Ans. a Twins. (Ref. Dutta, Obstetrics, 4th/pg.221)D/d of Large placenta/hyperplacentosis:# Twin pregnancy# Hydrops fetalis# Diabetes in pregnancy# IUGRHUMAN PLACENTA# It is Discoid, Deciduate and Haemchorial.# It develops from--- foetal (4/5th)--chorionic frondosum and- maternal (l/5th)--decidua basalis.# Its development begins at 6th week of gestation and is completed by 12th week.Q# Its weight is 500 gms and weight of blood in it is 500 ml.# Fetal blood flow through placenta = 400 ml/min# Decidua basalis retains its characteristic appearance till term and becomes the maternal portion of placenta.# Line of separation of placenta after birth of the baby is through decidua spongiosum.# Fetal surface has attachment of umbilical cord with ramification of umbilical vessels and aminon.# Only decidua basalis and blood in the inter villou space are of maternal origin.# Maternal surface has shaggy looks with cotyledons.# Placentome = fetal cotyledon.# Villi are the functional units of placenta. Umbilical arteryUmbilical veinO2 saturation50-60%70-80%pO2 (mm Hg)20-2530-40# Placental calcification is a feature of postmaturity.# Signs of Placental aging:- Appearance of syncytial knots.- Decreased stromal tissue including Hofbauer cells.- Partial deficiency of Langhan's cells.- Thinning of basement membrane layer of foetal endothelium.# Most common tumour of placenta is choriohaemangioma.QDiscriptionDiscriptionType of placentaPlacenta with umbilical cord attached to its marginPlacenta with chorionic plate smaller than basal platePlacenta associated with increased rate of prematurityPlacenta with accessory lobes in the membranes away from main body of placenta, connected by large vessels to main body which if it goes to cervix causes formation of "Vasa previa"--a vital cause of bleeding of fetal originBattledore placentaCircumvallate placenta.Circumvallate placenta.Succenturiate placenta.Placenta with functioning villi covering all foetal membranesPlacenta with central portion missingMembranous placenta.Fenestrated placenta.