Abnormalities of Pregnancy 1 Flashcards

Describe and recognize common abnormal processes that affect pregnancy outcome.

1
Q

List the common causes for iatrogenic preterm birth.

A
  • Placenta previa
  • Vasa previa
  • Placental abruption
  • Fetal growth restriction
  • Preeclampsia
  • Rh alloimmunization (previously called isoimmunization)
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2
Q

How common is placenta previa, and what is its definition?

A
  • 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
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3
Q

What are some common risk factors that can lead to placenta previa?

A
  • Prior cesarean delivery
  • Multiparity
  • Advanced maternal age
  • Prior placenta previa
  • Smoking
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4
Q

What are the goals for diagnosis in placenta previa? What are some possible complications?

A
  • Goals of diagnosis
    • Awareness: pelvic rest
    • Planned cesarean section at 37 weeks gestation
    • Expectant management and administration of antenatal corticosteroids if appropriate
  • Possible complications
    • Placenta accreta
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5
Q

What is the definition of vasa previa? What are some possible mechanisms?

A
  • Defintion: Vaginal bleeding that is arising from fetal vessels (fetal blood)
  • Possible contributing mechanisms: Remains unknown
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6
Q

What are the goals of diagnosis in vasa previa?

A
  • 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)
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7
Q

What is the definition of placental abruption? What are some possible contributing mechanisms?

A
  • 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)
  • Possible contributing mechanisms
    • Remains unknown
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8
Q

What are some risk factors that can lead to placental abruption?

A
  • Hypertension
  • Prior placental abruption
  • Abdominal trauma
  • Smoking
  • Cocaine
  • Uterine anomalies or submucosal fibroids
  • PPROM
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9
Q

What is the management of placental abruption?

A
  • Administration of antenatal corticosteroids if appropriate
  • Delivery based upon maternal and fetal status
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10
Q

What is the definition of fetal growth restriction?

A

Fetus who is less than 10th percentile for a given gestational age

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11
Q

What are some common causes of fetal growth restriction?

A
  • Fetal
    • Aneuploidy
    • Fetal anomalies
    • Infection (TORCH)
    • Multiple gestation
  • Uteroplacental
    • Uteroplacental insufficiency as a result of processes such as:
      • chronic hypertension
      • preeclampsia
      • chronic abruption
  • Maternal
    • Malnutrition
    • Illicit drug use
    • Smoking
    • Maternal medical conditions:
      • cyanotic heart disease
      • anemia
      • chronic pulmonary disease
      • poorly controlled hyperthyroidism
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12
Q

What is involved in the diagnosis of fetal growth restriction and what are the goals?

A
  • 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
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13
Q

What is the definition of preeclampsia? What are some possible contributing mechanisms?

A
  • Typically only severe preeclampsia requires preterm delivery
  • Definition: New-onset hypertension and proteinuria
    • Edema no longer technically part of definition as it is common in routine pregnancies
    • 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)
  • Possible contributing mechanisms
    • Poor trophoblast remodeling of maternal spiral arterioles
    • Possible increased production of sFlt-1 along with other anti-angiogenesis proteins
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14
Q

What is the management of preeclampsia?

A
  • 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
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15
Q

What is the definition of Rh alloimmunization?

A
  • 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)
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16
Q

What are the steps in prevention of Rh alloimmunization?

A
  • Administration of Rh immune globulin to all pregnant women who are Rh negative (unless certain that father is Rh negative)
    • Routine
      • 28 weeks gestation
      • 40 weeks or after delivery
    • Also with any other concern for breakage in fetomaternal barrier
      • First trimester bleeding/miscarriage
      • Ectopic pregnancy
      • Abdominal trauma with concern for abruption
      • Abruption
      • Previa
      • Amniocentesis/CVS
  • One 300 ug dose covers 30 cc whole fetal blood (or 15 cc fetal RBCs)
17
Q

What are the management strategies for Rh alloimunization?

A
  • Paternal genotype
  • Fetal antigen status
  • Serial antibody titers
  • Fetal middle cerebral artery doppler peak-systolic velocity indices
  • Periumbilical cord blood sampling with intrauterine transfusion