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
  • It is important to recognise that antibiotics should be administered during pregnancy at the upper end of their suggested dosing ranges, as pregnant women have an increased GFR and volume of distribution ranges are higher e.g. for strep tonsillitis use 666mg dose Calvepen® rather than 333mg dose.
  • 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 also the HSE Medication Guidelines for Obstetrics and Gynaecology: Antimicrobial safety in Pregnancy and Lactation and the UK Teratology Information Service


  • 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 HSE Medication Guidelines for Obstetrics and Gynaecology: Antimicrobial safety in Pregnancy and Lactation or the UK Drugs in Lactation Advisory Service (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 that 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 needed to consider that any female of childbearing age could be pregnant when prescribing antimicrobials.

Pregnancy and postpartum Infections

Patient Information

Reviewed May 2022

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