographic and behavioral predictors of Trichomonas vaginalis infection among pregnant women. The Vaginal Infections and Prematurity Study Group. Obstet Gynecol. 1991 Dec;78(6):1087-92.
- Minkoff H, Grunebaum AN, Schwarz RH, Feldman J, Cummings M, Crombleholme W, Clark L, Pringle G, McCormack WM. Risk factors for prematurity and premature rupture of membranes: a prospective study of the vaginal flora in pregnancy. Am J Obstet Gynecol. 1984 Dec 15;150(8):965-72.
- Klebanoff MA, Carey JC, Hauth JC, Hillier SL, Nugent RP, Thom EA, Ernest JM, Heine RP, Wapner RJ, Trout W, Moawad A, Leveno KJ, Miodovnik M, Sibai BM, Van Dorsten JP, Dombrowski MP, O'Sullivan MJ, Varner M, Langer O, McNellis D, Roberts JM; National Institute of Child Health and Human Development Network of Maternal-Fetal Medicine Units. Failure of metronidazole to prevent preterm delivery among pregnant women with asymptomatic Trichomonas vaginalis infection. N Engl J Med. 2001 Aug 16;345(7):487-93.
