Primary predictors of preterm labour

Abstract

Spontaneous preterm birth accounts for 60% of all preterm births in developed countries. With the increase in multiple pregnancies, induced preterm birth and the progress in neonatal care for extremely preterm neonates, spontaneous preterm birth for singleton pregnancies in developed countries has probably decreased over the past 30 years. This decrease is likely to be related to better prenatal care for all pregnant women because the recognition of primary risk factors in early or late pregnancy remains a basic part of prenatal care. The failure to distinguish between induced and spontaneous preterm labour in most population-based studies makes it difficult to interpret results with respect to the primary predictors of preterm labour. Many such primary predictors of preterm labour have been used over the past 20 -30 years. These include individual factors, socio-economic factors, working conditions and obstetric and gynaecological history. Risk scores have been proposed in order to produce these data. Unfortunately, the predictive value of these scores, especially their specificity, is poor, mainly because all of these factors are indirect. We still cannot identify the mechanisms that lead to preterm labour and birth. New markers more directly related to preterm labour have recently been proposed, some of which relate to direct causes of preterm labour such as cervical ultrasound measurement, fetal fibronectin (FFN), salivary estriol, serum CRH and bacterial vaginosis. Several of these have predictive values, which are potentially useful for clinical practice. Nonetheless, pregnant women in developed countries are already closely monitored throughout pregnancy. Before proposing new screening tests to be applied systematically to all pregnant women, their advantages and drawbacks must be fully evaluated.

Effect of 17-α hydroxyprogesterone caproate on the production of tumor necrosis factor-α and the expression of cyclooxygenase-2 in lipopolysaccharide-treated gravid human myometrial explants

“…31,32 Given the multifactorial causes of preterm birth, elucidating the mechanism by which 17-OHPC reduces the risk for recurrent preterm birth will continue to be challenging. [33][34][35][36][37] Although the American Congress of Obstetrics and Gynecology recommends the use of progesterone in women with a previous history of spontaneous preterm birth, there are still many unknowns regarding the mechanism of actions of the progesterone agents prescribed for women with a history of preterm birth. 38 Future research is needed to understand how these agents alter physiological processes to produce clinical effects.…”

PAPP-A levels as an early marker of idiopathic preterm birth: a pilot study

“…23,24 No marker has been PAPP-A as marker for preterm birth S Grisaru-Granovsky et al implicated in large low-risk populations or has its use been validated against reduction of preterm birth. 23,24 Moreover, in practice, the use of fibronectin in the cervicovaginal secretion is limited and may be delayed by the presence of blood, leaking amniotic fluid, intercourse in the previous 24 h, previous digital examination and/or the use of transvaginal ultrasound scan gel. 25 The most recent evidence points to amniotic fluid inflammatory interleukins as having high predictive value for preterm delivery.…”

Vaginal micronized natural progesterone treatment and reduced risk of recurrent preterm birth

“…This may be due to small number of study population and it is the main limitation of our study. Short cervical length is one of the most important risk factor in PTB [21][22][23][24], and progesterone treatment is effective in reducing the risk of PTB in women with short cervical length [15,16]. Fetal Medicine Foundation reported a trial of approximately 24,000 low-risk women who were routinely checked for cervical length during their prenatal care [15].…”

“…Early prediction and prevention is the most effective management of PTB. With the advances in obstetrics, a great advances were made in identification of risk factors for PTB, as well as early prediction of PTB such as measurement of cervical length and cervicovaginal fibronectin [21][22][23][24]. Risk factors of spontaneous PTB include prior history of PTB, ethnicity of pregnant women, multiple pregnancies, smoking, uterine anomaly and history of curettage or cervical conization [1,5].…”