MFM Flashcards
Gestational HTN is defined as
> 140/90 after 20 weeks of pregnancy
Gestational HTN investigations
Look for preeclampsia
1) proteinuria 2) severe features of preeclampsia 3) assess fetal status
Severe Gestational HTN
≥160/110
Postpartrum Hypertensive mgmt
Oral or IV medications, similar to those used in non-pregnant patients
Pathogenesis of preeclampsia
Preeclampsia occurs because of placental circulation abnormalities, where the large spinal arteries fail to penetrate the myometrial portion, instead the vessels of the myometrium are narrowing, resulting in hypoperfusion and ischemia.
An exaggerated state of oxidative stress develops in the placenta which in turns adversely affects angiogenesis. As the pregnancy develops, anti-angiogenesis factors are released into maternal blood resulting in wide spread vascular inflammation, endothelial dysfunction leading to HTN and preeclampsia
Severe preeclampsia defined as
- 160/110 with
- proteinura >3g/dL
- end organ dysfunction
- fetal effects - Onset <34 weeks
Dx of Preeclampsia and definition of pre-eclampsia
Definition:
Preeclampsia refers to the new onset of HTN with proteinuria OR the new onset HTN with significant end-organ dysfunction with or without proteinuria after 20 weeks gestation
- two readings of ≥140/90 plus
- proteinuria
- end organ dysfunction (elevated AST/ALT, BUN,CR, Pulmonary edema)
- fetal effects
women with preeclampsia are at risk for life-threatening events such as
CVA Retinal injury Placental abruption AKI ICH Hepatic failure pulmonary edema eclampsia thrombocytopenia MI ARDS
the fetus in preeclampsia is at increased risk of
IGUR, oligohydraminos
Approach to preeclampsia
- Acute BP target: <160/110 (reduction by ~25% in minutes to hours)
Labetalol 20mg over 20 minutes, then 40, 80mg to max 300 or infusion 2-3mg/min
Nifedipine 5-10mg q 30-45, max 80mg/d
Hydralazine 5-10mg to max 20mg - Magnesium 4g over 20 minutes then 1g/hr infusion for 24 hours
- Betamethasone 12mg q 24hr (x2) (in addition to lung maturity, it improves UA diastolic flow of the placenta - if suspect to deliver within the next 7 days)
- Fluid restrict for 80ml/hr
Approach to Eclampsia
- Magnesium 4g/20minutes then 1g/hr.
2. for status, use Benzos
HELLP syndrome dx
- Hemolysis - peripheral smear abnormalities, serum bili elevated, low hepatoglobin, or severe anemia
- elavated AST/ALT x 2
- platelets <100
Approach to HELLP
- Severe gestational HTN mgmt
- Delivery
○ Stabilize mother and assess fetal status
○ Transfer to a tertiary centre due to risk of rapid complication development
○ Severe gestation HTN should be treated with Labetalol
○ Women with complications list above should promptly deliver
○ Manage hepatic hematoma with volume replacement and transfusion as necessary
○ RBC threshold - varies, UTD 70g/L
○ PLT threshold - <50 = if c-section impending, <20 Otherwise
Phone Assessment:
- Cervix (dilation/effacement/length)
- contractions (frequency, durations and strength)
- membrane (intact/rupture, if ruptured how long and abx)
- baby (FHR -good variability)
- medications given - betamethasone, abx, tocolytics
- maternal (GDM, PIH, GBS, GTPAL)
Placental Abruption refers to
partial or complete separation of the placenta prior to delivery of the fetus. Which can be concealed or revealed
Is placental abruption blood maternal or fetal?
Maternal Hemorrhage, from the decidua basalis
Maternal vasculature may be arterial or venous
Approach to placental abruption
- maternal hemodynamic assessment (manage coags)
- If fetal HR is non-reassuring, expeditious delivery is indicated
- If fetus <34 weeks and mother is stable - conservative mgmt until 37 weeks is recommended with tocolytics and antenatal steroids
- If fetus 34-36 weeks GA and mother are stable, expectant delivery is appropriate
- All pregnancies with acute abruption ≥36 weeks GA should be delivered
Placental Previa definition
Placenta previa refers to the presence of placental tissue that extends over the internal cervical os.
