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Station 5 Dr A Cassim At this station examine the placenta provided. Station Learning Objectives: 1. Familiarise yourself with the examination of the placenta and be alert to potential abnormalities. 2. Using the charts prepared revise a. The anatomy b. The basic physiology of placental function. c. Histology of placenta ( note this for your interest only).Not core Placental Examination A one-minute examination of the placenta performed in the delivery room is generally recommended and satisfactory for the observations you will need to make. The findings are then usually entered into the delivery records and will serve as the basis for the care of the mother and her infant. A 1. Observe for: size, shape, consistency and completeness The presence of any accessory lobes, placental infarcts, hemorrhage and tumors should be noted. 2. Inspect the umbilical cord for: length, insertion, number of vessels (2 arteries and a vein) and presence of Wharton's jelly 3. The color, luster (shine) and odour of the fetal membranes should be evaluated B Note inspection and palpation should be combined. The placental and maternal surfaces should be palpated for missing cotyledons Missing placental tissue may indicate abnormal lobation or the type of placenta present viz. placenta accreta, placenta increta or placenta percreta. All or part of the placenta is retained in placenta accreta, placenta increta and placenta percreta. In these conditions, the placental tissues grow into the myometrium to lesser or greater depths. Manual exploration and the removal of retained placental tissue is necessary in these cases. The normal cord contains two arteries and one vein. During the placental examination, you should count the vessels in either the middle third of the cord or the fetal third of the cord, because the arteries are sometimes fused near the placenta and are therefore difficult to differentiate. Cross Section of Umbilical Cord EXAMINATION OF THE PLACENTA IN THE DELIVERY ROOM Normal Finding Assess PLACENTAL completeness Average Placental size Complete Normal Appearance Relevance All cotyledons present Diameter: about 22 cm Thickness: 2.0 to 2.5 cm Weight: about 470 g UMBILICAL CORD Cord length Include the fetal and maternal ends average 40 to 70 cm. Number of Vessels 3 (2arteries, 1 vein) Count the number of vessels at more than 5 cm from the placental end of the cord. Insertion Central MEMBRANES Smell Usually none 2 Fused layers ABNORMAL FINDINGS PLACENTA Placenta Grows into membranacea myometrium Hemorrhage and poor fetal outcomes Placenta accreta and placenta percreta Probable retained placenta, Increased incidence of postpartum infection and hemorrhage Abnormalities of SHAPE Multiple lobes bilobate, bipartite, succenturiate, accessory. Probable retained placental tissue. . MATERNAL FETAL SURFACE Placental infarcts Placental bleeding (e.g., abruption) Firm pale or gray areas Old infarcts P.I.H., S.L.E, Advanced maternal age Dark areas Fresh infarcts P.I.H., S.L.E. Advanced maternal age Clot, especially an adherent clot near placental centre, Distortion of placental shape Associated with abruption Fresh clot along the margin. No distortion of placental shape Marginal hematoma: If the clot is small, implies no significance PLACENTAL SIZE Thin placenta Less than 2 cm. Possible placental insufficiency with IUGR. Thick placenta More than 4 cm. Maternal diabetes Fetal hydrops Intrauterine fetal infection Incomplete, Retained placenta Missing bits of Bleeding (uterus can’t membrane/cotyledons contract). Infection FETAL PLACENTAL SURFACE Fetal anemia Pale fetal surface Anemia in newborn Fetal hydrops Severe Hemorrhage. circumvallete placenta. Thick ring of membranes Prematurity, Abruption, Multiparity. Early fetal loss Circummarginate Inner membrane placenta. ring thinner than outer. May be associated with an increase in fetal malformations. Fetus papyraceus and fetus compressus One or several nodules or thickenings Deceased twin May be associated with otherwise unexplained fetal demise Amnionic bands Delicate or robust bands of amnion Amputation of fetal parts Fetal death Short cord Less than 40 cm Poorly active fetus Down syndrome Decreased intelligence quotient Fetal malformations Myopathic and neuropathic disease Cord rupture, hemorrhage or stricture Breech or other fetal malpresentation Prolonged second stage of labor Abruption Uterine inversion Long cord More than 100 cm Fetal hyperkinesis Thromboses UMBILICAL CORD Thin cord and decreased amount of Wharton's jelly Narrow areas in the cord (normal cord diameter is 2.0 to 2.5 cm) Postmaturity and oligohydramnios Torsion and fetal death Edema Diffuse Hemolytic disease Prematurity Cesarean section Maternal preeclampsia Eclampsia Maternal diabetes mellitus Transient tachypnea of the newborn Idiopathic respiratory distress Focal Trisomy 18 syndrome Patent urachus Omphalocele Velamentous cord insertion Increased risk of fetal hemorrhage from the unprotected vessels, as well as vascular compression and thrombosis Advanced maternal age Diabetes mellitus Smoking Single umbilical artery Fetal malformations Cord knot Fetal compromise if the knot is tight Entanglement Fetal compromise, especially at delivery Abnormal number of vessels Expect two arteries, one vein If only one artery is present, up to nearly a 50 percent incidence of fetal anomalies Cord more prone to compression Other thromboses Clot in vessel(s) on cut section Fetal compromise Color Green Meconium staining Old blood from an earlier bleeding event Infection. MEMBRANES Smell Malodorous Possible infection Fecal odor: possibly Fusobacterium or Bacteroides infection Sweet odor: possibly Clostridium or Listeria infection Permission: American Academy of Family Physicians ANATOMY OF THE PLACENTA The amnion is a membranous sac which surrounds and protects the embryo. The amniotic cavity is roofed in by a single stratum of flattened, ectodermal cells, the amniotic ectoderm, and its floor consists of the prismatic ectoderm of the embryonic disk The Chorion is the outer lining which consists of two layers: an outer formed by the primitive ectoderm or trophoblast, and an inner by the somatic mesoderm; with this latter the amnion is in contact. The trophoblast is made up of an internal layer of cubical or prismatic cells, the cytotrophoblast or layer of Langhans, and an external layer of richly nucleated protoplasm devoid of cell boundaries, the syncytiotrophoblast. It undergoes rapid proliferation and forms numerous processes, the chorionic villi, which invade and destroy the uterine decidua and at the same time absorb from it nutritive materials for the growth of the embryo. The umbilical cord attaches the fetus to the placenta; its length at full time, as a rule, is about equal to the length of the fetus, i.e., about 50 cm., but it may be greatly diminished or increased. The normal cord contains two arteries and one vein. On section, the placenta presents a soft, spongy appearance, caused by the greatly branched villi; surrounding them is a varying amount of maternal blood giving the dark red color to the placenta. Many of the larger villi extend from the chorionic to the decidual surface, while others are attached to the septa which separate the cotyledons; but the great majority of the villi hang free in the intervillous space. Development of Placenta and membranes i Early formation of Allantois and differentiation of yolk stalk ii Later stage of development with constriction of yolk sac iii Expansion of amnion iv Development of umbilical cord Placental Function The placenta is a multifaceted organ that plays critical roles in maintaining and protecting the developing fetus. It serves three important functions: 1. Nutrient transfer from the mother to the fetus and waste secretion from the fetus to the mother. 2. Acts as a barrier for the fetus against pathogens and the maternal immune system. 3. An active endocrine organ. Placental insufficiency / intrauterine growth restriction (IUGR) is a major cause of increased perinatal morbidity and mortality in humans, and has recently been tied to the predisposition of adult onset of diabetes, hypertension, stroke and coronary heart disease