GP Rob Hicks replies:

Urinary tract infections (UTIs) are common in pregnancy since pregnancy hormones cause changes that make these infections more likely.
It's important that a UTI is treated because if it's not, it may lead to a kidney infection which, in addition to making you feel very ill, can cause premature labour.
Provided UTIs are treated roperly, youand your baby are unlikely to come to any harm.
The antibiotic you have been given, cefalexin, is commonly used and is thought to be safe in pregnancy.
It's important that you complete the course and then have your urine tested again to make sure the infection has cleared. To lessen the chances of you suffering another infection, drink plenty of liquid, go to the loo regularly and avoid 'holding on'.