Sequelae include the need for c-section as well as the potential for severe antepartum bleeding, preterm birth and postpartum hemorrhage.
placental previa mgmt
- achieve and/or maintain maternal hemodynamic stability
2. determine if emergency c-section is indicated.
placenta accrete
is the growth of the placenta into uterine scarring. Its a surgical emergency with immediate removal and possible hysterectomy.
Preterm Labour pathogenesis
- premature activation of the maternal or fetal HPA axis related to stress
- exaggerated inflammatory response/infection
- abruption
- pathologic uterine distention
The goal of delaying PTL is to
allow for antenatal corticosteroid administration, and allow for safe transfer.
PTL mgmt:
- Betamethasone if between 24-34 weeks (lung/gut/neuro protection)
- tocolytic for 48 hours (nifedipine, Indocin)
- Abx (GBS)
- Magnesium (neuro protection)
Tocolytic use in PTL:
- Nifedipine = loading dose of
10mg PO q 30 until contractions stop (max 40mg/2hours) then 1 hour after loading dose q12 hours for 48 hours - Indocin (only if <28 weeks) 100mg PR then 25mg PO q 6 hours x 48
PPROM refers to
Rupture of membranes prior to the onset of labour in pregnancy <37
complications of PROM
- PTL/PTB
- fetal/neonatal infection
- maternal infection
- umbilical cord compression/prolapse
- failed induction resulting in c-section
- pulmonary hypoplasia
Chorioamniotis dx is suspected when
- maternal fever >38 degrees
- fetal HR >160
- signs of maternal sepsis
Dx is confirmed with placental histopathology
Zygocity refers to
the description of number of eggs fertilized
Chorionocity is
the number of placentas
amniocity is the description of
number of amniotic sacs
Diachorionic twins
DI-achorionic twins (two placenta) could be dizygotic (fraternal) or monozygotic (identical) twins
safest forms of twins
monochorionic twins
One placenta
- always monozygotic (identical)
- amnioicity depends on timing of division of fertilized ovum
- monochoro twins are the most complicated version of twins
Monochorionic twins complications
- twin to twin transfusion syndrome
- twin anemia polychythemia sequence
- selevtive intrauterine growth restrictions
- twin reversed arterial perfusion
- dual damage of monochorionic twins
Cord gas UV and UA equals who’s blood
UV = placental UA= Babies
Maternal assessment questions:
- Age
- GA
- Maternal Hx: (GTPALS)
- Contractions (x in 10 with mod/mild/severe strength)
- passage (dilation/effacemnt/consistency)
- Last VE (dilation/length/position)
- TESTS (urine, ferrying, GBS)
- fetal assessments
- fetal problems
- antenatal problems
- antenatal treatment
Factors that promote or imitate labour
- fetus
- myometrial activation
- membrane rupture
- hormones
(prostaglandin, progesterone, estrogen, oxytocin)
Tocolytics are
medications used to suppress premature labour
Examples of tocolytics are
indomethacin and nifedipine (adalat)
Tocolytics are administered to allow
for prelabour growth. they also allow for administration of betamethasone to allow fetal production of surfactant
Which tocolytic is preferred
Nifedipine is typically used first because it has less adverse effects on PDA and NEC
MOA of Adalat
is a CCB that blocks calcium influx to inhibit labour contraction
Indomethacin drug classification/moa
NSAID and tocolytic. It functions by inhibiting prostaglandin synthestase.
-reduction of inflammation inhibits production of labour
At what weeks is Indomethacin appropriate to give
Between 28-32 weeks (text book) but really, <28 weeks. or just dont fucking use it. plus who wants to give anything PR
Induction methods
- Membrane sweep
- Prostaglandin tampons
- Amniotomy
- Foley catheter in cervix
- Oxytocin
What does a membrane sweep mean
breaks the barrier of the cervix which beings the cascade of inflammation and uterine preparation for birthing
What is a prostaglandin tampon
They are used to apply prostaglandin to the cervix to initiate the birthing cascade. Prostaglandin is contraindication in women with uterine scarring from C-Section
Whats an amniotomy
Is a manual ROM by amniohook
Whats the role of ‘Foley catheter in cervix’
To stimulate the release of inflammatory factors and also application of pressure on the internal os of the cervix which assists in thinning the cervix
Why is oxytocin used for induction
Oxytocin effectively works by increasing intracellular calcium.
