Clinical: Placental Insufficiency Flashcards
Size of mature placenta
- 20 cm diameter
- 2-3 cm thick
- Weight 1/7th of fetus
- Villi surface area 11-14 m2
Describe the shape of the mature placenta
Discoid (chorionic plate = decidual plate)
2 components of the fetal surface
Amnion and chorion, fetal vessels
2 components of the maternal surface of the mature placenta
Lobes/cotyledons and placental septae
4 causes of abnormal placentation
- Maternal hyper-coagulability
- Incomplete invasion of spiral arteries
- Hydatidiform mole
- Choriocarcinoma
4 potential consequences of maternal hyper-coagulability
- Blood clots in the lacunae
- Poor diffusion
- Fetal death
- Miscarriage (often recurrent)
5 potential consequences of incomplete invasion of spiral arteries (leading to abnormal placentation)
- Placental ischemia
- Production of ischemic/necrotic factors
- Continued high resistance system
- Fetal growth retardation
- Pre-eclampsia
3 ischemic/necrotic factors produced due to incomplete invasion of spiral arteries
- Soluble fms-related tyrosine kinase 1
- Soluble endoglin
- Decreased PIGF
7 potential consequences of pre-eclampsia
- HTN
- Proteinuria
- Edema
- Fetal growth retardation
- Cerebral edema – fitting/seizures
- Still-birth
- Maternal death
How to diagnose defective placentation
Uterine artery Doppler waveforms
- High resistance to maternal circulation characterized by notching
Define intra-uterine growth retardation/restriction (IUGR)
- Fetal growth failing (arising from maternal, placental, or fetal origins)
- Birth weight lower than expected in the suitable gestational week
Dynamic definition of IUGR
Delay of the growth of the fetus estimated as a decrease of 25 centiles in the measure of the abdominal circumference, according to the standard curve at the gestational age, and in subsequent echographic evaluations performed at least every 2 weeks
2 classes of IUGR
Asymmetrical
Symmetrical
Define asymmetrical IUGR
Late onset (around 30 weeks) where abdominal growth is more affectedthan head circumference
Define symmetrical IUGR
Early onset (beginning of second trimester) where there is proportional lagging of the head circumference, abdominal circumference, and long bone growth
3 fetal risk factors for IUGR
- Chromosomal abnormalities
- Structural malformations (especially cardiac malformations)
- Fetal infections
3 chromosomal abnormalities that have a risk for IUGR
- Triploidy
- Trisomy 13 and 18
4 fetal infections that have a risk for IUGR
- TORCH
- Parvovirus B19
- Syphilis
- Listeriosis
5 placental risk factors for IUGR
- Abnormalities of the placentation
- Acute atherosis
- Obliteration of small muscular arteries of the tertiary villi
- Confined placental mosaicism
- Chorioangioma
Abnormality of the placentation that may cause IUGR
Reduction of number of thin-walled, distended uteroplacental vessels
10 maternal risk factors for IUGR
- Low socioeconomic status
- Chronic maternal under nutrition
- Malnutrition (anorexia nervosa, bulimia)
- CVD (cardiac failures, HTN, pre-eclampsia)
- Gestroenteric diseases (chronic enteritis, malabsorption)
- Pulmonary diseasees (CF, asthma, resp failure)
- Renal diseases
- Anemia
- Alcohol and drug abuse, smoking
- Uterine abnormalities (fibroids, uterine malformations)
Approx 25% of women with unilateral persistant notch and 50% of those with bilateral notch on doppler exam of uterine arteries will have what 2 conditions?
