Preterm birth is a dramatic event for the infant born too early, causing distress for child and parents while also burdening both parents and society. The ineffectiveness of interventions directed towards known risk factors highlights the lack of understanding of plausible causal pathways. The recent transdisciplinary involvement of methodologists and scientists from various disciplines, including psychosocial scientists, may provide land mark advances in innovative interventions to reduce the preterm birth rate worldwide.
Circumstantial evidence already supports part of these pathways where epidemiologists, clinicians, physicosocial and basic scientists shared their results taking into account that the host susceptibility (a pregnant woman with her own innate and acquired personality traits) may interact with several agents (acute or chronic exposure risks) and the environtment (social and cultural context, gender, poverty etc)
Recent advances in the pathophysiological processes leading to the disruption of uterine quiescence and cervical changes with or without rupture of the membranes identified a few plausible pathways linking underlying biological and psychosocial factors. These included genetic susceptibility, maternal and/or fetal biological/pychosocial stress, inflammatory/infectious causes and mechanical condition.
Descriptive associations of risk factors have been of a tremendous help in attempting to identify high risk pregnancies for preterm delivery. However the strongest risk factors (previous preterm birth) is nonexistent for the majority of all preterm births among primiparas. In addition, a substantial proportion of preterm premature rupture of membranes and spontaneous preterm birth occur without any apparent cause.
Preterm birth, whether medically indicated, due to preterm premature rupture of membranes or from spontaneous preterm labour, is multifactorial, but may share similar underlying aetiological mechanisms. Similar observations were reported by Berkowiitz where some medical conditions (eg diabetes, hypertension) were significantly associated with all categories togethers with a previous history of preterm birth or uterine abnormality, ethnicity and inappropriate prenatal care. Sociodemographics, lifestyle or some obstetrical characteristics differed accros categories.
A prospective survey, carried out in the Quebec City. This study substantiates that several risk factors of spontaneous preterm labour cannot be modified (previous intra uterine growth restriction, previous preterm labour) while others may respond to targeted interventions (BMI before conception, screening and appropriate treatment of urinary tract infections, avoidance of strenuous working conditions together with initiating appropriate intervensions and/or counselling when anxiety and stressful life events occur during pregnancy)
Numerous descriptive studies have highlighted the aetiological heterogeneity of preterm birth, emphasizing its multifactorial origins. A classical epidemiological review acertained well established risk factors: previous low birth-weight or preterm delivery, repeated second trimester abortion, uterine and cervical anomalies, in-vitro fertilization, muliple pregnancy, maternal medical complications, gestasional bleeding, abnormal placentation, urogenital infection, Afro-American ethnic origin, low socio-economic status, social isolation, smoking and low body mass index (BMI) before conception. Other factors such as maternal age, parity, infertility, heredity, drug abuse, strenuous physical work-load, sexual activities, psychosocial stress or stressful life events, inadequate or no prenatal care, maternal weigh gain are still debate