From the Guidelines
Macrobid (Nitrofurantoin) is safe to use during pregnancy.
Evidence Summary
- The Infectious Diseases Society of America guidelines support the use of nitrofurantoin in pregnant women with asymptomatic bacteriuria, as it decreases the risk of pyelonephritis and low-birth-weight infants 1.
- A prospective, controlled trial randomized bacteriuric women to receive a 1-week course of therapy with nitrofurantoin, demonstrating its effectiveness in preventing adverse outcomes 1.
- A Cochrane review found that 7 days of nitrofurantoin therapy was more effective than a single dose in preventing lower birth weight, although no differences in pyelonephritis or preterm delivery were observed between the 2 study arms 1.
- Nitrofurantoin is preferred due to its safety in pregnant women, although it may be less effective as short-course therapy for treatment of acute cystitis in women 1.
Key Points
- Nitrofurantoin dosage: typically a 4- to 7-day course of therapy, although the optimal duration may be antimicrobial-specific 1.
- Safety: nitrofurantoin is considered safe for use in pregnant women, with a low risk of adverse effects 1.
- Benefits: treatment of asymptomatic bacteriuria with nitrofurantoin decreases the risk of pyelonephritis, low-birth-weight infants, and preterm delivery 1.
From the Research
Safety of Macrobid (Nitrofurantoin) during Pregnancy
- The safety of Macrobid (Nitrofurantoin) during pregnancy has been evaluated in several studies, with varying results 2, 3, 4, 5, 6.
- A retrospective analysis of 91 pregnancies found no evidence that nitrofurantoin macrocrystals were toxic to the fetus or unsafe for treatment of maternal urinary tract infection during pregnancy 2.
- A systematic review and meta-analysis of 8 studies found that exposure to nitrofurantoin during early pregnancy was not associated with an increased risk of major malformations in cohort studies, but a slight increase in risk was found in case-control studies 3.
- Another study found that postcoital prophylaxis with nitrofurantoin macrocrystals was effective in preventing recurrent urinary tract infections during pregnancy 4.
- A review of the risks of antibacterial agents in pregnancy found that nitrofurantoin is a valid option in pregnancy, except in the latter stages, due to the risk of hemolytic anemia in the newborn 5, 6.
- A case report described a newborn who developed hemolytic anemia after maternal treatment with nitrofurantoin at the end of pregnancy, highlighting the potential risks of using this medication during this time 6.
Potential Risks and Considerations
- The use of nitrofurantoin during pregnancy may be associated with an increased risk of certain malformations, such as hypoplastic left heart syndrome 3.
- The medication may also pose a risk of hemolytic anemia in the newborn, particularly if used during the latter stages of pregnancy 5, 6.
- As with any medication, the potential benefits and risks of using nitrofurantoin during pregnancy must be carefully considered, and alternative treatments may be recommended in some cases 5.