Insights into the Physiology of Childbirth Using Transcriptomics

June 2006 | Volume 3 | Issue 6 | e276 Few biological processes as central to the survival of viviparous species are so incompletely understood as childbirth (parturition) [1]. Premature labor and prolonged gestation due to failure of labor to commence are associated with an increased risk for perinatal death and long-term handicap. Even when labor begins at term, “failure to progress” is so frequently diagnosed that at least 20% of all births occur through cesarean delivery, the most common operation performed worldwide. The rationale for performing a cesarean delivery in women whose cervix has failed to dilate in active labor (arrest of dilatation), or in whom the fetal head does not descend after complete dilatation of the cervix (arrest of descent), is that “failure to progress” is an indicator of cephalopelvic disproportion. However, this explanation is unlikely to be true in many cases, because a proportion of mothers with a previous cesarean delivery due to “failure to progress” in labor will deliver a larger baby vaginally in a subsequent pregnancy. Thus, a central question in reproductive biology is: what is “failure to progress” in labor? A “functional disorder,” rather than cephalopelvic disproportion, may be the underlying reason for a proportion of cesarean deliveries performed after labor has begun. Such “functional disorders” could be due to inadequate preparation of the uterine muscle (myometrium) and/or the cervix for labor. Indeed, accumulating evidence suggests that the myometrium develops a contractile phenotype as pregnancy approaches term and the cervix also undergoes preparatory changes [2]. The cellular and biochemical phenomena underpinning preparation of the uterine muscle and the cervix [3] are different and have been the focus of intensive investigation [4,5]. Insights into the Physiology of Childbirth Using Transcriptomics Roberto Romero, Adi L. Tarca, Gerard Tromp