Prescribing Antimicrobials in Pregnancy and Lactation: Guidelines for Prescribers

The treatment options for pregnancy and postpartum infections are meant as guidelines for prescribers, they do not replace clinical judgment but augment it. These prescribing guidelines have been developed after review of national and international guidelines and current practice, expert opinion, clinical consensus and published evidence where it exists.

Before prescribing antimicrobials for pregnant women, clinicians should also consider the following:

• Local antimicrobial sensitivities and resistance data.
• Previous antimicrobial treatment the woman has been prescribed for the current and previous infections during this pregnancy.
• The allergy status of the woman.
• Exposure of the fetus to the prescribed antimicrobial and its possible teratogenicity.
• Concurrent medication that the woman is taking.
• The stage of pregnancy.
• Concurrent morbidities.
• Further information on the use of antimicrobials in pregnancy for healthcare professionals is available in the individual drug’s SmPC on the HPRA website and the UK Teratology Information Service.
• The National Medicines Information Centre clinical enquiry answering service is available to prescribers in Ireland should further information about the use of their chosen antimicrobial(s) in pregnancy or lactation be required. Contact details for the NMIC.

Lactation

• The excretion of most drugs in breast milk is low but the possibility should be discussed with mothers and latest guidance checked on individual drug's SmPC on the HPRA website.
• The National Institute of Health in the USA have a useful database called LactMed which may provide other useful information on safety in breastfeeding. Further information is also available from the NHS Specialist Pharmacy Service Safety in Breastfeeding Resource. (Search for the drug name, filter Guidance by Safety in Breastfeeding category and click on the drug name for ‘Lactation Safety Information’ section).
• The conditions listed on the web link below are either pregnancy-specific conditions for which a GP may need to initiate antimicrobial therapy e.g. postpartum endometritis or a non-pregnancy specific infection that occurs in a pregnant woman e.g. influenza.
• GPs need to consider that any female of childbearing age could be pregnant when prescribing antimicrobials.

Guidelines for treatment of specific pregnancy and postpartum infections are available

Patient Information

• Bumps – Best use of medicines in pregnancy (from UK Teratology Information Service).
• Mother to Baby website (USA) for information on use of drugs in pregnancy and breast-feeding (Search or Use Browse by Medications category).
• An information sheet on Antibiotics and breastfeeding is available from the Breastfeeding Network UK.
• HSE My Child is a useful resource for breastfeeding support and general guidance.

Reviewed April 2025