Is it safe to take D-mannose (a sugar supplement) during pregnancy?

Safety of D-Mannose During Pregnancy

Based on current evidence, D-mannose cannot be recommended during pregnancy due to insufficient safety data and the lack of established guidelines addressing its use in pregnant women.

Current Guidelines on Medications During Pregnancy

The American Diabetes Association's Standards of Medical Care in Diabetes (2020) emphasizes that insulin is the preferred agent for managing diabetes during pregnancy 1. While this doesn't directly address D-mannose, it highlights the cautious approach to medication use during pregnancy, with a strong preference for medications with established safety profiles.

When considering any supplement during pregnancy, healthcare providers should follow these principles:

• Medications and supplements without established safety data should be avoided during pregnancy
• The risk-benefit ratio must strongly favor the mother and fetus
• Only interventions with proven safety records should be recommended

What is D-Mannose?

D-mannose is a simple sugar (monosaccharide) that is:

• Used primarily for prevention of recurrent urinary tract infections (UTIs)
• Believed to work by preventing bacterial adhesion to the urinary tract epithelium
• Available as an over-the-counter supplement in various forms (powder, capsules)

Evidence on D-Mannose for UTIs

While some evidence suggests D-mannose may help prevent recurrent UTIs in non-pregnant women:

• The most recent high-quality randomized controlled trial (2024) found that daily D-mannose did not reduce the proportion of women experiencing subsequent UTIs compared to placebo 2
• A 2022 Cochrane review concluded there is "currently little to no evidence to support or refute the use of D-mannose to prevent or treat UTIs in any population" 3
• Earlier smaller studies showed some potential benefit but had significant methodological limitations 4, 5

Specific Concerns for Pregnancy

Several key concerns exist regarding D-mannose use during pregnancy:

1. Lack of pregnancy-specific safety data: No clinical trials have specifically evaluated D-mannose safety during pregnancy
2. Unknown placental transfer: It's unclear how much D-mannose crosses the placenta and what effects it might have on fetal development
3. Potential metabolic effects: As a sugar, D-mannose could theoretically affect glucose metabolism, which is already altered during pregnancy

Management of UTIs During Pregnancy

For pregnant women with UTIs or at risk of recurrent UTIs:

1. First-line approach: Consult with an obstetrician for appropriate management
2. Established treatments: Several antibiotics have established safety profiles in pregnancy and are preferred for treating UTIs
3. Prevention strategies:
   • Adequate hydration
   • Proper hygiene practices
   • Urinating before and after intercourse
   • Avoiding irritating feminine products

Conclusion

Until specific safety data becomes available for D-mannose during pregnancy, pregnant women should:

• Avoid using D-mannose supplements
• Consult with their healthcare provider about evidence-based approaches to UTI prevention and treatment
• Use only medications and supplements with established safety profiles during pregnancy

If a pregnant woman is already taking D-mannose, she should inform her healthcare provider immediately to discuss appropriate alternatives.