Complications1-Table 1 Flashcards
What causes physiologic anemia?
Normal changes in ratio of plasma to RBC volume
How is physiologic anemia reflected?
As decreased Hct d/t the dilutional effect relative to each trimester
What are lab findings associated with Iron def anemia?
decreased Hct
What finding may accompany iron def anemia?
PICA
How is iron def anemia tx in preggo people?
Add an additional 60-80mg elemental iron daily
Why it taking folate a good idea?
Reduce the risk of NTD
How much dietary folate should be taken in?
400-800 mcg or 0.4-0.8mg
How much folate is in a prenatal vitamin?
1mg, 1000mcg
What would indicate a need to increase daily folate to 4mg or 4000mcg daily?
- multifetal gestation
- mom on anticonvulsants
- past hx of NTD pregnancy
What are hemoglobinopathies?
heterogeneous group of single gene disorders that include structural Hb variants
What is the Hb variant in sickle cell?
Hb A replaced with Hb S
What is sickle cell dz?
Homozygotes HbSS
Unstable sickled shape to RBC
Increased viscosity and hemolysis
Decreased oxygenation
What is sickle cell trait?
Heterozygoutes Hb AS
Asymptomatic
What is isoimmunization?
Formation of maternal antibodies, aka maternal alloimmunization
What leads to hemolytic dz of the newborn?
Binding of maternal antibodies to fetal RBC antigens
What is hemolytic dz of the newborn characterized by?
Hemolysis, bili relsease, anemia
How is the severity of hemolytic dz of the newborn determined?
- how much antibody was produces
- how strongly antibody binds to antigen
- ability of the fetus to replenish the destroyed RBC
What are the 4 major blood groups determined by?
Presence or absence of A & B RBC surface antigens
What makes group A?
has A antigen on RBCs & B antibody in plasma
What makes group B?
has B antigen on RBCs & A antibody in plasma
What makes group AB?
has both A & B antigens on RBCs but neither A nor B antibody in plasma
What makes group O?
has neither A nor B antigens on RBCs but both A & B antibodies in plasma
What is the 3rd antigen? When is it a problem?
Rh (rhesus) factor
Either present + or absent –
Positive is ok, negative is an issue unless both mom and dad are negative
What is the Rh system composed of?
A complex of 5 antigens
C, c, D, E, e
What is the most common antigen? Hint its part of the Rh- CDE system
Antigen D
What is the deal with antigen D?
Present: Rh-D positive
Absent: Rh-D negative
Why is antigen D important?
There is isoimmunization potential when an Rh-D negative woman is preggo with a fetus that is positive!
How much Rh-D blood is sufficient to cause isoimmunization?
How does this work?
Maternal antibodies pass to baby via placenta and cause an antibody response that destroys fetal RBC
Is isoimmunization with Rh a concern with 1st pregnant?
Not really- first pregnancy is exposure to mom and second is when the fetus is typically attacked
Gets progressively worse with each subsequent pregnancy
What are some events that might precipitate maternal exposure to fetal RBC?
—1st trimester bleeding: abortion, ectopic
—Placental abruption or previa( placenta is in front of the fetus)
—Childbirth, delivery of placenta
—Procedures: amniocentesis, external cephalic version
—Trauma (fetomaternal hemorrhage), parvo, CMV, toxo, syphilis
The most common cause of events is Rh and Parvo
What needs to be screened for for Parvo virus?
IgM & IgG specific antibodies B19
What indicates an acute infection and need to evaluate the fetus?
IgM
What does parvo virus do?
inhibits erythropoiesis d/t preference for erythroid progenitor cells
When is the greatest fetal risk?
How is parvo assessed and diagnosed in the fetus?
Doppler MCA- to look at flow of blood through MCA
US- to r/o hydrops
Amniotic fluid- look for fetal blood B19 DNA
What finding of Doppler of MCA would indicate no fetal anemia?
measure blood viscosity based on peak velocity of systolic flow (PSV) … less viscous with increased flow in no anemia… more viscous and slower flow indicated anemia
When is the peak incidence for hydrops?
4-6wks following maternal infection
How often should you do US/ MCA Doppler?
Weekly through 12 weeks post infection
When maternal antibodies enter and bind to fetal RBC, there is significant hemolysis and release of bilirubin. What can markedly elevated bili levels lead to?
Kernicterus- leads to permanent neuro symptoms and death
Why does anemia occur with hemolysis?
Fetus cannot produce enough RBC to replenish the lysed RBC
What is significant fetal anemia?
increased fetal hematopoiesis w/recruitment of alternate sites for RBC production
What happens with the fetal liver in significant fetal anemia?
Decreased oncotic pressure can lead to ascites, SQ edema, or pleural effusions
High output cardiac failure and myocardial ischemia
What can severe anemia result in?
Hydrops fetalis
What are the 2 types of hydrops fetalis?
