Chlamydia Tracomatis and Other Lower Genital Tract Infections Among Women With Unexplained Early Miscarriage
Condition: Early Pregnancy
MeSH terms: Reproductive Tract Infections; Abortion, Spontaneous
Study type: Observational

Summary: 
      Although one fourth of pregnant women experience at least 1 abortion, yet only 50% of causes
      are identified. Pregnancy loss can result from viral, bacterial, and other infections. It can
      reach the fetoplacental units through blood born or local spread. Lower genital tract
      infections- a potentially preventable infections- was suggested as a cause of spontaneous
      miscarriage. It was reported in 15 and 66% of early and late miscarriages respectively. These
      infections are also commonly encountered among apparently healthy looking pregnant women with
      an overall prevalence of 40-54%. If left untreated it can lead to premature rupture of the
      membranes, preterm birth, low birth weight, Fetal loss, neonatal ophthalmic and pulmonary
      damage.
    

Detailed description: 
      Abortion was defined by the World Health Organization and the National Center for Health
      Statistics as pregnancy termination before 20 weeks of gestational age or fetal weight
      smaller than 500 grams. Abortion is termed early or late if it occurs before 12 weeks or
      between 12 and 24 weeks of gestation respectively.

      Spontaneous abortion prevalence is not exactly known as it varies according to the used
      method of identification. Wilcox and colleagues in 1988 reported a prevalence of 31 % of
      pregnancy loss after implantation and over 2/3 of them were clinically silent.

      Although one fourth of pregnant women experience at least 1 abortion, yet only 50% of causes
      are identified. Pregnancy loss can result from viral, bacterial, and other infections. It can
      reach the fetoplacental units through blood born or local spread.

      Lower genital tract infections- a potentially preventable infections- was suggested as a
      cause of spontaneous miscarriage. It was reported in 15 and 66% of early and late
      miscarriages respectively. These infections are also commonly encountered among apparently
      healthy looking pregnant women with an overall prevalence of 40-54%. If left untreated it can
      lead to premature rupture of the membranes, preterm birth, low birth weight, Fetal loss,
      neonatal ophthalmic and pulmonary damage.

      The suggested mechanisms that genital tract infection can cause abortions are encountered are
      fetal or placental infection with production of toxic metabolites.

      Some organisms like Brucella abortus, Campylobacter fetus, and Toxoplasma gondii can cause
      abortion in livestock. Their effects in human is unclear. Most infections were not linked to
      abortions except Chlamydia trachomatis, which was detected in 4% of abortuses compared with <
      1 percent of controls.

      Chlamydia trachomatis infection incidence was markedly increased in the last years and is
      responsible for many gynecological conditions as pelvic inflammatory disease and infertility
      and pregnancy complications as preterm birth and premature rupture of membranes but its
      relation to early pregnancy loss remains unrecognized.

      Baud et al assumed an association between miscarriage and serologic/molecular evidence of C.
      trachomatis infection. This was evident by the higher prevalence of immunoglobulin G against
      C. trachomatis in the miscarriage group than in the control group (15.2% vs. 7.3%; p = 0.018)
      that remained significant after adjustment for age, origin, education, and number of sex
      partners (odds ratio 2.3, 95% confidence interval 1.1-4.9).

      Polymicrobial infection was associated with 2 - 4fold increase in abortion. Data concerning a
      link between some other infections and increased abortion are conflicting. Oakeshott and
      coworkers (2002) reported an association between second-, but not first-, trimester
      miscarriage and bacterial vaginosis with a relative risk of miscarriage before 16 weeks'
      gestation of 1.2 (0.7 to 1.9).

      The present study is designed to determine prevalence of genital tract infections and its
      relation to occurrence of early miscarriage in women with recent unexplained spontaneous
      miscarriages
    

Intervention name(s): cervicovaginal culture and qPCR for chlamydial trachomatis and wadallia chondrophila
Intervention type(s): Diagnostic Test
Intervention description(s): three cervicovaginal swabs were obtained: one was used for a smear test of vaginal fluid pH evaluation and direct microscopy, the second swabs, cultured for aerobic and anaerobic bacteria and yeasts, the third was eluted in 2-sucrose-phosphate (2SP) based transport medium. Placental samples from the study group were cultured for aerobic and anaerobic bacteria. Placenta sample and 2SP medium were stored at -80°C until their analysis by real time PCR (qPCR)
Other intervention name(s): placental culture and qPCR; study group only
Observational model: Case-Control
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        The study group included 300 women presenting with unexplained spontaneous miscarriage. The
        control group included 300 women with normal pregnancy, recruited from women attending the
        antenatal clinic of gestational age 8-18 weeks.

        All participants were subjected to full history, careful general and abdominal examination,
        Cervicovaginal swabs, urine and blood sampling in addition to placental sampling from study
        group.
      
Biospecimen description: 
      cervicovaginal swabs, serum samples and placental tissues