OB Flashcards
Gestational age of PTL
20w - 36w6d
What is the leading cause of neonatal morbidity?
PTD
If a patient presents in PTL, what is the chance that she will have a PTD within 7 days?
10%
What are some risk factors for PTB?
h/o short CXL ?h/o LEEP or D&C VB UTI STI peridontal dz low BMI smoking drugs short interval pregnancy
If a patient has a h/o PTD, how much is her risk of a subsequent PTD increased?
1.5 - 2 fold
What is the definition of a short cervix?
<25mm (can intervene at <24w)
What is the definition of a short interval pregnancy?
<6 months, recommended to wait 18 months in between
What is fetal fibronectin?
chemical in the adhesion between the placenta and the uterine decidua
How is CXL measured?
TVUS, not too much pressure (falsely long), shortest of 3 measurements
When is use of FFN and CXL appropriate?
Only when patient has acute symptoms
When is tocolysis appropriate?
Use up to 48h to get BMZ and mag for FNP on board, only up to 34w
What are contraindications to tocolysis?
IUFD lethal anomaly NR-FHT severe PreE/eclampsia PPROM Hemodynamic instability Chorio Abruption
How does magnesium act as a tocolytic?
Blocks calcium to inhibit uterine contractility
When should nifedipine be used for tocolysis?
NOT with Mag, so after 32w. (again blocks Ca, blocks contractility)
When should indocin be used for tocolysis?
Prior to 32 weeks
What are the doses of steroids for lung maturity?
Metamethasone 12 mg q24h x2
Dexamethasone 6mg q12h x4
When is a standard dose of steroids indicated?
24-34w when delivery is anticipated within 7 days
What are the benefits of steroids?
decreased respiratory distress
decreased intracranial hemorrhage
decreased NEC
decreased death
When are late preterm steroids indicated?
34-36w when the patient has not previously received steroids. shown to decreased respiratory distress
When is a theoretical risk of late preterm steroids?
neonatal hypoglycemia
When are “rescue” steroids indicated?
24-34w if first course was 14+ days prior (can consider at 7 days)
Are rescue steroids indicated in PPROM?
There is insufficient evidence to support this
When is magnesium for fetal neuroprotection indicated?
<32w
What is the benefit of magnesium for FNP?
Decreased CP and death
When should vaginal progesterone be offered to a patient?
If they have a h/o PTD, start at 16-24w
What is a hx indicated cerclage and when should it be placed?
h/o 2T loss or h/o cerclage. Place at 13-14w
What is a US indicated cerclage and when should it be placed?
h/o PTB <34w AND CXL <25mm. Place at <24w
Should cerclages be used in twins?
No! increases chance of PTD x2
In a patient with a h/o PTD, when and how often should CLX be measured?
q2w from 16-23w
What are the doses of progesterone to prevent PTL?
Vaginal 200mg nightly
IM 250mg weekly 16w-36w
How does cerclage decrease you chance of PTD?
Decreases delivery before 35w by 30%
How does PIH affect lifetime disk of cardivascular disease?
Increase x5
What percentage of pregnancies have PreE?
2-8%
What are RF for PIH?
Nulliparity Twins H/o cHTN T2DM/gDM Thrombphilia Lupus BMI>30 APAS AMA CKD ART OSA
What percentage of gHTN go on to develop PreE?
50% (esp if dx before 32w)
How is proteinuria defined?
P:C 0.3
24h urine protein 300g
If no other labs, urine dip with 2+ protein
What is the pattern of LFT’s in PreE?
AST>ALT
What does PreE put you at risk of?
MI Pulmonary edema Stroke ARDs Renal failure
What value of LDH is concerning for HELLP?
LDH >600
How much are PLT expected to drop a day in HELLP? When is the nadir?
PLT drop 40% a day, nadir at 23h PP, if still dropping on PPD#4- not likely due to HELLP
What percentage of HELLP occur in PP period?
30%
What percentage of HELLP won’t have underlying HTN or proteinuria?
15%
How does HELLP normally present?
90% present with RUQ/malaise
50% present with only n/v
What does PRES stand for and how does it present?
Posterior Reversible Encephalopathy syndrome, presents as vision loss/deficit, HA, AMS
How is PRES shown on MRI?
vasogenic edema, hyperintensities on posterior brain
What are some markers of early onset PreE?
sFlt-1 and PIGF (although neither is sensitive or specific)
What can we do to prevent PIH in pregnancy?
