Co-Amoxiclav Pregnancy Category
Co-amoxiclav (amoxicillin/clavulanate) is classified as FDA Pregnancy Category B, indicating that animal reproduction studies have failed to demonstrate fetal risk and there are no adequate well-controlled studies in pregnant women. 1, 2
FDA Classification and Safety Profile
The FDA drug label explicitly states that reproduction studies in pregnant rats and mice at doses up to 1,200 mg/kg/day revealed no evidence of harm to the fetus due to amoxicillin and clavulanate potassium. 1
Amoxicillin alone is also classified as FDA Pregnancy Category B, with reproduction studies in mice and rats at doses up to 2000 mg/kg showing no evidence of harm to the fetus. 2
The European Respiratory Society/Thoracic Society of Australia and New Zealand (ERS/TSANZ) guidelines classify amoxicillin as Category A (compatible with all trimesters) and amoxicillin/clavulanic acid as Category B1 (compatible with pregnancy). 3, 4
Clinical Evidence and Recommendations
Human data indicate that cephalosporins and penicillins, including amoxicillin, are not teratogenic at usual therapeutic doses, making them preferred first-line agents during pregnancy. 3, 4
The European Society of Cardiology explicitly lists amoxicillin among antibiotics that can be given during all trimesters of pregnancy, classified as FDA group B. 5
The CDC recommends amoxicillin for multiple indications in pregnant women, including anthrax post-exposure prophylaxis, Chlamydia trachomatis infection, and Salmonella gastroenteritis. 5
Important Clinical Caveat
Amoxicillin/clavulanic acid should NOT be used in women at risk of preterm delivery due to a very low risk of necrotizing enterocolitis in neonates. 3, 4, 1
The FDA drug label specifically notes that in a single study of women with premature rupture of fetal membranes, prophylactic treatment with amoxicillin/clavulanate potassium may be associated with an increased risk of necrotizing enterocolitis in neonates. 1
In this specific scenario, amoxicillin alone (without clavulanate) should be considered as an alternative. 4
Understanding the Category B Classification
Category B means that either animal reproduction studies have not demonstrated fetal risk but there are no controlled studies in pregnant women, OR animal studies showed adverse effects that were not confirmed in controlled studies in women. 3, 6
For co-amoxiclav, the classification is based on animal studies showing no harm, but with the caveat that "animal reproduction studies are not always predictive of human response." 1, 2
The drug should be used during pregnancy "only if clearly needed," which is standard language for Category B medications. 1, 2
Breastfeeding Considerations
Ampicillin-class antibiotics, including amoxicillin/clavulanate, are excreted in breast milk, and caution should be exercised when administered to nursing women. 1, 2
The ERS/TSANZ guidelines classify amoxicillin/clavulanic acid as "compatible" with breastfeeding, representing the highest safety designation for antibiotics during lactation. 3, 7