Aerobic and anaerobic flora of the cervix during pregnancy and the puerperium.

Comparison of species of bacteria isolated from patients with endometritis with species isolated from normal pregnant and nonpregnant women suggests that bacteria causing infections are indigenous to the genital tract. However, complete studies of the flora of pregnant women, especially anaerobic flora, are lacking. Aerobic and anaerobic cultures of the endocervix were obtained from women in all trimesters of pregnancy and at three days and six weeks post partum. The incidence of occurrence of each species of bacteria and the average number of different species per culture were determined for each period. The most prevalent organisms in each period were aerobic gram-positive rods and cocci and anaerobic gram-positive cocci. The average number of species of aerobic bacteria per culture remained approximately the same in each culture period. The average number of anaerobic species per culture decreased as pregnancy progressed, peaked on the third postpartum day, and at six weeks post partum returned to a level similar to that of the first trimester.