Oxytocin is useless when the cervix is fully constricted
When and why is induction undertake before ___weeks
typically undertake before 41 + 3 because the risk of still birth steadily climbs beyond that point
The 5 P’s of labour
- passage
- passenger
- power
- position
- pscyhe/parter
When is transport not recommended in the setting of labour
When >4 cm (advised to birth in location)
Active labour is defined as
Progressive cervical dilation with contractions >30seconds with 2 constrictions in 10 minutes
Four stages of labour
- onset of involuntary, painful contractions (cervic <3cm)
- Full cervical dilation to delivery of fetus
- delivery of baby to delivery of placenta
- post-birth
Social abortion is allowed up to
24 weeks in BC
Genetic-abnormalities D&E can occur up to
~28 weeks GA
Abortions in the community setting aren’t typically offered beyond
14 weeks
The four major hypertensive disorders related to pregnancy include
- gestational HTN
- Chronic HTN
- Preeclampsia
- preeclampsia super imposed upon chronic hypertension
When do you give midazolam in preeclampsia
When they’re eclamptic and in status seizures, first line magnesium
Seizure prophylaxis in preeclampsia
4g of mag over 20minutes, followed by 1g/h for 24 hours
In addition to fetal lung maturity, and decreasing risk of IVH what do glucocorticoids improve in preeclampsia
Improve UA end-diastolic flow in the short term
Maintenance fluids of preeclampsia
80ml/hr
Whats the number 1 killer in preeclampsia
Pulmonary edema
Treatment for magnesium toxicity
calcium glutinate 15-30ml of 10% over 2-5 minutes
Is preeclampsia an indication for c-section
No. Not unless harm to mother or fetus
Why is Labetalol the only beta-blocker used in preeclampsia
Other beta blockers are teratogenic
In the setting of prevention, whats the only drug shown to reduce risk of preeclampsia
low dose asa
Eclampsia is a clinical diagnosis based on what
the occurrence of new-onset tonic-clonic, focal or multifocal seizures in a women with a hypertensive disorder of pregnancy
Whats the pathogenesis of eclampsia?
- breakdown of the auto regulatory system of the cerebral circulation leading to hyperperfusion, endothelial dysfunction and vasogenic/cytotoxic edema
Diagnosis of HELLP is based on the presence of
Hemolysis (severe anemia, peripheral smear abnormalities)
Elevated liver enzymes (AST/ALT X 2 upper limit)
Low platelets (<100)
Complications of HELLP
placental abruption AKI hepatic rupture pulmonary edema retinal detachment preterm with LBW DIC
Pathophysiology of placental abruption
The immediate cause of placental separation is RUPTURE of maternal vessels in the decimal basalis. The ruptured maternal vessels may be an artery or a vein.
Thrombin (Factor 2) plays a key role in the clinical consequence of placental abruption.
Clinical features of placental abruption
- vaginal bleeding
- abdominal pain
- contractions with irregular pattern
- uterine rigidity and severe tenderness
- non-reassuring FHR
Dx of Abruption
clinical and based on the abrupt onset.
- kleighauer test is a blood that tests for present of fetal hemoglobin in maternal blood
- abruption is usually visible on US
In PTL when can we give steroids between?
24 and 34 weeks
Risk factors for PTL
- Prior PTL (Strongest risk factor)
- extreme maternal age
- multiple GA
- fetal disorder
- poly/oligohydraminos
- maternal medical conditions
- short cervix length
- positive fFN between 22-34 weeks
Tocolytics no longer used
Ventolin, magnesium, nitro patch, terbutaline
Dx of PROM
is clinical, based on visualization of amniotic fluid coming from cervical canal.
