Bacteriuria in Pregnancy
It is important to treat asymptomatic bacteriuria early in pregnancy as about 30% of cases can progress to pyelonephritis which is associated with premature delivery.
In 2019 the USPSTF recommended screening for asymptomatic bacteriuria in pregnant adults and against it in nonpregnant adults. This can be best achieved by using a midstream, clean-catch urine culture at the first prenatal visit or at 12 to 16 weeks of gestation, whichever happens earlier.
A urine culture showing >100,000 CFU/mL of any single bacteria or >10,000 CFU/mL if the bacteria is group B streptococcus indicates treatment. A 7 day course of antibiotic choice is preferred over others. Treatment is important due to fear of UTI and Pyelonephritis.
Choose antibiotic which is safe in the current trimester. Avoid penicillins due to E.coli resistance.
Nitrofurantoin (Macrodantin) can be given except for the last two weeks due to fear of anemia development in the fetus. It is usually the drug of choice as most common cause of bacteriuria is E. coli.
An alternative choice would be Fosfomycin (Monurol) one dose and is usually used with resistant organisms.
Don't use Fluoroquinolones in the first trimester. Fluoroquinolones like ciprofloxacin and norfloxacin can be used in the second and third trimester if no alternative is available.
Cephalosporins like as cephalexin (Keflex), cefuroxime (Ceftin) and cefadrozil (Duricef) can be used in the first and second trimester. Don't give cephalosporins in the third trimester due to interference with vitamin K metabolism and risk of allergic reactions.
Bactrim and Ciprofloxacin, pregnancy category C, are usually not used in pregnancy especially during the first trimester due to fetus malformation risks. Sulfonamides can cause kernicterus towards the third trimester especially in preterm infants.
This post covers the points you need to know for your board exams as well as for teaching residents on the daily rounds. Medical professionals can't use the information here to treat their patients nor people can use the information her to treat themselves. If you are having any medical issues, contact your local emergency services or your primary care provider. Please refer to your doctor for medical advice.