Prolonged pregnancy


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Prolonged pregnancy

  1. 1. Prolonged Pregnancy By Donna Adelsperger RN, M.Ed
  2. 2. Prolonged Pregnancy <ul><li>Gestation of 42 weeks or more </li></ul><ul><ul><li>Term = 38 completed weeks till 41 completed weeks </li></ul></ul><ul><li>Postmaturity refers to what happens to fetus because of prolonged pregnancy </li></ul>
  3. 3. Prolonged Pregnancy-Etiology <ul><li>Cause is still unknown </li></ul><ul><li>Some evidence that initiation of labor is related to sequential changes beginning in the fetal brain that does not occur </li></ul><ul><li>There may be a placental estrogen deficiency or decreased release of prostaglandins by decidua and fetal membranes resulting in decreased stimulation to form oxytocin receptors in myometrium </li></ul>
  4. 4. Prolonged Pregnancy- Normal Physiology <ul><li>Amniotic Fluid sources </li></ul><ul><ul><li>Maternal circulation </li></ul></ul><ul><ul><li>Amniotic membranes </li></ul></ul><ul><ul><li>Fetal plasma </li></ul></ul><ul><li>Volume changes by </li></ul><ul><ul><li>Fetal urine </li></ul></ul><ul><ul><li>Fetal use of fluid for nourishment (swallowing) and it goes into GI tract </li></ul></ul>
  5. 5. Prolonged Pregnancy- Normal Physiology <ul><li>Amniotic volume gradually  to 800-1200ml by @ 34 weeks </li></ul><ul><li>AF then begins to  </li></ul><ul><li>At 40 weeks gestation level is @ 500-1000 ml </li></ul><ul><li>By 42-43 weeks levels @ 400ml </li></ul>
  6. 6. Prolonged Pregnancy- Normal Physiology <ul><li>Functions of AF </li></ul><ul><ul><li>Cushions fetus and cord </li></ul></ul><ul><ul><li>Allows fetus to move freely </li></ul></ul><ul><ul><li>Assists fetus in respiratory movements </li></ul></ul><ul><ul><li>Facilitates lung development and surfactant production </li></ul></ul>
  7. 7. Prolonged Pregnancy- Normal Physiology <ul><li>Placenta </li></ul><ul><ul><li>Exchange provides large surface area for materials to be exchanged between mom and fetus </li></ul></ul><ul><li>Functions </li></ul><ul><ul><li>Optimal function until @ 42 weeks then aging occurs (if it has not already begun) </li></ul></ul>
  8. 8. Grading the Placenta
  9. 9. Placental Grading
  10. 10. Pathophysiology <ul><li>Amniotic Fluid </li></ul><ul><ul><li>Oligohydramnios – below 400ml </li></ul></ul><ul><ul><li>Makes cord vulnerable which shuts off blood flow to and from placenta </li></ul></ul><ul><ul><li>Meconium in AF occurs 25 – 30% of time </li></ul></ul><ul><ul><ul><li>With  AFV meconium is thick </li></ul></ul></ul><ul><ul><ul><li>Inhibits normal antibacterial properties of AF </li></ul></ul></ul><ul><ul><ul><li>Pulls fluid from Wharton jelly causing some stiffening of cord </li></ul></ul></ul><ul><ul><ul><li>So bending of cord which causes kinking and  blood flow </li></ul></ul></ul>
  11. 11. Results of Pathophysiology <ul><li>Maternal weight loss as AF decreases </li></ul><ul><li>Decreased AF (< 400 ml) and decrease in uterine size </li></ul><ul><li>Advanced bone maturation i.e. fetal hard </li></ul><ul><ul><li>May result in lack of molding </li></ul></ul><ul><ul><li>Potential for failure to progress (FTP) </li></ul></ul><ul><ul><li>Potential for prolonged active phase of labor </li></ul></ul><ul><ul><li>Potential for failure to complete transitional phase </li></ul></ul>
  12. 12. Dysmaturity Syndrome <ul><li>Occurs 1-2% of postmature fetuses </li></ul><ul><li>Skin changes occur with or without loss of subcutaneous fat, muscle mass, meconium staining depending on severity of cord compression and placental dysfunction </li></ul><ul><ul><li>First stage-loss of vernix </li></ul></ul><ul><ul><li>Second stage-Green meconium stained skin and cord </li></ul></ul><ul><ul><li>Third stage – yellow staining of skin and cord related to old meconium. Bile in meconium turns fluid yellow. </li></ul></ul><ul><li>Fetal hypoxia </li></ul>
  13. 13. Dysmaturity Syndrome <ul><li>Meconium aspiration </li></ul><ul><li>Hypoglycemia due to anaerobic glycolysis using up CHO reserves </li></ul><ul><li>Polycythemia -  production of RBCs as compensatory response to hypoxia </li></ul><ul><ul><li>hyperbilirubenemia </li></ul></ul>
  14. 14. Pathophysiology <ul><li>Placenta and cord </li></ul><ul><ul><li>Aging causes fibrin and calcium deposits </li></ul></ul><ul><ul><li>Intervillous hemorrhagic infarcts to occur </li></ul></ul><ul><ul><li>Basal membrane of placental blood vessels thicken and degenerate affecting diffusion of oxygen </li></ul></ul>