Statistical analysis
Clinical data, gynecological, laboratory and demographic variables of
each participant were collected from their medical records. Independent
variables associated to risk factors were: age, educational attainment,
skin color, marital status, income, age at onset of sexual intercourse,
number and previous abortion history. Data were analyzed by SPSS Version
12.0. The Chi-square and Poisson regression was also performed.
Significant differences were considered when P values were lower
than 0.05.