Abnormalities of Pregnancy 1 Flashcards
Describe and recognize common abnormal processes that affect pregnancy outcome.
List the common causes for iatrogenic preterm birth.
- Placenta previa
- Vasa previa
- Placental abruption
- Fetal growth restriction
- Preeclampsia
- Rh alloimmunization (previously called isoimmunization)
How common is placenta previa, and what is its definition?
- Accounts for 20% of third-trimester bleeding
- Definition: Implantation of placenta in location where it covers cervical os characterized by painless bright red vaginal bleeding
What are some common risk factors that can lead to placenta previa?
- Prior cesarean delivery
- Multiparity
- Advanced maternal age
- Prior placenta previa
- Smoking
What are the goals for diagnosis in placenta previa? What are some possible complications?
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Goals of diagnosis
- Awareness: pelvic rest
- Planned cesarean section at 37 weeks gestation
- Expectant management and administration of antenatal corticosteroids if appropriate
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Possible complications
- Placenta accreta
What is the definition of vasa previa? What are some possible mechanisms?
- Defintion: Vaginal bleeding that is arising from fetal vessels (fetal blood)
- Possible contributing mechanisms: Remains unknown
What are the goals of diagnosis in vasa previa?
- Technically, can do an Apt test (alkaline solution to blood à fetal blood cells are resistant to lysis, blood should remain red)
- Practically, no time to do Apt test and need to deliver rapidly (only takes minutes for fetus to bleed out its entire blood volume)
What is the definition of placental abruption? What are some possible contributing mechanisms?
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Definition: Premature separation of the placenta from the uterine wall and most typically characterized by vaginal bleeding in the presence of uterine contractions
- Vaginal bleeding may not always be evident (concealed bleeding behind the placenta)
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Possible contributing mechanisms
- Remains unknown
What are some risk factors that can lead to placental abruption?
- Hypertension
- Prior placental abruption
- Abdominal trauma
- Smoking
- Cocaine
- Uterine anomalies or submucosal fibroids
- PPROM
What is the management of placental abruption?
- Administration of antenatal corticosteroids if appropriate
- Delivery based upon maternal and fetal status
What is the definition of fetal growth restriction?
Fetus who is less than 10th percentile for a given gestational age
What are some common causes of fetal growth restriction?
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Fetal
- Aneuploidy
- Fetal anomalies
- Infection (TORCH)
- Multiple gestation
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Uteroplacental
- Uteroplacental insufficiency as a result of processes such as:
- chronic hypertension
- preeclampsia
- chronic abruption
- Uteroplacental insufficiency as a result of processes such as:
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Maternal
- Malnutrition
- Illicit drug use
- Smoking
- Maternal medical conditions:
- cyanotic heart disease
- anemia
- chronic pulmonary disease
- poorly controlled hyperthyroidism
What is involved in the diagnosis of fetal growth restriction and what are the goals?
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Diagnosis
- Suspected size<dates></dates>
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Goals of diagnosis
- Counseling parents about prognosis and if applicable, options regarding pregnancy management
- Institution of appropriate antenatal surveillance
- Administration of antenatal corticosteroids if appropriate
What is the definition of preeclampsia? What are some possible contributing mechanisms?
- Typically only severe preeclampsia requires preterm delivery
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Definition: New-onset hypertension and proteinuria
- Edema no longer technically part of definition as it is common in routine pregnancies
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Severe preeclampsia
- BP > 160/110 on two occasions 6 hours apart
- 24-hr urine protein > 5 g
- Maternal symptoms: Headache, visual changes, epigastric/RUQ pain
- Hepatic injury/failure
- Renal dysfunction/failure
- Pulmonary edema
- Coagulopathy
- HELLP syndrome (hemolysis, elevated liver enzymes, low platelets)
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Possible contributing mechanisms
- Poor trophoblast remodeling of maternal spiral arterioles
- Possible increased production of sFlt-1 along with other anti-angiogenesis proteins
What is the management of preeclampsia?
- Definitive therapy → delivery regardless of gestational age
- Expectant management if mild (and preterm) or if severe disease that is stable
- MgSO4 during intrapartum course and first 24 hours post-partum
What is the definition of Rh alloimmunization?
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Definition: Exposure of Rh negative mother to Rh positive fetal blood where she has produced antibodies against D antigen
- Antibodies result in hemolytic disease of fetus/newborn in subsequent pregnancy
- Alloimmunization can also occur with other maternal IgG antibodies against RBC antigens (e.g. Kell, Duffy, Kidd)