Immune
Non-immune
What is immune hydrops?
complication of severe Rh incompatibility that results massive red blood cell destruction
What is non-immune hydrops?
NIHF) caused by disease or medical condition (cardiac anomaly) that disrupts body’s ability to manage fluid
What would you expect to see on an US with fetal echo in hydrops?
—Anomalies: fetus, umbilical cord, placenta (thickening)
—Amniotic fluid volume
—Pericardial & pleural effusions, ascites
How are the antibodies reported? ( maternal)
They are reported as antibody titer… 1:4, 1:16, etc
What is the significance of the titer?
The higher the titer, the more significant antibody response
What titer is associated with significant risk for fetal hemolytic dz or hydrops?
Critical titer- 1:8- 1:32
What does US with fetal echo asses?
fluid volume, anomalies and hydropic changes
What is included in an amniotic fluid assessment?
Bili levels, genetics, ID studies
what should happen is an intrauterine fetal transfusion if planned?
Percutaneous umbilical blood sampling…PUBS
What is the fetal Hct cutoff for transfusion in a highrisk perinatal center?
30%
What can you do to try to prevent isoimmunization?
Anti-D immune globulin to all Rh-D negative women routinely at 28weeks GA AND within 72 hours of delivery or in any circumstance where fetal and maternal blood may come in contact
What does anit-D immune globulin do?
Effectively presents sensitization to the D antigen
What does the kleihauer- Betke test do?
ID fetal erythrocytes in maternal circulation
ID appropriate dose of Rh immunoglobulin to be administered
What does an indirect Coombs determine?
If the pt has received sufficient antibody
Positive result = inadequate dosing
What is the most important cause of hemolytic dz of the fetus NOT associated with D antigen?
Kell antigens (K,k)
What results in Kell antigens?
Usually from a prior blood transfusion
What is the result of kell antigens?
Unique anemia…. results from destruction & suppression of hematopoietic precursor cells but hemolysis is limited
What is ABO hemolytic dz?
Maternal fetal incompatibility associated with mild fetal anemia and newborn hyperbilirubinemia
What is the chorion?
extraembryonic mesoderm on the inner surface creates by the proliferating trophoblast
When does the amnion develop?
When cells at the dorsal surface of the embryonic disk form a transparent membranous sac (sac will fill with the amniotic fluid!)
What are risks associated with multifetal gestation?
Preterm L&D, IUGR, hydramnios, preeclampsia, placental abruption, PP hemorrhage
What has increased the rate of twins?
ART/ovulatory induction
What is dizygotic twin gestation?
Fraternal- 2 separate ova fertilized by 2 separate sperm
What is monozygotic twin gestation?
Identical: division of fertilized ovum following conception
What are the 4 forms of monozygotic twin gestation?
1) Diamnionic/Dichorionic: each fetus is surrounded by an amnion & a chorion w/1 or 2 placentas
- -Division w/in 3 days fertilization
2) Diamnionic/Monochorionic: each fetus will be surrounded by an amnion but will have a single chorion
- -Division w/in 4-8 days fertilization
3) Monoamnionic/Monochorionic: twins will share a common sac as amnion & chorion have already developed
- -Division w/in 9-12 days fertilization
4) Conjoined twins: incomplete division
What are the risks associated with monochorionic gesation?
Twin-twin transfusion syndrome
Chord entanglement and fetal death
What is twin- twin transfusion syndrome?
arterial-venous anastomoses may form between fetuses & result in blood flow from one twin to the other
What happens to the different fetus in twin-twin syndrome?
1) Donor twin: may have impaired growth, anemia, hypovolemia: have ↓ urine output → oligohydramnios
2) recipient twin: HTN, polycythemia, HF, hypervolemic: have ↑ urine output → hydramnios
How can twin- twin transfusion syndrome be tx?
Laser ablation of anastomoses
How is cord entanglement tx?
hospitalize @ 26-28 wks & steroid administration
When is twin gestation suspected? How is it confirmed?
When uterine size > GA
US: confirm twin and chorion status
When should serial US begin to monitor for discordant growth?
q3-4 wks begin @ 16-18 wks GA
When do multifetal gestations tend to deliver?
Preterm
Twin: 35 wk
Triplets: 32 wks
Quads: 30 wks
When can twins be delivered vaginally?
Both are in the cephalic position
When do twins need to be delivered via c-section?
Both breech presentation
1st twin vertex and 2nd twin isn’t
1st twin is breeched
What complications are associated with multifetal deliveries?
Higher risk of cord prolapse, postpartum atony, and hemorrhage
What defines SGA?
Infant whose birth weight is
What defines IUGR?
Fetus whose weight
Why are IUGR associated with higher risk?
Lack adequate reserves to survive in utero, deal w/stress of labor, adapt to neonatal life
What is the pathology behind early onset IUGR?
commonly associated w/hereditary factors, immunologic issues, chronic maternal disease, fetal infection, multiple pregnancies
What is the pathology late early onset IUGR?
primarily related to decreased placental function & nutrient transport = uteroplacental insufficiency
What meds that mom takes can affect IUGR?
anticonvulsants, warfarin, folic acid antagonists
What viral infection in mom can cause IUGR?