Start 81mg ASA (optimally by 16w) can start anytime between 12-28w
What is the mechanism of ASA?
inhibits thromboxane A2
How does death occur in eclampsia?
hypoxia, trauma, aspiration PNA
When is a seizure not likely d/t eclampsia?
h/o seixure d/o, if starts 48-72h PP, if happens when already on mag
What long term deficits do patients with eclampsia have?
None! However will show up as white matter loss on MRI
How is eclampsia normally preceded?
Occipital/frontal HA
Blurred vision
Photophobia
AMS
What percentage of eclamptics won’t have classic PreE?
20-38%
What is the chance of seizing if not on mag?
w/o SF: 1.9%
w/ SF: 3.2%
What is the therapeutic range of Mag?
4.8-9.6 mg/dL
What is the number needed to treat with magnesium for symptomatic severe pre-eclamptics?
36!
What are the mag toxicities and at what level do they occur?
loss of DTR’s >9
respiratory paralysis >12
cardiac arrest >30
What are contraindications to mag?
Myasthenia gravis
Hypocalcemia
Renal failure
MI
What is the onset of hydralazine and why?
10-20 minutes, must be metabolized after attachment to vessel wall
What is the onset of IV labetalol?
1-2 minutes
What is the onset of PO nifed?
5-10 minutes
Max dose of PO labetalol in one day?
2400mg
Max dose of IV labetalol in one day?
300mg
Max dose of IV hydral in one day?
20mg
Max dose of PO nifed in one day?
180 mg
What is the normal physiology in PP period in terms of BP?
extravascular fluid goes intravascularly, increase in BP normal
What is the proposed mechanism of how NSAIDs can raise BP?
NSAIDs block PG which normally cause vasodilation, so potentially could block vasodilation
Why don’t we use methyldopa in PP period?
potentially can exacerbate PP depression
What BP do we start anti-HTNives in PP period?
150/100
cHTN affects what percentage of pregnancies?
1%
When does the SVR nadir in pregnancy?
16-18 weeks, diastolic drops more than systolic
What percentage of cHTN will develop PreE?
20-50%
What are signs a cHTN developed PreE?
sudden increase in BP or increase in proteinuria, decreasing PLT is unique to PreE; sometime Uric Acid can be helpful!
What is the relative risk of perinatal mortality when comparing cHTN w/o PreE to cHTN w/ si PreE?
3.6
How do ACE/ARBs affect pregnancy?
fetopathic, cause malformations in first tri, esp in women who have used these >4 years
Why is it important not to tank the BP in pregnant women?
Because the placenta does not auto-regulate blood flow
What are some maternal risks of cHTN?
Stroke Pulmonary edema Renal failue gDM (maybe confounded) C/s (1.8 fold) PPH (2x)
What are some fetal risks of cHTN?
low birth weight PTD (medically indicated) IUGR (2x) Mortality (increased by 2-4x) Abruption Congenital anomalies
What congenital anomalies are associated with cHTN?
Heart defects
Hypospadius
Esophageal atresia
When is delivery indicated for cHTN?
without medications: 38-39w
with medications: 37-39w
What is thrombocytopenia of pregnancy?
PLT <150
What percentage of women are affected by thrombocytopenia of pregnancy?
7-12%
How does thrombocytopenia of pregnancy present?
Petechiae Ecchymosis Epistaxis Gingival bleeding AUB (heavy or intermenstrual)
What percentage of thrombocytopenia of pregnancy are due to gestational thrombocytopenia?
80%
What percentage of women will have gestational thrombocytopenia?
5-10%
When does gestational thrombocytopenia normally present?
2nd or 3rd trimester
What level of PLT is usually associated with gestational thrombocytopenia?
PLT>75
What symptoms do women with gestational thrombocytopenia have?
None, they are normally asymptomatic
How long does it take for PLT to return to normal in a woman with gestational thrombocytopenia?
Usually 2-3 months PP
What percentage of thrombocytopenia of pregnancy is due to PIH?
5-20%
If a pregnant woman’s PLT<100, what is the most likely dx?
ITP, likely not gestational if <100
What is fetal-neonatal alloimmunie thrombocytopenia?
Like the PLT equivalent of Rh dz, however can occur in G1. Maternal immune system attacks di-allele antigen on PLT causing destruction of fetal PLT
What level of fetal PLT necessitates CS?
