This cross-sectional seroprevalence study was carried out in 2007 to estimate the immunological status associated with poliomyelitis among fertile women , according to demographic changes. We consecutively enrolled 493 healthy mothers at the time of delivery in order to assess immunity against poliomyelitis by a neutralisation inhibition test. Despite the lack of seronegative subjects, our investigation showed low GMTs, which confirmed a reduction in the "booster effect". The GMTs against poliovirus 1, poliovirus 2 and poliovirus 3 were 25.20, 14.79 and 8.80, respectively. The data that emerged from our survey showed that GMTs have decreased significantly since 1983 and reached low-to-medium values over the past 25 years. The serum prevalence studies, together with the vaccination coverage estimates, are useful and are strongly recommended in order to highlight and identify the possible scenarios in which susceptible subject groups may be present simultaneously as well the possibility of the reintroduction of wild virus in an area that was previously free of polio.