Cefuroxime is considered safe to use during pregnancy. The FDA classified it as Pregnancy Category B, meaning animal studies at doses up to 14 times the recommended human maximum showed no evidence of harm to the fetus, and no adequate controlled studies in pregnant women have identified a risk. It is one of the more commonly prescribed antibiotics for infections during pregnancy, suitable for use in all three trimesters.
What the Evidence Shows About Birth Defects
A prospective cohort study published in the British Journal of Clinical Pharmacology compared women who took cefuroxime in the first trimester to women who took other antibiotics known to be safe. The rate of major birth defects in the cefuroxime group was 3.2%, compared to 2% in the reference group. That difference was not statistically significant, meaning it fell within the range of normal variation. The two major malformations observed in the cefuroxime group (a heart defect and a genital anomaly) occurred at rates consistent with what you’d expect in the general population regardless of medication use.
Minor malformations were also comparable between groups: 10.7% in the cefuroxime group versus 6.2% in the reference group, again without a statistically meaningful difference. In short, first-trimester exposure does not appear to raise the risk of birth defects above the baseline rate.
Long-Term Child Development
A follow-up study tracked children born to 78 women who took cefuroxime during pregnancy, including 13 who were treated in the first trimester. Researchers monitored physical and mental development for at least 18 months after birth. None of the children showed any developmental abnormalities that could be linked to the medication. This study provides some of the most direct reassurance that the drug doesn’t affect a child’s growth or cognitive milestones after birth.
Why It’s Commonly Prescribed in Pregnancy
Cefuroxime is a second-generation cephalosporin, part of the same broad family as penicillin-type antibiotics. It’s used to treat urinary tract infections, respiratory infections, skin infections, and Lyme disease, all of which can occur during pregnancy and need treatment to protect both the mother and baby.
For urinary tract infections specifically, international guidelines list cefuroxime as appropriate throughout pregnancy and breastfeeding. Several national guidelines recommend it as either a first-line or second-line option for bladder infections and kidney infections in pregnant patients. It’s also a useful alternative if you have a mild penicillin allergy, since most people who react to penicillin can still tolerate cephalosporins safely.
How Pregnancy Affects the Drug
Your body processes cefuroxime differently when you’re pregnant. Blood levels of the drug are significantly lower during pregnancy than after delivery, the drug clears from your system faster, and more of it is excreted through your kidneys. This happens because pregnancy increases blood volume and kidney filtration rate. The practical consequence is that your doctor may need to adjust timing or dosing to make sure the antibiotic works effectively. Cefuroxime does cross the placenta, which is expected for this class of antibiotics and is actually necessary when treating infections that could affect the baby.
Safety During Breastfeeding
If you’re taking cefuroxime after delivery or while nursing, the drug passes into breast milk at low levels. After a standard dose, milk concentrations peak at roughly 0.37 to 1.45 mg/L depending on the route and timing. These amounts are not expected to cause serious problems for a breastfed infant. In a controlled study comparing nursing mothers on cefuroxime to those on another common cephalosporin, only about 2.6% of infants exposed through breast milk experienced any side effects at all, and these were limited to minor, self-resolving issues like a single case of diarrhea. No mothers needed to stop breastfeeding because of the medication.
One thing worth knowing: cefuroxime used alone does not appear to disrupt the healthy bacteria in breast milk itself, though it can temporarily alter an infant’s gut bacteria. Occasional loose stools or mild thrush in the baby are theoretically possible with any cephalosporin but haven’t been well documented with cefuroxime specifically.
How It Compares to Other Options
Cefuroxime sits alongside amoxicillin and amoxicillin-clavulanate as one of the commonly used beta-lactam antibiotics in pregnancy. All share the same FDA Pregnancy Category B designation. The choice between them typically comes down to what type of infection you have and which bacteria are likely causing it, rather than safety differences. Cefuroxime covers a broader range of bacteria than plain amoxicillin, which makes it useful when your doctor suspects a resistant organism or needs a wider safety net. For nursing mothers specifically, studies comparing cefuroxime to other cephalosporins found no significant difference in infant side effects, and all reported effects were minor.