Prolonged pregnancy refers to gestation lasting 42 weeks or more. The cause is still unknown, but it may be related to changes in the fetal brain that initiate labor or a placental estrogen deficiency. As pregnancy progresses past 40 weeks, amniotic fluid levels decrease from 500-1000 ml to around 400 ml by 42-43 weeks. This decrease in amniotic fluid can lead to compression of the umbilical cord and reduced blood flow to the fetus, resulting in potential complications like meconium aspiration, hypoglycemia, or polycythemia in the fetus. If left untreated, this condition known as dysmaturity syndrome can occur in 1-2% of postmature fetuses and cause skin changes,

1. Prolonged Pregnancy By Donna Adelsperger RN, M.Ed

2. Prolonged Pregnancy Gestation of 42 weeks or more Term = 38 completed weeks till 41 completed weeks Postmaturity refers to what happens to fetus because of prolonged pregnancy

3. Prolonged Pregnancy-Etiology Cause is still unknown Some evidence that initiation of labor is related to sequential changes beginning in the fetal brain that does not occur 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

4. Prolonged Pregnancy- Normal Physiology Amniotic Fluid sources Maternal circulation Amniotic membranes Fetal plasma Volume changes by Fetal urine Fetal use of fluid for nourishment (swallowing) and it goes into GI tract

5. Prolonged Pregnancy- Normal Physiology Amniotic volume gradually  to 800-1200ml by @ 34 weeks AF then begins to  At 40 weeks gestation level is @ 500-1000 ml By 42-43 weeks levels @ 400ml

6. Prolonged Pregnancy- Normal Physiology Functions of AF Cushions fetus and cord Allows fetus to move freely Assists fetus in respiratory movements Facilitates lung development and surfactant production

7. Prolonged Pregnancy- Normal Physiology Placenta Exchange provides large surface area for materials to be exchanged between mom and fetus Functions Optimal function until @ 42 weeks then aging occurs (if it has not already begun)

8. Grading the Placenta

9. Placental Grading

10. Pathophysiology Amniotic Fluid Oligohydramnios – below 400ml Makes cord vulnerable which shuts off blood flow to and from placenta Meconium in AF occurs 25 – 30% of time With  AFV meconium is thick Inhibits normal antibacterial properties of AF Pulls fluid from Wharton jelly causing some stiffening of cord So bending of cord which causes kinking and  blood flow

11. Results of Pathophysiology Maternal weight loss as AF decreases Decreased AF (< 400 ml) and decrease in uterine size Advanced bone maturation i.e. fetal hard May result in lack of molding Potential for failure to progress (FTP) Potential for prolonged active phase of labor Potential for failure to complete transitional phase

12. Dysmaturity Syndrome Occurs 1-2% of postmature fetuses Skin changes occur with or without loss of subcutaneous fat, muscle mass, meconium staining depending on severity of cord compression and placental dysfunction First stage-loss of vernix Second stage-Green meconium stained skin and cord Third stage – yellow staining of skin and cord related to old meconium. Bile in meconium turns fluid yellow. Fetal hypoxia

13. Dysmaturity Syndrome Meconium aspiration Hypoglycemia due to anaerobic glycolysis using up CHO reserves Polycythemia -  production of RBCs as compensatory response to hypoxia hyperbilirubenemia

14. Pathophysiology Placenta and cord Aging causes fibrin and calcium deposits Intervillous hemorrhagic infarcts to occur Basal membrane of placental blood vessels thicken and degenerate affecting diffusion of oxygen