Placental Pathology AnS 536 Spring 2016

The Placenta The placenta is an endocrine organ, a site of synthesis, and selective transport of hormones and neurotransmitters. In addition, the placenta forms a barrier to toxins and infective organisms. Most of the known cause cases of stillbirths are caused by placental lesions/ abnormalities, then infections, and then umbilical cord abnormalities.

Placental Pathology There are some situations when pathologists are more inclined to interpret placental messages  Abortion  Fetal malformation  Intrapartum hypoxia  Placental Lesions  Complicated twin pregnancy  Prematurity  Intrauterine growth restrictions Pre-eclampsia  Intrauterine death  Infection Chorionic villous inflammation Chorioamnionitis

Abortion Estimated 50% of all conceptions are thought to end in abortion This is the body’s corrective response to an embryonic defect  Defect in chorionic villi Due to a genetic abnormality  Tetraploidy, triploidy, or trisomy

Chorionic Villi

Placental Lesions Placental lesions are suggested to be associated with illness severity shortly after birth, and with a wide range of neonatal problems Maternal vascular underperfusion  Inadequate spiral artery muscling Fetal thrombotic vasculopathy  Thrombosis, recent or remote, in the umbilical cord, chorionic plate or stem villus vessels

Maternal Vascular Underperfusion Fetal Thrombotic Vasculopathy

Twin Pregnancy Very rarely a twin pregnancy identifies the newborns as “identical” Chorionic tissue in the membrane means that the twins live in separate cavities.  Rate of complications is low Lack of chorionic tissue in the dividing membrane signifies a monochorionic cavity which means fetal-fetal vascular connections are present.  Arteriovenous fistulas  Arterio-arterial anastomoses within the chorionic plate

Arterial-arterial anastomoses Legend: Arteries- blue and green Veins-red and yellow White star- large arterio- arterial anastomosis Blue stars-several arterio- venous anastomoses Green stars- veno-arterial anastomoses

Infection Ascending amniotic infection  Bacteria ascending from the vagina and infecting the fetal membranes specifically the amnion and chorion Neutrophilic infiltrates in the membranes, chorionic plate, and umbilical cord Increased hepatic granulopoiesis Ingested and aspirated granulocytes Formation of bronchus-associated lymphatic tissue in the lungs  Segmented neutrophilic granulocytes within the fetal alveoli

Prematurity Pre-eclampsia  Begins after 20 weeks of normal pregnancy  Terminated on the mother’s side  Can lead to HELLP Syndrome Destruction of red blood cells, elevated liver enzymes, and low platelet count  Placentae are below 5 th percentile for weight, size, and display circulatory abnormalities Reduces blood flow to the placenta Amniotic infection

Intrauterine Growth Restriction Live-born severely growth-restricted children are occasionally observed with placentae containing barely 30% functional tissue Causes  Malfunction in the nutritional supply line  A genetic condition  Toxins  Impaired maternal blood flow through the intervillous space  Impaired fetal blood flow through the cord and allantoic vessels or chorionic villi

Intrauterine Death 3-4 of 1000 pregnancies that have progressed to fetal viability will result in sudden infant death syndrome. Fetus has died from hypoxia, as either a single or repeated event  Premature abruptio  At autopsy, hypoxic hemorrhages are seen in the pleura, pericardium, and meninges Placental dysmaturity or placental maturation defect  Placentae are of normal size with a pale cut surface  This is due to defective formation of both the sinusoidal vessels in the terminal villi and the syncytiocapillary membranes

Real Life Example Pine Needle Abortion  Ponderosa pine needles Diterpene abietane acids Symptoms  Severe Illness after abortion  Weak calves and prone to respiratory problems  Retained placentae  Endometritis  Renal and neurological lesions

Decline in Perinatal Postmortem Examinations Examination of the placenta should be done in every pregnancy failure, in children who survive birth but have an unexplained low Apgar score, infection, or growth retardation. When babies enrolled in a trial do go on to die, parents are not always asked about doing a postmortem examination. Reasons as to why a PM does not occur.  Prematurity  Lower birth weight  Specific diagnosis ie. Birth asphyxia

Professional Views on PM In general, the sample saw the importance of the PM as being strongly related to the cause of death; whereas only 31% felt that they were very important when the cause of death was extreme prematurity, when the cause of death was congenital anomaly, 94%, or an indeterminate cause only 91% felt they were very important. 17% of the sample indicated that they do not approach families that are upset.

Parental Views on PM 45% of parents who did not permit a PM stated that they had not been approached. 81% of the responding parents had taken up the offer of a PM.  24% of these did so to contribute to research