Lecture 17 ABNORMALITIES OF PLACENTA AND UMBILICAL CORD

Lecture 17 ABNORMALITIES OF PLACENTA AND UMBILICAL CORD Prof. Vlad TICA, MD, Ph. D

PLACENTA: PHYSIOLOGY AND FUNCTION A. Fetus entirely dependent on placenta until birth B. Maternal and fetal blood kept separate by placental barrier C. Protects the infant from infection and harmful substances D. Acts as endocrine organ - makes hormones to maintain pregnancy E. Made of 12 -20 cotyledons

PLACENTA: PHYSIOLOGY AND FUNCTION F. Fetal blood transported to placenta via 2 umbilical arteries G. Umbilical arteries get smaller and become arterioles then villi H. Villi suspended in pools of maternal blood in the lacunae I. Fetal blood returns to fetus via umbilical vein

ABRUPTIO PLACENTAE 1. DEFINITION � Separation of the normally situated placenta from its uterine site of implantation after 20 weeks gestation, but before delivery of the placenta

ABRUPTIO PLACENTAE 2. PLACENTAL GRADES � Grade 0 - Patient asymptomatic. Small retroperitoneal clot seen after delivery � Grade 1 - Vaginal bleeding, may have abdominal tenderness or slight uterine tetany, mom and baby not in distress � Grade 2 - Uterine tenderness, tetany with / without evidence of bleeding, baby shows signs of distress � Grade 3 - Uterine tetany, severe bleeding may not be visible. Baby is dead. Mom often has coagulopathy

ABRUPTIO PLACENTAE

ABRUPTIO PLACENTAE 3. INCIDENCE � Varies from 1/55 to 1/250 cases � Incidence greater with increasing parity or history of abruption

ABRUPTIO PLACENTAE 4. ETIOLOGY � Unknown � Possibly begins with degenerative changes in the small arterioles that supply the intervillous spaces, resulting in thrombosis, degeneration of the decidua, and finally rupture of the vessel � Then tearing and bleeding in the inner layer of the endometrium and decidua basalis � Hematoma forms along with retroperitoneal clot, compresses adjacent placenta, causing local destruction � Further bleeding causes increased pressure behind the placenta which causes further separation

ABRUPTIO PLACENTAE 5. CONDITIONS ASSOCIATED WITH ABRUPTION: � Hypertension - 5 x higher � Trauma � Short umbilical cord � Polyhydramnios � IV cocaine use � Uterine anomalies

ABRUPTIO PLACENTAE 5. CONDITIONS ASSOCIATED WITH ABRUPTION: � OB history: 1. History of spontaneous abortions 2. Premature labor 3. Antepartum hemorrhage 4. Stillbirth / neonatal death 5. Parity > 7 - 6 x greater 6. History of abruption - 30 x greater 7. Cigarette smoking - decidual necrosis

ABRUPTIO PLACENTAE 6. SIGNS AND SYMPTOMS � Depends on type of abruption: � Mild c/o labor pains, may only have slight uterine irritability � May have no / only small amount of bleeding � Severe knife-like pain with board-like abdomen � May / may not see bleeding � Uterus could be tender at point of separation or may be generalized over entire abdomen

ABRUPTIO PLACENTAE

ABRUPTIO PLACENTAE 6. SIGNS AND SYMPTOMS � Depends on type of abruption: � Increased uterine distention - elevated fundal height � Bleeding may be minimal or diffuse. Can be port-wine, dark, or bright red � Symptoms are determined by amount of blood lost � Shock is severe � Fetal distress or death

ABRUPTIO PLACENTAE 7. DIAGNOSIS � Based on hystory, physical exam, lab values � NO analgesia / anesthesia until diagnosis confirmed � Vaginal bleeding with / without pain � Increased uterine tone, tenderness � Shock � Fetal distress � U/S for placental localization, position � Palpation of abdomen, measure fundal height � Confirm after delivery-inspect placenta

ABRUPTIO PLACENTAE

ABRUPTIO PLACENTAE 8. MATERNAL/ FETAL OUTCOME � Mortality rate < 1%; if undetected until fetal death, mortality rate is 10% � DIC - 30% � Renal failure from hypovolemia � Amniotic fluid embolus � Uterine rupture � Postpartum endometritis � Postpartum hemorrhage