Fetal PLT<50
What percentage of fetuses of mothers with ITP will have thrombocytopenia and why?
25% due to IgG crossing placenta
When is a PLT transfusion indicated?
pre-operatively if PLT<50 or if in DIC (although consumptive and will drop PLT quickly)
What level of PLT in ITP warrants treatment?
ITP when PLT <30
What is the treatment for ITP when PLT are low?
Prednisone (0.5-2 mg/kg/day) although normally 10-20mg daily x 21 days, then taper
Can use IVIG (1g/kg) in refractory cases
What is contraindicated during L&D in patients with ITP?
operative delivery or FSE d/t increased risk of fetal thrombocytopenia and subsequent hemorrhage
How much more likely is a pregnant women to get a DVT vs a non-pregnant woman?
4-5 times more likely
Which layer of the uterus is important in causing alterations in the clotting pathway?
the decidual layer
What is the incidence of DVT’s in pregnant women?
0.5-2/1,000
What percentage of pregnancy related deaths are due to DVT’s?
10%
What percentage of DVT’s in pregnancy are due to factor V Leiden heterosygosity?
40%
What percentage of DVT’s in pregnancy are due to prothrombin G202010A?
17%
How much does anti-thrombin deficiency increase the risk of DVT in pregnant women?
25x the risk!
Which thrombophilias need anticoagulation in the antepartum and postpartum periods?
Factor V Leiden
prothrombin 20210A
Anti-thrombin deficiency
Who needs a thrombophilia workup?
person h/o DVT or high risk first degree relative
Which tests should be done in a thrombophilia workup?
Factr V Leiden Prothrombin20210A AT3 deficiency Protein C and S deficiency APAS
Which thrombophilia should not be tested for during pregnancy and when should it be tested?
Protein S (some will be bound during pregnancy making levels falsely low) Test at least 6w after a clot, not while pregnant, on AC or on hormonal therapy
At what risk level should someone be started on AS antenatally?
3% risk of DVT
When should antenatal anticoagulation be started?
first trimester through 6w PP
How to handle AC around delivery?
Hold 12 hours before induction (for neuraxial anesthesia)- can check aPTT to make sure it’s ok
Restart 4-6h after Vag delivery, 6-12h after CS
When is an Rh negative woman exposed to the rh antigen?
miscarriage ectopic antenatal bleeding delivery amniocentesis D&C for missed ECV
Where does rhogam come from?
Anti-D Ig from donated plasma
How much is in the standard dose of rhogam and how much fetal blood will that cover?
300mcg, covers 30ml whole fetal blood or 15ml fetal RBC
When should women recieve rhogam?
When exposed to Antigen (bleeding), at delivery and at 28w
How long is rhogam hypothetically covering the mother for?
12w
At what GA is RhD present in a fetus?
7w3d
When would you give a microdose of rhogam (50 mcg)
SAB <12w, if >12w give 30mcg
What is “weak D”?
A variant of Rh D some people have on their RBC’s
How should “weak D” be treated?
treat like Rh negative in pregnancy
If donating blood treat like Rh positive
What percentage of neonates born to Rh neg mothers will be Rh negative as well?
40%
how much fetal blood can the “rosette” test detect?
> 2 ml fetal blood
What is the rosette test?
Put Rh-D Ig into Rh neg maternal blood. Will bind to Rh on fetal cells Will clump (form rosette)
What test comes after the rosette test and how does this work?
K-B after rosette, looks for percentage of fetal blood in mom’s blood by Hgb F
What diseases may have false positive KB and why?
Sickle cell and some thalessemias
increased HgB F in normal maternal blood
What percentage of pregnancies will have VB in the 3rd tri?
4-5%
What is bloody show?
blood from sheering of small vessels in cervix, can precede labor by 72h
What are some RF of placenta previa?
Increased parity AMA ART h/o termination h/o Uterine surgery smoking cocaine non-white male fetus
What is recommended for placenta previa?
pelvic rest, no orgasms
Delivery at 36-37w by CS
What is a low lying placenta?
placenta within 2cm of os
Chance of accreta in patient with previa and h/o 1,2,3,4 c/s
1 CS = 11%
2 CS = 40%
3 CS= 61%
4 CS = 67%
Risk factors for placental abruption
h/o trauma smoking cocaine HTN PPROM
How does placental abruption present?