- ferning is the other gold standard
- amnisure is a POC used to determine PPROM
- Nitrazine testing (pH testing of fluid)
Extreme Preterm age
<27 weeks
very prerm age rage
27-31 weeks GA
Moderate to late preterm
32-36+6
Whats the survival rate of Premies born at 24 weeks
59%
Interventions of reduced PTB
vaginal progesterone cerclage of cervix low dose asa removal of large fibroids prevention of multifetal gestations
Whats the number 1 complication of multiple gestation
preterm birth
What does Di-Di pregnancy mean?
Dichorionic-Diamniotic
two separate placentas
two separate amniotic sacs
What does Mono-Di mean?
Monochorionic-Diamniotic
1 shared placenta, 2 amniotic sacs
What does mono-mono twins mean
Monochorionic-Monoamniotic
1 shared placenta, 1 share amniotic sac
What is Twin-to-Twin transfusion syndrome
fetal to fetal transfusion of a large volume of blood causes fluid discordance.
Baby A becomes anemic and has oligohydramnios, where baby B becomes polycythemic and develops CHD and polyhyradminos
whats Twin anemia polycythemia sequence (TAPS)
Baby A born with 2x hemoglobin than baby B.
Small volumes of RBCs feto-fetal transfusion causes discordant hemoglobin
More insidious because some volumes are being transfused over a slower period of tie.
What is true labour
Progressive cervical dilation, effacement or both resulting from regular uterine contractions (2 or more in 10 minutes lasting 30-60s)
What does prostaglandins have to do with labour
Inflammatory response creating arachidonic acid prostaglandin syntheses
What does progesterone inhibit?
Prostaglandin production
Indocin (indomethacin) inhibits the production of?
Arachnoidic acid, which inhibits prostaglandin synthesis
Labour is a continuous process of contractions altering with relaxation by increasing and decreasing…
intracellular calcium
Four T’s of post-partum bleeding
tissue (placenta retention)
trauma (tearing vessels)
tone (inability of the uterus to self-contract)
thrombin (bleeding disorders)
Initial assessment for < 34 weeks gestation with symptoms of PTL
- check GA AGE
- Palpate contractions
- sterile sepeculum exams; (cultures, R/O ROM, take FFN swab)
- perform digital assessment of cervix
Whats cervical incompetence/insufficiency
the inability of the uterine cervix to retain pregnancy in the absence of the signs and symptoms of clinical contractions or labour or both in 2nd trimester
Whats the timeline for first, second and 3rd trimester?
- 1-12
- 13-26
- 27 +
Corticosteroid prophylaxis benefits are seen as early as
4 hours
Maximum effect of corticosteroids in PTL
48 hours - 7 days after first dose
Maternal cardiovascular differences
- increased CO
- dilution anemia, but increased RBC production
- increased blood volume
- increase preload, decrease afterload from declining SVR
- declining SVR from prostaglandin
- increased hR by 20
- left axis deviation
- increase in Pao2
maternal Resp differences
- respiratory alkalosis (pH >7.4 decrease CO2 30-32mmHg)
- decreased FRC 2nd to babe/diaphragm
- decreased chest compliance
- decrease v/Q
- progesterone stimulation produces an increased resp drive
maternal GI/GU differences
higher risk of gastric aspiration 2nd to lower esophageal sphincter tone
increased grr with increased renal BF , decreased CR to 35-45
What are dizygotic twins
non-identical twins. 2 eggs, 2 sperms
what are monozygotic twins
identical. 1 egg 1 sperm
Three differentials for HELLP
- Acute fatty liver of pregnancy
- Thrombotic thrombocytopenia purpura
- Pregnancy induced hemolytic ureic syndrome
Pathophysiology of HELLP syndrome
It probably represents a severe form of preeclampsia but to relationship between the two disorders remain controversial.
Microangiopathy and activation of intravascular coagulopathy can account for all the laboratory findings of HELLP syndrome
Benefits of delayed cord clamping
- decreases the need for transfusion, increase blood
- volume 20-40ml/kg increase
- increase stem cells
- decrease risk of NEC and IVH