ABRUPTIO PLACENTAE

ABRUPTIO PLACENTAE 9. MEDICAL MANAGEMENT � US to R/O placenta praevia � Bedrest (lateral position) � IV with large bore catheter � Type and crossmatch, CBC, platelet count, fibrinogen, bleeding time � Frequent vital signs � Assess for signs of shock - cold, clammy skin, pale, anxious, thirsty � Assess FHR and uterine activity

ABRUPTIO PLACENTAE 9. MEDICAL MANAGEMENT � Mark top of fundus (check to see if rising) � Observe for signs of vaginal bleeding � C/S for fetal distress, maternal blood loss or compromise, coagulopathy, poor labor progress � Strict I & O � Amniotomy to assess blood in fluid � Oxygen per mask � Avoid episiotomy � Be aware of postpartum hemorrhage

PLACENTA PRAEVIA 1. DEFINITION � Abnormally implanted placenta placed totally / partially in the lower segment of the uterus, rather than in the fundus � When the cervix begins to dilate and efface the placenta separates, allowing bleeding form the open vessels

PLACENTA PRAEVIA 2. CLASSIFICATION � Complete - internal os is completely covered by the placenta � Partial - a portion of the cervical os is covered by the placenta � Marginal - The edge of the placenta extends to the edge of the cervical os

PLACENTA PRAEVIA

PLACENTA PRAEVIA 3. INCIDENCE � Depends on which trimester pregnancy is in: � 2 nd trimester - 45 % in lower uterine segment � 3 rd trimester - 0. 5 to 1 % in lower uterine segment � Occurs more often in multiparas - 80 % � History of praevia - 12 x more likely � More common with history of abortions � C/S, molar pregnancies, fibroids, uterine surgery

PLACENTA PRAEVIA 4. ETIOLOGY � Unknown cause � It is thought that when the embryo is ready to implant and the decidua in the fundus is deficient, it will choose another spot lower in the uterine segment � Placentas are larger on the maternal side, cord often has marginal or vellamentous insertion � Suggests that the placenta was growing toward more favorable decidua

PLACENTA PRAEVIA 4. ETIOLOGY � Endometriosis after previous pregnancy � Uterine scars - abortions, C/S, molar pregnancy � Tumors altering contour of uterus � Close pregnancy spacing � Multiparity � Large placenta - in multiple gestations or erythroblastosis fetalis � High altitudes � Male fetus

PLACENTA PRAEVIA 5. DIAGNOSIS � Painless bright red vaginal bleeding - usually 1 st bleeding episode not before 30 weeks � Sometimes suspected with oblique / transverse lie � Diagnosed by U/S � 80 -90% - bleeding occurs without warning � Uterus non-tender - no rise in fundal height � Often occurs when sleeping � 1 st episode usually scant, each episode more � Shock � May deliver by C/S, if placenta covers cervix

PLACENTA PRAEVIA

PLACENTA PRAEVIA 6. MATERNAL AND FETAL OUTCOME � Mortality < 1%, morbidity = 20% � Most will have at least one significant hemorrhage, 25% will go into shock � Vaginal and cervical lacerations occur more often with vaginal delivery � Poor endometrium may contribute to placenta accreta � Fetal mortality 20% - prematurity, hypoxia, developmental disorders

PLACENTA PRAEVIA 7. MEDICAL MANAGEMENT � Depends on gestational age and severity of bleed: � Strict bedrest � IV - large bore catheter (16 gauge) � CBC, type & screen, platelet count, fibrinogen, bleeding time � If HCT < 30% → transfuse � No pelvic exams � Adequate hydration, accurate I & O

PLACENTA PRAEVIA 7. MEDICAL MANAGEMENT � Tocolysis for contractions � No douching or intercourse � Oxygen per mask � Serial U/S to check for placental placement, fluid level, fetal growth � C/S for large blood loss

PLACENTA ACCRETA 1. DEFINITION � a rare condition � all or part of placenta adherent to the myometrium � the normal spongy layer of decidua is absent / defective, therefore placental villi grows down through the endometrium into the myometrium

PLACENTA ACCRETA 2. TYPES � Accreta - villi extends too far into endometrium � Increta - villi invade into myometrium � Percreta - villi invade through myometrium to the serosa layer

PLACENTA ACCRETA 3. INCIDENCE � 1 / 7000

PLACENTA ACCRETA 4. PREDISPOSING FACTORS � Implantation over a previous C/S scar / other surgical scar in the uterine cavity � Previous curretagge � Prior history of endometritis / other endometrial trauma � High parity � Placenta previa sometimes precludes accreta

