Correlation between serum antichlamydial antibodies and tubal factor as a cause of infertility.

Although salpingitis frequently produces tubal damage and infertility, many women with tubal factor as a cause of their infertility do not have a clinical history of salpingitis. In order to investigate whether or not some such cases might be due to subclinical chlamydial infections, we measured antichlamydial antibodies in the serum of 172 women consecutively undergoing evaluation for infertility. Only 16 (9.3%) had a prior history of salpingitis. Sixty-one (35%) had antichlamydial antibodies (S+), and of these 75% had tubal factor as a sole or contributing cause of their infertility, versus 28% of the seronegative (S-) women (x2 - 34, P less than 0.001). There was no association between chlamydial seropositivity and any infertility factor other than tubal factor in multivariant analyses. Subclinical infections with Chlamydia trachomatitis may be a major cause of tubal infertility in the United States, and chlamydial serologic studies may be useful in identifying the subset of infertile women likely to have tubal factor.