2, 3, 4 MECHANISM OF NORMAL LABORįor a successful normal labor a coordinated interaction of the uterine activity (power), maternal pelvis (passage) and fetus (passenger) is required. The onset of labor is also associated with an increase in prostaglandin production in the placental and cervix, furthering inducing their receptors and facilitating cervical ripening (PGE 2) and uterine contractions (PGF 2a). 1 This potentiates oxytocin receptors in the myometrium, reduces the progesterone/estrogen ratio and upregulates myometrial gap junctions to facilitate uterine contractions. Fetal dehyroepiandrosterone sulfate (DHEAS) is converted to estriol and estradiol by the placenta. Complex interactions of hormones between uterus, placenta and fetus. The factors that trigger labor at term are not clearly understood it is postulated that it is a result of changes in the hypothalamic–pituitary–adrenal axis, increasing fetal cortisol, and placental enzymatic functions. World Health Organization defines normal labor as starting spontaneously at term (37 completed weeks of gestation) for a fetus with cephalic presentation, progressing without maternal or fetal complication, and resulting in the delivery of fetus followed by placenta and membranes. The mechanism of normal labor is series of events that take place in the genital organ that allow the birth of a viable fetus at term followed by expulsion of placenta and membrane from the vagina. See end of chapter for details INTRODUCTION By completing 4 multiple-choice questions (randomly selected) after studying this chapter readers can qualify for Continuing Professional Development awards from FIGO plus a Study Completion Certificate from GLOWM
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |