Can an active Trichomonas (trichomoniasis) infection cause problems for a neonate delivered vaginally?

Trichomonas Vaginalis Infection in Pregnancy and Neonatal Risks

Active trichomonas infection during pregnancy can potentially cause adverse outcomes for both the pregnancy and neonate, including increased risk of preterm birth and low birth weight, though direct transmission to neonates during vaginal delivery appears to be uncommon.

Maternal and Pregnancy Complications

• Trichomonas vaginalis infection during pregnancy has been associated with adverse pregnancy outcomes including premature rupture of membranes, preterm labor, and preterm delivery 1, 2
• Studies have demonstrated that pregnant women with T. vaginalis infection have approximately 30% increased risk of low birth weight (OR 1.3; 95% CI 1.1-1.5) and preterm delivery (OR 1.3; 95% CI 1.1-1.4) 3
• The attributable risk of T. vaginalis infection associated with low birth weight varies by race, with higher impact in Black women (11%) compared to Hispanic (1.6%) and White women (1.5%) 3

Neonatal Transmission and Outcomes

• There is limited evidence of direct neonatal infection from vaginal delivery through an infected birth canal 2
• While vertical transmission at birth is possible, documented cases of neonatal trichomonas infection are relatively rare 4
• When neonatal infection does occur, T. vaginalis has been found in the pharynx and lower respiratory tract of neonates with respiratory disease 4
• Some case reports have suggested a potential association between neonatal trichomonas infection and intellectual disability, though this connection requires further research 4

Treatment Considerations During Pregnancy

• The CDC recommends treating T. vaginalis infection with metronidazole 2g orally in a single dose or 500mg twice daily for 7 days 1, 2
• However, treatment during pregnancy presents a complex risk-benefit consideration:
  • Metronidazole is contraindicated during the first trimester of pregnancy 1, 2
  • Treatment can be administered after the first trimester with 2g metronidazole as a single dose 2
• Paradoxically, some studies suggest that treatment of asymptomatic trichomonas during pregnancy with metronidazole may potentially increase the risk of preterm birth 5, 6
• A randomized trial that treated asymptomatic trichomoniasis between 16-23 weeks was stopped early because metronidazole treatment was associated with increased preterm birth (RR 1.8; 95% CI 1.2-2.7) 6

Clinical Management Approach

• Screen symptomatic pregnant women for T. vaginalis infection 2
• For pregnant women with symptomatic infection:
  • Avoid treatment during first trimester 1, 2
  • After first trimester, treat with metronidazole 2g as a single dose 2
• Ensure partners are treated to prevent reinfection 2
• For asymptomatic pregnant women with T. vaginalis, carefully weigh risks and benefits of treatment given the paradoxical findings regarding preterm birth 5, 6
• Consider enhanced prenatal monitoring for women with untreated T. vaginalis infection due to the associated risks of preterm birth and low birth weight 3

Important Caveats

• The evidence regarding neonatal outcomes specifically from vaginal delivery through an infected birth canal is limited 2, 4
• The risk-benefit analysis of treatment during pregnancy remains complex, as some studies suggest treatment itself may increase certain risks 5, 6
• High-quality medical care during pregnancy may help reduce the incidence of trichomoniasis-related complications 7
• Patients allergic to metronidazole present a particular challenge, as alternative treatment options are limited 2, 4