CMV, rubella, varicella
What placental factors can lead to IUGR?
Defective trophoblastic invasion of placenta
Uterine abnormalities: limit placental growth & development,
Genetic composition of placenta
How is IUGR diagnosed?
FH-serial measurements, US, direct invasive studies
What is FH looking for to diagnose IUGR?
20 - 36 weeks EGA: height should increase approx 1 cm/week
discrepancy >2cm may indicate IUGR
What is the US examining?
Fetal biometric parameters (provide estimated growth rate of fetus)
- biparietal diameter (BPD)
- head circumference (HC)
- abdominal circumference (AC)
- femur length
What direct invasive studies are used to look for IUGR?
Amniocentesis
Doppler velocimetry
Doppler MCA flow
What does Doppler velocimetry asses? What is normal?
Fetal-placental circulation in umbilical artery - measure systolic/diastolic (S/D) ratio
—Normal ratio @ term = 1.8 to 2.0
What is the management goal of IUGR fetus?
Deliver the healthiest possible infant and the optimal time
What should staff be prepped for when delivering a fetus with IUGR?
hypoglycemia, RDS, hypothermia, hyperviscosity syndrome
What is hyperviscosity syndrome?
d/t fetus’s attempt to compensate for poor placental oxygen transfer by increasing Hct > 65% marked polycythemia s/p birth
What can hyperviscosity syndrome lead to?
multiorgan thrombosis, HF, hyperbilirubinemia
What is LGA?
Infant whose birth weight > 90% for GA based on population specifics
What is macrosomia?
Fetus weighing > 4,500 grams (9 lbs = 4,800 grams or 4.8 kg)
What maternal factors contribute to macrosomia?
Prior hx macrosomia Maternal prepregnancy weight, wt gain during pregnancy Multiparity GA > 40 weeks Ethnicity Maternal birth weight/height Maternal age
What risks are associated wit macrosomia for the fetus?
Shoulder dystocia, brachial plexus injury, fx clavicle
If mom obese or DM: hypoglycemia, prematurity, stillbirth, hypothermia
What risks are associated wit macrosomia for mom?
- Cesarean delivery
- Postpartum atony/hemorrhage
- Vaginal lacerations
How is macrosomia diagnosed?
Clinical estimation of fetal weight
- serial FH and Leopold
US
- fetal biometric parameters
What other conditions should you have on your DDX when dealing with macrosomia?
—Multifetal gestation
—Polyhydramnios
—Large placenta: molar IUP
—Large uterus: fibroids
How is macrosomia managed?
Non- GDM: no intervention, balance C section vs vaginal for safety
GDM: strict control of blood glucose and elective c section if EFW>4500
When is amniotic fluid produced?
Continuously after 16 wks
What is the role of amniotic fluid?
Protects against infection, trauma, umbilical cord compression, allows fetal mvmt and breathing
What is PROM? What is PPROM?
premature rupture of membranes before onset of labor; >37 weeks and is followed often by labor
Preterm PROM : occurs
What is the leading cause of neonate mobidity and mortality?
PPROM
When is it a PPROM previable subset?
20-25.6 weeks
What can cause P/PP ROM?
STDs around 32 weeks, subclinical infection
What are risk factors?
Prior PROM, short cervical length, prior preterm delivery, multifetal gestation, threatened AB, polyhydramnios, smokers
What are major risks for P/PP ROM?
intrauterine infection (chorioamnionitis), prolapsed cord, placental abruption
What is Chorioamnionitis?
Infection of membranes & amniotic fluid fever
Risk of sepsis leading to CP and CAN abnormalities in baby
What is the clinical presentation of Chorioamnionitis?
fever > 100.5F, maternal & fetal tachycardia, uterine tenderness, spontaneous/dysfunctional labor
mom describes gush of fluid or a steady leak
late sign: purulent cervical discharge
How is Chorioamnionitis diagnosed?
Clinically- labs are non-specific
Vaginal fluid = amniotic fluid until proven otherwise!!!
What test will rile in amniotic fluid?
—Nitrazine test: uses pH to distinguish amniotic fluid from urine or vaginal secretions
•Amniotic fluid: alkaline w/pH > 7.1, vaginal secretions: pH 4.5-6.0; urine: pH
What should you look for on US in choriamnionitis?
Large pockets vs very little fluid
How is Chorioamnionitis tx?
IV antibiotics, deliver promptly
How is term PROM managed?
Induction with oxytocin or expectant management… most will go into labor within 24hrs
When can you do expectant management for PROM?
If there are no other risk factors, just make sure to do serial eval for IU infections
What is done regardless of management for PROM?
GBS prophylaxis
What is the latency period?
Time from PROM to labor and is inversely related to GA