- IUGR fetus
- Develop pre-eclampsia
- Experience both
Doppler exam findings on umbilical arteries for fetuses with IUGR
Reduced blood flow pattern during diastole
5 signs of fetal compromise
- Gradually increasing resistance to blood flow in umbilical arteries
- End distolic component may disappear or may reverse
- Redistribution of blood flow occurs
- Brain, heart and adrenal glands preferentially perfused
- MCA blood flow increases
Define brain sparing
Cerebroplacental ratio is below 2SD prior to abnormal CTG recordings about a couple days to 2 weeks
Condition that brain sparing phenomenon is assocaited with
Fetal hypoxia
NOTE: When resistance in MCA begins to rise, cerebral edema occurs
7 tests of placental function
- Maternal weight
- Uterine growth - fundal height
- Fetal body movements
- Fetal growth (US)
- Fetal activity (biophysical profile, non-stress test)
- Color doppler studies
- Placental biochemical tests
Most important indication of placental function
Fetal well-being (i.e. “kick count” or how long it takes for the fetus to move 10 times)
2 methods of assessing fetal activity
- Non-stress test (Cardiotocography)
- Biophysical profile
Describe the non-stress test
Continuous record of FHR over a period of 30 min or more. Includes recording of changes in FHR variability (from beat to beat) in association with fetal movements and uterine contractions
Describe the biophysical profile
A score based on real time ultrasound observation of fetal breathing, gross body movements, tone and amniotic fluid volume
Define hydatidiform mole
Benign trophoblastic disease with overactive trophoblast/reduced resistance.
Accumulation in villi before circulation –> distension/swelling –> fetus dies and is resorbed
Define still birth
Dead fetuses or newborns weighing >500 gm or >20 weeks gestation
4 signs of still birth
- Absence of uterine growth
- Loss of fetal movement
- Absence of fetal heart
- Disappearance of the signs & symptoms of pregnancy
2 x-ray findings of still birth/IUFD
- Spalding’s sign
- Robert’s sign
4 fetal causes of still birth (IUFD) (25 - 40%)
- Chromosomal anomalies
- Birth defects
- Non-immune hydrops
- Infections
7 placental causes of IUFD (still birth) (25 - 35%)
- Abruption
- Cord accidents
- Placental insufficiency
- Intrapartum asphyxia
- Placental previa
- Twin to twin transfusion S
- Chorioamnionitis
14 maternal causes of IUFD (still birth) (5 - 10%)
- Antiphospholipid antibody
- DM
- HPT
- Trauma
- Abnormal labor
- Sepsis
- Acidosis/Hypoxia
- Uterine rupture
- Postterm pregnancy
- Drugs
- Thrombophilia
- Cyanotic heart disease
- Epilepsy
- Severe anemia
6 potential aspects of family history for still birth (IUFD)
- Recurrent abortions
- VTE/PE
- Congenital anomalies
- Abnormal karyotype
- Hereditary conditions
- Developmental delay
10 maternal medical conditions that may be found in a history for IUFD (still birth)
- VTE/PE
- DM
- HPT
- Thrombophilia
- SLE
- Autoimmune disease
- Severe anemia
- Epilepsy
- Consanguinity
- Heart disease
6 potential findings of past OB history for IUFD (still birth)
- Baby with congenital anomaly/hereditary condition
- IUGR
- Gestational HPT with adverse sequelae
- Placental abruption
- IUFD
- Recurrent abortion
9 potential findings of current pregnancy when taking history for IUFD (still birth)
- Maternal age
- Gestational age at fetal death
- HPT
- DM/gestational D
- Smoking, alcohol, or drug abuse
- Abdominal trauma
- Cholestasis
- Placanetal abruption
- PROM or prelabor SROM
8 potential placental/cord complications when taking history for IUFD (still birth)
- Large or small placenta
- Hematoma
- Edema
- Large infarcts
- Abnormalities in structure, length or insertion of the umbilical cord
- Cord prolapse
- Cord knots
- Placental tumors
6 placental investigatoins in event of IUFD
- Chorionocity of placenta in twins
- Cord thrombosis or knots
- Infarcts, thrombosis, abruption
- Vascular malformations
- Signs of infectoin
- Bacterial culture for E coli, Listeria, gp B strep
7 places specimen for karyotype fetal investigation can be taken
- Cord blood
- Intracardiac blood
- Body fluid
- Skin
- Spleen
- Placental wedge
- Amniotic fluid
Complication of IUFD
Hypofibrinogenemia
3 abnormal placental invasions
- Placenta accreta
- Placenta increta
- Placenta percreta
Define placenta accreta
Chorionic villi attach to the myometrial cells
Define placenta increta
Placenta penetrates the myometrium
Define placenta percreta
Placenta penetrates through the serosal surface
3 cancers that may cause placental metastases, although very rare (immunoprotective effect)
- Malignant melanoma
- Breast cancer
- Leukemias
