Table 3.

Main antibiotics for pregnant women with urinary tract infections

Drug	Characteristics	FDA
Usually considered as safe, when needed [278 – 280, 304, 340, 350 – 354]
Semi-synthetic penicillin	Ampicillin and Amoxicillin are the first-choice antibiotics	B
Clavulanic acid	Bacterial beta-lactamase inhibitor, used in combination with Amoxicillin. The association with beta-lactamase inhibitors is indicated when therapy with only Penicillins and Cephalosporins is not effective
1st and 2nd generation Cephalosporins	In general, the data available on the use of Cephalosporins, in particular of first and second generation, during pregnancy, does not indicate an increase, over the expectation, of congenital abnormalities on exposed new-borns
3rd generation Cephalosporins	Indicated for acute pyelonephritis when parenteral administration is necessary. Cefepime and Ceftriaxone: animal studies do not show teratogenic effects. Ceftriaxone should be avoided during the days before delivery because of the possibility of kernicterus (it competes with bilirubin for the binding with albumin)	B
Carbapenems	Meropenem should be the first choice in cases of notable severity, according to sensitivity. Animal studies, in fact, showed adverse effects on the foetus with Imipenem-cilastatin	B
Aztreonam	Valid alternative in the case of allergy to beta-lactams when parenteral administration is necessary	B
Macrolides	Erythromycin represents a valid alternative in the case of allergy to beta-lactams. Clarithromycin and Azithromycin are a second choice but they could be used according to clinical conditions [302]	B
Phosphomycin	Indicated for uncomplicated urinary tract-infections [297, 298, 303]	B
Nitrofurantoin	Contraindicated in G6PDH-deficient women. Their use during the first trimester should be limited to those situations in which no alternative therapies are available. Contraindicated at the end of the pregnancy (38th–40th week) and during delivery because of the risk of haemolytic anaemia in the new-born [26, 305]	B
To be avoided
Aminoglycosides	They have been associated with ototoxicity. Their use must be avoided	D
Fluoroquinolones	Preclinical animal studies demonstrated abnormalities in the development of cartilages. Ciprofloxacin is not a first-choice drug during pregnancy; its administration should be limited to those cases in which the benefits are greater than the risk connected to the therapy [307]	C
Tetracycline	Their use must be avoided	D
Sulphonamides	Trimethoprim sulfamethoxazole must be avoided during the first trimester (it is a folic acid—antagonist) and at the end of the pregnancy for the risk of kernicterus	D

FDA Classification [340]: A, controlled human studies show no risk; B, no evidence of risk in studies; C, risk cannot be ruled out; D, positive evidence of risk; X, contraindicated in pregnancy