Co‑amoxiclav Use in Pregnancy and Lactation

Safety Classification and Regulatory Status

The European Respiratory Society (ERS) classifies co‑amoxiclav as compatible throughout all trimesters (TGA Category B1, FDA Category B), based on studies that have not demonstrated an increased risk of fetal abnormalities【1】【2】【3】【4】.

ERS guidelines state that the risk of oral clefts associated with first‑trimester exposure is very low, and cohort studies have not confirmed a significant increase in major anomalies【1】【2】【3】【4】.

Co‑amoxiclav should be avoided in women at high risk of preterm delivery because of a very low but documented risk of neonatal NEC; this recommendation stems from a 2001 trial on prophylactic antibiotics in preterm pre‑labor rupture of membranes and is reiterated in ERS guidance【1】【2】【3】【4】【5】.

First‑line therapy for respiratory tract infections in pregnant patients is supported by ERS guidance, which considers co‑amoxiclav safe when indicated【1】【2】【3】【4】.
For urinary tract infections with confirmed susceptibility, co‑amoxiclav is recommended (Gastroenterology Society guidance)【6】.
In intra‑abdominal infections related to inflammatory bowel disease, co‑amoxiclav is endorsed as an appropriate option (Gastroenterology Society guidance)【6】.
Surgical prophylaxis for cesarean section may include co‑amoxiclav, although cefazolin is preferred (Clinical Microbiology and Infection guidance)【7】.

When a pregnant woman has risk factors for preterm delivery (e.g., preterm labor, premature rupture of membranes, cervical insufficiency), ERS advises selecting an alternative antibiotic such as cefuroxime or azithromycin【1】【2】【3】【4】.

Co‑amoxiclav is compatible with breastfeeding; while ampicillin‑class antibiotics are excreted in milk, this does not contraindicate use (ERS guidance)【1】【2】【3】【4】.
Clinicians should be aware that antibiotics in breast milk may cause false‑negative cultures in febrile infants or transient gastro‑enteritis due to altered intestinal flora (ERS guidance)【1】【2】【3】【4】.

Plain amoxicillin holds a TGA Category A classification, whereas co‑amoxiclav is Category B1; both are considered compatible in pregnancy according to ERS recommendations【1】【2】【3】【4】.