OB Flashcards
(147 cards)
What is alpha fetoprotein? When is measured?
Protein produced in the yolk sac, GI tract, liver. Measured at 15-20 weeks gestation (ideally between 16-18 weeks) to screen for fetal anomalies
AFP is mostly elevated in what conditions?
Screen for neural tube defects (anencephaly, spina bifida). Ventral wall defects (gastroschisis, omphalocele) and multiple gestation. Less commonly increased MSAFP can be seen in fetal congenital nephrosis and benign uropathy. MSAFP is decreased in aneuploidies
Down syndrome hormone profile
Low AFP, low estriol, elevated bHCG and inhibin A
Trisomy 18 hormone profile
Low AFP, very low estriol, very low bHCG and normal inhibin A
How does rhogam work
Anti D immunoglobulins given to the mother. They take out any fetal RhD positive erythrocytes that have entered the maternal blood stream before the mom’s immune system can get sensitized to it. Rho D Ig is composed of IgG antibodies and can cross the placenta and in rare cases can cause the baby to have positive direct antiglobulin test due to sensitization of fetal cells from mothers who have received multiple doses of RhoD immune globlulin.
ABO incompatibility often occurs when?
O moms have group A or group B babies but the degree of hemolytic diseae is much less severe compared to RH incomability
ABO incompatbility can occur during the first pregnancy because?
both A and B antigens are found in food and bacteria in the environment. These can produce various degrees of antibodies in group O individuals.
Hormone responsible for milk synthesis and hormone responsible for milk letdown
Prolactin responsible for synthesis and oxytocin - contraction of lactiferous glands and ducts resulting in the excretion of milk. Note that during pregnancy, estrogen and progesterone interfere with prolactin. Upon delivery, estrogen and progesterone decrease sharply, allowing prolactin to work
Bromocriptine is?
Dopamine agonist that acts by inhibiting prolactin secretion by the anterior pituitary thus suppressing lactation.
Causes of fetal growth restriction (
Asymmetric (maternal factors) - vascular disease (htn, PEC, diabetes), antiphospholipid antibody syndrome, autoimmune disease (SLE), cyanotic cardiac disease, substance abuse (tobacco, alcohol, cocaine). Symmetric (fetal factors) - genetic disorders, congental heart disease, intrauterine infection
IUGR predisposes child to
obesity, cognitive delay in childhood, diabetes, coronary artery disease, stroke
Sheehan Syndrome
Anterior pituitary infarction. Occurs when there is massive post partum hemorrhage and hypotension leading to hypoperfusion of the anterior pituitary gland. Can also occur after a normal delivery and may lead to deficiency of any of the anterior pituitary hormones (LH, FSH, TSH, ACTH, growth hormone, prolactin)
Sheehan syndrome initial prsentation
initial failure of postpartum lactation due to prolactin deficiency. Can also develop, persistent hypotension, amenorrhea, loss of sexual hair, weight loss, lethargy
Chorioamniotis diagnosed based on
Maternal fever, maternal and fetal tachycardia, uterine tenderness
Placental abruption symptoms/signs
80% present with bleeding but 10-20% don’t have bleeding. No bleeding does not rule out. abdominal or back pain, high-frequency, low-intensity contractions. Presents with uterine stiffness (blood is uterotonic). Significant abruption compromises fetal oxygenation so will show nonreassuring fetal heart rate tracings (variable declerations, late decelerations, or fetal bradycardia). Does not improve with intrauterine resuscitation measures.
Greatest risk factor for placental abruption
Maternal hypertension, PEC/eclampsia, other risk factors include cocaine or tobacco abuse, abdominal trauma, excessive uterine distension, previous placenta abruption
Tx for placental abruption
Unstable maternal VS or non reassuring fetal HR tracing => emergency section. If stable maternal VS, ok FHR tracing, >= 34 weeks, no placenta previa = trial of vaginal delivery
Dx of placental abruption
Mostly by clinical presentation but also use U/S to rule out placenta previa. Side note: maternal fever and leukocytosis are not typically a/w placental abruption
What is the Kleihauer-Batke test?
Used to measure the amount of fetal hemoglobin transferred into the maternal bloodstream.
Kleihauer-Batke test is performed on what women?
Rh negative women with Rh positive fetus to determine the dose of Rh immnoglobulin that should be given to the mother.
Pelvic exam is contraindicated in patients with antepartum hemorrhage until
Placenta previa is ruled out
Placenta previa clinical ppt?
usually PAINLESS Vaginal bleeding in third trimester with 2/3 cases presenting at 30 weeks gestation.
Management of placenta previa?
Depends on the severity of the bleeding and age of the pregnancy. If fetus at term, mother stable, scheduled section. If pregnancy is not yet term and fetus is stable,c lose monitoring. At 36 weeks do amniocentesis to assess lung maturity. If lungs are mature, elective C section. Complete placenta previa requires delivery by section.
Prolonged rupture of membranes
> 18 hours of rupture