PLACENTA ACCRETA 5. SIGNS AND SYMPTOMS � None until delivery � Depends on depth, site of penetration, number of cotyledons involved � Partial accreta - some cotyledons may separate from the uterine wall, leaving open, bleeding vessels � The uterus is unable to contract because of the adherent placenta still within the uterine cavity � Profuse hemorrhage � Total accreta - tearing occurs when doctor tries to deliver placenta � Uterine inversion may occur

PLACENTA ACCRETA 6. DIAGNOSIS � Attempts to remove placenta reveals placental adherence

PLACENTA ACCRETA 7. OUTCOME � Hemorrhage � Shock � Uterine inversion � Hysterectomy

PLACENTA ACCRETA 8. TREATMENT � Large bore IV catheter � IV fluids, blood � US � Type and screen, CBC, platelet count, fibrinogen, bleeding time � Accurate I & O � Assess vital signs � D & C / hysterectomy

MULTILOBED PLACENTA BILOBED OR PLACENTA BILOBATA �Incidence: 2 -8% of placentas �Roughly equal size lobes are separated by a segment membranes �Umbilical cord may insert in either of the lobes or in velamentous fashion or in between the lobes

BILOBED PLACENTA

MULTILOBED PLACENTA PATHOGENESIS �Arise due to implantation in areas of decrease uterine perfusion �Example: �Lateral implantation in between anterior and posterior walls of the uterus with one lobe on the other and one on the posterior wall

MULTILOBED PLACENTA PATHOGENESIS �Other local factors leading to multilobulation: �Implantation over leiomyomas �Area of previous surgeries �In the cornu �Over the cervical os

CIRCUMVALLATE PLACENTA � The fetal surface of the placenta is exposed thorough a ring of chorion and amnion opening around the umbilical cord

CIRCUMVALLATE PLACENTA

SUCCENTURIATE PLACENTA � One or more accessory lobes of the villi have developed � Vessels from the major to the minor lobes are only supported by membrane � This increases the likelihood that the minor lobe(s) are may be retained during the third stage of labor

SUCCENTURIATE PLACENTA

COUVELAIRE UTERUS � Occurs in severe abruptio placenta, when blood collects in the uterine musculature beneath the uterine serosa, into connective tissue of the broad ligaments and even into the peritoneal cavity � Suturing, followed by administration of IV oxytocin, usually controls postpartum hemorrhage

COUVELAIRE UTERUS

ABNORMALITIES OF UMBILICAL CORD LENGTH �Mean length at term 55 -60 cm �Vascular occlusion by thrombi & true knots �Excessively short umbilical cords may be instruments in abruptio placenta & uterine inversion

SINGLE UMBILICAL ARTERY �Absence of one umbilical artery � 0. 85 % of all cords in singletons �About 30 % of all infants with only one umbilical artery are associated with congenital anomalies �Incidence: 18 -68 % �Infants with single-artery cord had � 18 % incidence of malformation � 34 % usually growth restricted � 17 % delivered preterm

SINGLE UMBILICAL ARTERY �Incidence is increase in newborn of women with: �DM �Epilepsy �Preeclampsia �Anterpartum age �Oligohydramnios �Hydramnios

BATTLEDORE PLACENTA � Cord inserted at / near the placental margin, rather than in the center

VELAMENTOUS INSERTION OF UMBILICAL CORD �An abnormal condition in which umbilical vessel does not insert into the placental mass but instead, traverse the fetal membrane before it inserts into the umbilical cord �Used to describe the condition in which the umbilical cord inserts on the chorioamniotic membranes rather than on the placental mass �Incidence: � 1. 1% in singleton pregnancies � 8. 7% in twin gestations �Spontaneous abortion � 33% between 9 th & 12 th wks AOG � 26 % between 13 th & 16 th

VASA PRAEVIA � Rare circumstance that may occur with velamentous insertion of the cord where umbilical vessels cross the internal os presenting ahead of the fetus � Requires a C/S

CORD ABNORMALITIES KNOTS �False knots �Result from kinking of the vessels to accommodate length of cord �True knots �Results from active fetal movement

CORD ABNORMALITIES TORSION �Result of fetal movement, cord normally becomes twisted �Marked torsion compromised fetal circulation LOOPS �Coiling of cord around the neck �Incidence of nuchal cord coil once → 21 %

CORD ABNORMALITIES HEMATOMA �Usually results from rupture of varix, usually of umbilical vein with effusion of blood into cord STRICTURE �Most but not all infants with cord stricture are stillborn �Associated with an extreme focal deficiency in Wharton’s jelly

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