Which of the following antibiotics is known to be safe during pregnancy?

Azithromycin is recognized for its safety profile during pregnancy, making it the correct choice in this context. It belongs to the macrolide class of antibiotics, which are generally preferred during pregnancy because they have not shown significant teratogenic effects in studies. Research indicates that azithromycin does not pose the same risks as some other antibiotics, which have been associated with complications in fetal development.

In contrast, levofloxacin, a fluoroquinolone, has been associated with potential risks, including cartilage damage and other adverse effects in developing fetuses. Tetracycline is known to cause tooth discoloration and could potentially affect bone development, making it unsuitable in pregnancy. Gentamicin, an aminoglycoside, carries risks such as ototoxicity and nephrotoxicity in both the mother and the fetus, thus it is typically avoided unless absolutely necessary.

Given these considerations, azithromycin stands out as the safest option among the listed antibiotics for use during pregnancy.