- Pregnant women are more susceptible to candida infections than nonpregnant women. Since monocytes play a major role in host defense against candida, their association with radiolabeled candida and their capacity for killing candida were compared in sera of pregnant and nonpregnant women. While the basal rate of these monocyte functions was similar in both groups of women, candida opsonized with serum from pregnant women was less effective in enhancing these monocyte activities. Serum from nonpregnant women increased the association about twofold, whereas serum from pregnant women increased it only by about one and a half times in the two groups of women. Pretreatment of candida with serum from pregnant women increased the killing to 28%, whereas the serum from nonpregnant women was more effective, increasing the killing to 40%. The difference between the effect of the sera could not be attributed to the level of serum complement or IgG.