Population-Based Study of Prediagnostic Antibodies to Chlamydia trachomatis in Relation to Adverse Pregnancy Outcome

Abstract

Our findings confirm the association between previous exposure to C. trachomatis and ectopic pregnancy. We found no association between C. trachomatis seropositivity and miscarriage or preterm birth.

Chlamydia trachomatis and the risk of spontaneous preterm birth, babies who are born small for gestational age, and stillbirth: a population-based cohort study

“…Firstly there is a lack of consistent outcome definition. Some studies have not distinguished spontaneous preterm births from all other preterm births 5,6,9,12,13,18,19,[21][22][23] and in many high-income countries a substantial proportion of preterm births are planned (by labour induction or prelabour caesarean section) to manage obstetric conditions such as hypertensive diseases. 2 Similarly many studies report on low birth weight without taking into account gestational age and therefore do not clearly distinguish this outcome from preterm birth.…”

“…13,15,21,23 Thirdly some studies do not consider potential confounders such as the presence of other genital infections, maternal smoking and ethnicity, and therefore have been unable to account for these factors when quantifying associations. 8,9,12,22 Lack of consideration of such factors can lead to false positive results. For example much chlamydia screening has focussed on young women with multiple sexual partners.…”

“…Furthermore, the cohort design, with ascertainment of outcomes and exposures (chlamydia testing information) from independent sources (perinatal register and pathology data respectively), reduced the likelihood of biased reporting. On systematic searching of the literature, we identified four studies larger than this report to have examined the association between chlamydia infection and preterm birth 13,21,22 including one from our research team. 15 However, three lacked information on actual testing for chlamydia (ie.…”

“…3 Furthermore, randomised placebo-controlled prevention trials of antibiotics (including azithromycin) given during the antenatal period to high-risk women have found no effect on the rates of preterm birth. 4 Findings from observational studies have been inconsistent with most, [5][6][7][8][9][10][11][12][13][14][15] but not all, [16][17][18][19][20][21][22] suggesting chlamydia infection increases the risk of preterm birth. There is similar discordance in studies examining the effects of chlamydia infection on birth weight and stillbirth.…”

Maternal Antibodies to Chlamydia trachomatis and Risk of Gastroschisis

“…CT IgG antibodies decrease with time since infection, with evidence of a decrease in antibodies six months after infection followed by a plateau, but have been observed to remain detectable years after infection and are, therefore, useful in identifying a past infection. Samples from the Finnish Maternity Cohort have previously been used to report on a well‐established association between IgG antibodies to CT and ectopic pregnancy (Rantsi et al, ), providing support for the validity of using these samples for classification of CT exposure. Additional strengths include the medical record review of gastroschisis cases by a clinical geneticist and the use of the Medical Birth Register for control selection, which captures nearly all birth in Finland.…”