Abstract
Objective Both history of spontaneous preterm birth (sPTB) and shorter interpregnancy intervals
(IPIs) increase the risk of recurrent sPTB. Mechanisms underlying the association
between IPI and recurrent sPTB are unknown. We have previously demonstrated that higher
concentrations of cervical anti-inflammatory cytokines are a risk factor for sPTB
and upper genital tract inflammation. Here, we examine the association between IPI
and cervical anti-inflammatory cytokines among women with previous sPTB.
Patients and Methods A prospective cohort of 73 women with previous sPTB and cervical interleukins (IL-4,
IL-10, and IL-13) measured at < 16 weeks. Using the published principal factor analysis,
the anti-inflammatory (ANTI) score was calculated. From our previous work, higher
ANTI scores increase the subsequent risk of sPTB. IPI was the time from the previous
birth to the conception of current pregnancy. Confounders included education level,
marital status, gonorrhea, chlamydia, body mass index, race, and cigarette smoking.
IPI and ANTI score were analyzed using univariable and multivariable analyses.
Results There was a significant negative linear relation between IPI and ANTI score (β =
−0.075, p = 0.017). This persisted after adjustment for confounders (p = 0.02). As IPI decreases by 1 month, the ANTI-score–associated risk of sPTB increases
approximately by 4%.
Conclusion Among women with previous sPTB, there was a significant negative linear relation
between IPI and ANTI score.
Keywords
cervix - cytokines - inflammation - interpregnancy interval - preterm birth
