Is Vertical Transmission of Chlamydia trachomatis a Health Problem in Spain?

Background: C. trachomatis infection is the most prevalent sexually transmitted disease (STD) in Europe. Maternal infection increases the risk of premature rupture of membranes and low birthweight and could be transmitted to the newborn through the birth canal, eventually causing nasopharyngitis, conjunctivitis and pneumonia.

Objective: The main objectives were to analyse the prevalence of C.trachomatis infection in young women and the rate of transmission to the newborn. Secondary objective was to evaluate the need for screening programs for C. trachomatis in this population.

Methods: We conducted a prospective and interventional pilot study of 71 pregnant women aged 15-25 years. Polymerase chain reaction (PCR multiplex BDmax) for STD (Chlamydia, Neisseria gonorrhoeae, Trichomonas) was performed in a urine sample during the postpartum-period.

Newborns from C. trachomatis infected mothers were tested for Chlamydia using PCR in nasopharyngeal aspirate and urine samples. Mothers were interrogated about Chlamydia symptoms in the newborns.

Results: Median age was 23 years (IQR 17-23) and 70% were immigrants, most of them (60%) from Central and South America. The prevalence of Chlamydia infection was 19.7% (14 cases, 70% from immigrant mothers). We also detected 2 N. gonorrhoeae and 3 Trichomonas infections. Two infected mothers presented premature rupture of membranes (at 36 weeks gestation) but no newborn had low birthweight. Two children born to infected women (14%) were positive for Chlamydia. One infant had positive PCR in both urine and nasopharyngeal aspirate, and developed conjunctivitis. The other one had a positive PCR in urine and developed no symptoms. Both mothers and infected infants were treated with azithromycin.

Conclusions: We have found a high prevalence of Chlamydia infection in young pregnant woman, with a 14% rate of perinatal transmission. Our results support the need for screening programs in this target population.