Cytomegalovirus seroprevalence in French pregnant women: parity and place of birth as major predictive factors.

In this study we present data on cytomegalovirus (CMV) seroprevalence in pregnant women in France. One thousand and eighteen women were enrolled in a prospective study carried out in Grenoble. The overall rate of seropositivity, using a specific IgG ELISA test, was 51.5 % (95 % CI: 48.5-54.5). Among a homogeneous population of 873 women born in France with high or middle socioeconomic status, CMV seropositivity increased with age and parity. The seroprevalence according to age was found to depend on parity. It increased with age in women with no children or with only one; it was higher but no more age-dependent in women with two children or more. In addition, CMV seroprevalence was significantly higher in women born in southern France (51.6%) than in those born in northern France (37.4%), these findings being consistent with the existence, within France, of a gradient in seroprevalence rate, increasing from the North to the South. A logistic regression analysis reveals the place of birth in France as a major predictive factor of CMV antibody status (OR: 3.5) followed by age (OR: 2) and parity (OR: 1.7). In this study, we show an independent effect of parity on CMV seroprevalence, arguing for the importance of child-to-mother transmission; nevertheless, the latitude of the place of birth, even within a size-limited country such as France, appears to be a major predictive factor of CMV seroprevalence.