USE OF PHENOXYMETHYLPENICILLIN (PENICILLIN V) IN PREGNANCY
Date of issue: September 2026, Version: 3.0
Phenoxymethylpenicillin is a penicillin antibiotic indicated for the treatment of pneumonia, bronchitis, bacterial pharyngitis, otitis media, and skin and soft tissue infections.
The limited data do not suggest an increased risk of congenital malformations, miscarriage, intrauterine death, low birth weight (LBW), preterm delivery, or neonatal complications following prenatal exposure to phenoxymethylpenicillin. Where possible associations with adverse outcomes have been suggested, findings are considered likely influenced by the effects of maternal infection during pregnancy.
Where possible, the results of culture and sensitivity tests should be available before making a treatment choice in accordance with local prescribing guidelines. It is important to ensure adequate treatment of infection in order to avoid adverse maternal and fetal effects from uncontrolled infection or pyrexia.
The Royal College of Obstetricians and Gynaecologists (RCOG) advises routine intrapartum antibiotic prophylaxis (IAP) for all women in preterm labour, with or without pre-labour rupture of membranes (PROM). Benzylpenicillin should be used preferentially, but a cephalosporin should be used in women with a non-severe penicillin allergy, or vancomycin where the allergy is severe. The National Institute for Health and Care Excellence (NICE) guidelines also state that women with pre-labour PROM should be offered oral erythromycin (250mg, 4 times a day) for a maximum of 10 days or until the woman is in established labour (whichever is sooner), with oral penicillin offered to women who cannot tolerate erythromycin.
Exposure to phenoxymethylpenicillin at any stage in pregnancy would not usually be regarded as medical grounds for termination of pregnancy or any additional fetal monitoring. However, other risk factors may be present in individual cases which may independently increase the risk of adverse pregnancy outcome. Clinicians are reminded of the importance of consideration of such factors when performing case-specific risk assessments.
This is a summary of the full UKTIS monograph for health care professionals and should not be used in isolation. The full UKTIS monograph and access to any hyperlinked related documents is available to NHS health care professionals who are logged in.
If you have a patient with exposure to a drug or chemical and require assistance in making a patient-specific risk assessment, please telephone UKTIS on 0344 892 0909 to discuss the case with a teratology specialist.
If you would like to report a pregnancy to UKTIS please click here to download our pregnancy reporting form. Please encourage all women to complete an online reporting form.