| Placental completeness | Intact, complete | All cotyledons present | No apparent retained placental fragments |
| No velamentous vessels; vessels taper to periphery of placenta |
| Incomplete | Cotyledons missing | Probable retained placental tissue (e.g., in cases of placenta accreta) |
| Velamentous vessels present (see Figure 6) | Probable retained placental tissue (e.g., in cases of retained succenturiate lobe of placenta) |
| Retained tissue is associated with postpartum hemorrhage and infection |
| Placental size | Normal | Diameter: about 22 cm | |
| Thickness: 2.0 to 2.5 cm |
| Weight: about 470 g (roughly 1 lb) |
| Thin placenta | Less than 2 cm | Possible placental insufficiency with intrauterine growth retardation |
| Placenta membranacea (rare condition in which the placenta is abnormally thin and spread out over a large area of the uterine wall; associated with bleeding and poor fetal outcome) |
| Thick placenta | More than 4 cm | Maternal diabetes mellitus |
| Fetal hydrops |
| Intrauterine fetal infections |
| Abnormalities of shape | Multiple lobes (bilobate, bipartite, succenturiate, accessory) | See Figures 1 and 2 | Probable retained placenta, with surgical removal required |
| Increased incidence of postpartum infection and hemorrhage |
| Placenta membranacea | | Hemorrhage and poor fetal outcomes |
| Placenta accreta and placenta percreta | | Probable retained placenta, with surgical removal required |
| | Increased incidence of postpartum infection and hemorrhage |
| Abnormalities of the maternal placental surface and substance | Placental infarcts | Firm pale or gray areas | Old infarcts |
| Pregnancy-induced hypertension |
| Systemic lupus erythematosus |
| Advanced maternal age |
| Dark areas | Fresh infarcts |
| Pregnancy-induced hypertension |
| Systemic lupus erythematosus |
| Advanced maternal age |
| Fibrin deposition | Firm gray areas | No clinical significance unless extensive, in which case there may be placental insufficiency with intrauterine growth retardation or other poor fetal outcome |
| Placental bleeding (e.g., abruption) | Clot, especially an adherent clot toward the center of the placenta, with distortion of placental shape | Associated with abruption |
| Fresh clot located along the margin, with no distortion of placental shape | Marginal hematoma: no clinical significance if the clot is small |
| Chorioangioma | Fleshy, dark red | If small, probably of no clinical significance |
| If large, may be associated with fetal hydrops |
| Choriocarcinoma | Resembles a fresh infarct | Very rare with a normal gestation |
| Hydatidiform mole | Grape-like cluster of edematous villi | Very rare with a normal gestation |
| Abnormalities of the fetal placental surface | Fetal anemia | Pale fetal surface | Anemia in newborn |
| Fetal hydrops |
| Hemorrhage requiring transfusion |
| Circumvallate placenta | Thick ring of membranes (see Figure 3) | Prematurity |
| Prenatal bleeding |
| Abruption |
| Multiparity |
| Early fluid loss |
| Circummarginate placenta | Inner membrane ring thinner than circumvallete placenta (see Figure 4) | Probably of no clinical significance, but may be associated with an increase in fetal malformations |
| Amnion nodosum | Multiple tiny white, gray or yellow nodules (see Figure 5) | Oligohydramnios |
| Renal agenesis |
| Pulmonary hypoplasia |
| Squamous metaplasia | Multiple tiny white, gray or yellow nodules especially around the cord insertion | Common and probably of no clinical significance |
| 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 |
| Abnormalities of the umbilical cord | Cord length | Measure cord length and include the fetal and maternal ends (normal length: about 40 to 70 cm) | |
| Short cord | Less than 40 cm | Poorly active fetus |
| Down syndrome |
| Werdnig-Hoffmann disease |
| 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 |
| | Increased risk of fetal entanglement |
| | Increased risk of torsion and knots |
| | Thromboses |
| Thin cord and decreased amount of Wharton's jelly | Narrow areas in the cord (normal cord has a relatively uniform diameter of 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 |
| Necrotizing funisitis | Distinctive segmental resemblance to a barber's pole | Syphilis and other acute, subacute and chronic infections |
| Possible swelling, necrosis, thrombosis and calcifications |
| Velamentous cord insertion | See Figure 6 | 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 |
| Count the number of vessels at more than 5 cm from the placental end of the cord | Cord more prone to compression |
| Other thromboses | Clot in vessel(s) on cut section | Fetal compromise |
| Amnionic web at the base of the cord | Fetal compromise |
| Abnormalities of the membranes | Color | Green | Meconium staining |
| Old blood from an earlier bleeding event |
| Infection (myeloperoxidase in leukocytes) |
| Smell | Malodorous | Possible infection |
| Fecal odor: possibly Fusobacterium or Bacteroides infection |
| Sweet odor: possibly Clostridium or Listeria infection |