Trip Answers

Question answered:19/05/08

In issues relating to teratology the NLH Primary Care Q&A Service would strongly recommend GPs and health workers to contact the National Teratology Information Service (NTIS) for the very latest information on drug and chemical safety during pregnancy or breast feeding.  Their phone number is 0191 232 1525.  They are a dedicated service and have better and more up-to-date information resources at their disposal.

 

CKS have a guideline on lower UTI in women [1] and this includes a specific section on UTI in pregnancy [2].  This reports:

 

“Acute lower urinary tract infection:

 

 - Send urine for culture.
 - Treat with an appropriate antibiotic for 7 days. First-line choices for empirical treatment are trimethoprim, nitrofurantoin, cefalexin, or amoxicillin — see cautions in Practical prescribing points.
 - Review progress with culture results and adjust treatment accordingly.
 - Send urine cultures to screen for asymptomatic bacteriuria 7 days after completion of treatment.
 - Treat pain and raised temperature with paracetamol.

 

Practical prescribing points
For further information please see the Medicines Compendium (www.medicines.org.uk) or the British National Formulary (www.bnf.org).

 

Trimethoprim is a folate antagonist, and there have been concerns over its use during pregnancy, as it may limit the availability of folic acid to the fetus and impair normal development.
 - In women with a low folate status (i.e. women with established folic acid deficiency or low dietary intake, or in those already taking known folate antagonists such as antiepileptics and proguanil), trimethoprim should be avoided unless the woman is also taking a folate supplement.
 - In women with normal folate status, short-term use of trimethoprim is unlikely to induce folate deficiency. Note: women who are pregnant, or at risk of pregnancy, should be taking folic acid until week 12 of their pregnancy in order to prevent neural tube defects in the fetus.
 - However, the BNF cautions against the use of trimethoprim in the first trimester of pregnancy because the manufacturers recommend that it not be used then. The manufacturer's information leaflet also advises against the use of trimethoprim for women who are pregnant or planning to become pregnant.

 

Nitrofurantoin should not be prescribed if the mother is glucose-6-phosphate dehydrogenase (G6PD)-deficient. It can otherwise be used during pregnancy, but should not be taken near term as it can cause haemolysis in the fetus.

 

Cefalexin is a broad-spectrum antibiotic and is therefore more likely to cause diarrhoea and vaginal thrush.
 - In high dosages cefalexin may cause diarrhoea, but can be taken with food or milk to try to avoid stomach upset.
 - Rarely, cefalexin may cause pseudomembranous colitis. If pseudomembranous colitis is suspected, stop cefalexin immediately.
 - During pregnancy — cefalexin has not been shown to cause harm to the fetus.
 - Women can continue to breastfeed while taking cefalexin. Low concentrations are present in breast milk, which may cause changes to the bacteria in the infant's gastrointestinal tract.”

 

References

1) http://cks.library.nhs.uk/uti_lower_women
2) http://cks.library.nhs.uk/uti_lower_women/management/quick_answers/scenario_lower_uti_in_pregnancy
 

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