Treatment of Trichomoniasis in Pregnancy
Recommended Treatment Regimen
Pregnant women with trichomoniasis should be treated with metronidazole 2 g orally as a single dose after the first trimester. 1, 2
Critical Timing Considerations
Metronidazole is contraindicated during the first trimester of pregnancy due to concerns about fetal organogenesis, as the drug crosses the placental barrier rapidly and its effects on early fetal development are not fully known. 1, 2, 3
Treatment after the first trimester is warranted because trichomoniasis is associated with serious adverse pregnancy outcomes including premature rupture of membranes and preterm delivery. 1, 2, 4
First Trimester Management
If a pregnant woman presents with symptomatic trichomoniasis during the first trimester, treatment must be delayed until the second trimester begins. 1
The evidence does not support effective alternative therapies during the first trimester—topical preparations like clotrimazole have poor efficacy (approximately 50% cure rate) and are not recommended. 5, 6
Dosing Rationale in Pregnancy
The single 2 g dose is specifically recommended for pregnant women rather than the 7-day regimen to minimize total fetal drug exposure. 1, 2
This approach balances the need to treat the infection (preventing preterm birth) against minimizing medication exposure to the developing fetus. 1, 4
Partner Treatment is Mandatory
All sexual partners must be treated simultaneously with the same metronidazole regimen, regardless of symptoms, as most infected men are asymptomatic. 7, 8, 2
Patients must abstain from sexual intercourse until both partners complete treatment and are asymptomatic to prevent reinfection. 7, 8, 2
Failure to treat partners is the most common cause of treatment failure and reinfection. 8
Critical Patient Counseling
Patients must avoid all alcohol during treatment and for at least 24 hours after the last dose to prevent severe disulfiram-like reactions. 7, 8
Common side effects include nausea (23%), headache (7%), and vomiting (4%), but these are generally mild to moderate. 9
How Trichomoniasis is Contracted
Transmission Mechanism
Trichomoniasis is contracted through sexual contact with an infected partner. 1
Key Epidemiologic Features
Trichomonas vaginalis is a sexually transmitted protozoan that causes the most common non-viral sexually transmitted infection worldwide. 1, 4, 9
Most infected men are asymptomatic carriers, making them unknowing vectors of transmission to female partners. 1, 7
Among women, the majority develop symptoms including diffuse, malodorous yellow-green vaginal discharge with vulvar irritation, though some women have minimal symptoms. 1