80% have VB
70% have ab pn
what is the cause of abdominal pain in abruption and what is this finding called?
bleeding into myometrium: Couvelaire uterus
How much of the placenta needs to abrupt to cause a demise?
50%
What is a blood marker that can predict abruption?
AFP > 280
Types of vasa previa?
Type 1: villamentous cord insertion, vessels near os
Type 2: bi-lobed or succenturiate placenta, vessels over os
Type 3: atrophy of placenta near os, vessels at edge exposed
How much blodd is running through spiral arteries per minute at term?
600cc blood per minute
What is required for hemostasis as the placenta detaches?
Needs to coagulate and need to contract to help tamponade
What is the chance of acquiring an infxn from a blood transfusion?
HepB: 1/200,000
HepC: 1/1.3 million
HepB: 1/2 million
How much volume is in 1u pRBC?
300cc
How much should 1u pRBC increased you hgb/hct?
hgb by 1 pt, hct by 3%
what ratio of RBC:FFP:PLT should we use in obstetric hemorrhage?
1:1:1 (6 pack)
When should you give cryo and why is it a good product?
Give cryo if fibrinogen <200
Good because it is concentrated (volume only 30cc)
What is the blood volume of FFP?
250cc
What is the blood volume of one 6-pack of PLT and how much should it increase your PLT?
300cc, should increase PLT 42
What is the definition of massive transfusion protocol?
> 6u pRBC over 2 hours or >10u pRBC over 24h
What are the classes of hemorrhage?
Class 1: 1L (15% of volume) feel dizzy
Class 2: 1.5L (25% of volume) tachycardic, orthostatic
Class 3: 2L (35% of volume) tachycardic, hypotensive
Class 4: >2.5L (>40% of volume) oliguric
When should you consider repleting Calcium during a transfusion and why is this important?
after 4u pRBC, need Ca for uterus to contract and stop bleeding
how much do you expect cryo and FFP to increase your fibrinogen
5-10 points
How is sickle cell inherited?
Autosomal recessive
If a patient has sickle cell in pregnancy what is she at risk of?
PTL PPROM PP infection IUGR Low birth weight SAB Stillbirth
What supplements do pregnant women with sickle cell need?
4 mg folic acid (due to increased RBC turnover)
What is the normal treatment for sickle cell and why isn’t it used in pregnancy?
Hydroxyurea, it’s teratogenic
What percentage of African Americans have Sickle cell trait?
50%
How is sickle cell diagnosed?
HgB electrophoresis
At what gestational ages can you do CVS and amnio?
CVS 10-12 weeks, amnio >15 weeks
What qualifies as anemia in pregnancy?
1T: 11/33
2T: 10.5/32
3T: 11/33
How much does blood volume and RBC mass increase in pregnancy?
Total blood volume expands 50%, RBC mass increased 25%
What is the recommended daily allowance of Fe in normal pregnant lady?
27mg
What is the most sensitive test for anemia of pregnancy and what is its normal value?
Serum ferritin, normal >10 mcg/dL
What happens to a fetus if mom’s Hgb is below 6?
Abnormal fetal O2 > NR-FHT
Decreased amniotic fluid
Fital cerebral vasodilation
Fetal death
Which is more effective? PO or IV iron
At days 5 and 14 IV was shown to have higher response in HgB, however at 40 days the responses were the same
What is the daily recommended allowance of folic acid in a normal pregnant woman?
400 mcg/day
Ddx for microcytic anemia
Iron deficiency
Thalessemia
Copper deficiency
Lead poinsoning
Ddx for normocytic anemia
Acute blood loss Early iron def Anemia of chronic dz BM suppression CKD Autoimmune hemolytic anemia
Ddx for macrocytic anemia
Folic acid deficiency
B12 deficiency
Liver dz or EtOH
What is the pathophys of hemolytic dz of fetus/newborn?
IgG cross placenta to attack fetal RBC > intravscular hemolysis> dcreased oncotic pressure> extravisation of fluid and hydrops
What are the 4 signs of fetal hydrops?
ascites
pericardial effusion
pleural effusion
skin edema
How are Ab screened at first prenatal visit?
indirect coombs test
Known Rh+ RBC mixed with tested maternal plasma
Maternal Anti-D AB will adhere to these D+ RBCs
RBC’s are washed in Coomb’s serum (antihuman globulin) > RBC’s tht are coated will show up positive
