Midterm Flashcards
Blood volume changes
-increase by 50%
4L to 5.5 L
RBC changes
- RBC volume increases only about 25% which results in a dilutional anemia
- blood flows faster due to lower viscosity
cardiac output changes
increases 40% mostly due to increases in stroke volume and not so much heart rate
vasculature changes
- decreased systemic vascular resistance resulting in systolic decrease 5 points and diastolic decrease 10 points
- gravid uterus can compress vena cava resulting in supine and orthostatic hypotension, varicose veins, edema, and hemorrhoids
heart sound findings
normal to find systolic ejection murmur and S3
regional blood flow changes
-increased flow to kidneys and uterus
respiratory changes
- increase in oxygen consumption and minute ventilation (tidal volume x RR)
- tidal volume increased more than respiratory rate
metabolic acidosis
- increase in minute ventilation exceeds oxygen consumption leading to respiratory alkalosis and hyperoxemia
- leads to metabolic acidosis
- decreased bicarb on labs is normal
dyspnea of pregnancy
- lower CO2 trigger to breathe
- can feel short of breath often which is normal
gastrointestinal changes
changes mediated by progesterone
- increased appetite, food cravings
- increased cholesterol concentration
- increases colon transport time
- decreased gallbladder emptying time
- nausea, decreased swallowing
- decreased gastric and lower esophageal sphincter tone
- bleeding gums
renal changes
- increased urine outflow
- can overwhelm absorption ability
- can find protein in urine
- ureters are dilated due to decreased peristalsis from progesterone and effect of fetal head on ureter
metabolic changes
- increased insulin resistance, serum triglycerides, lipolysis
- increased cortisol
endocrine changes
- pregnant women create ketones in 4-6 hrs versus a normal 2 days and need to eat 300-500 more cal/day (esp. fat/protein)
- increase in aldosterone where lack of can lead to preeclampsia
hematological changes
- platelet numbers stay stable
- clotting factors increase
- iron stores decrease due to increase RBC production
- WBC not reliable indicator of infection if pregnant
weight changes
- frequently weight loss in 1st semester due to N/V
- by 20 wks nearly all have reached or passed baseline weight
- expected gain 1#/wk after 20 weeks
- if not expected weight loss after delivery then retaining fluid somewhere
oxygen transport to fetus
- want large surface area and decreased thickness to increase O2 diffusion across placenta
- hemochorial placenta is most efficient at O2 delivery but has increased blood loss when placenta delivers
placenta versus lungs
- placenta receives 60% CO and lungs receive 100%
- placenta metabolically active and uses 30% O2 delivered, lungs use <5%
- V/Q mismatch in placenta is normal and pathologic in lungs
fetal compensation for O2
- CO enhanced at a rate 10X greater than an adult
- hemoglobin is higher
- blood with higher O2 saturation is shunted to essential vascular beds
fetal hemoglobin
contains a gamma chain that does not allow it to respond to DPG and decrease O2 affinity, therefore fetal hemoglobin has higher O2 affinity
fetal circulation
- placenta acts as small intestine, kidneys, lung
- blood in IVC has 2 different streams with minimal mixing
fetal circulation after birth
- increase in systemic pressure causes foramen ovale to close
- ductus arteriosus becomes the ligamentum arteriosum
- ductus venosus becomes ligamentum venosum
- left umbilical vein becomes ligamentum teres
- umbilical arteries become lateral umbilical ligaments
immunological changes in pregnancy
- can become septic easier
- viral, bacterial, and fungal infections are more severe
goals of prenatal care
- reduce maternal and fetal morbidity/mortality
- reproductive life planning
- promote lifelong health behaviors
individual care model
- 1 patient per 1 MD
- majority of practices
group care model
- multiple patients with similar due dates grouped together
- social aspect due to being able to relate to each other
- experienced with pregnancy can help new to pregnancy
Complete history
- medical and surgical
- OB and gyn
- meds/allergies (may need to modify Rx)
- family/genetic (inheritable disease)
- substance abuse (all get urine drug screen)
- psychosocial
physical exam (initial Ob visit)
- be aware of the normal abnormal
- identify problem list for months long management
ascertainment of gestational age
- determines gestational milestones
- by history using LMP, 1st positive pregnancy test
initial sonogram
- earliest sonogram with a viable fetus is most accurate
- 1st trimester ultrasound accurate within 1 week +/-
- 2nd trimester ultrasound accurate within 2 weeks +/-
- 3rd trimester ultrasound accurate within 3 weeks +/-
- determine viability, gestational age, and location of pregnancy
goals of initial OB visit
- generate problem list to manage throughout pregnancy
- encourage healthy behaviors
- discuss reproductive life planning
prenatal CBC
- screen for anemia (typically Fe deficient)
- thrombocytopenia (establish baseline)
prenatal blood type and antibody screen
-screen for isoimmunization (Rh)
prenatal rubella screen
- susceptibility, postpartum immunization
- rubella is teratogenic
prenatal RPR
- screen and treat congenital syphilis
- tested three times
- syphilis teratogenic
prenatal Hep B screen
post exposure prophylaxis at delivery for baby
prenatal HIV screen
- screen and treat to decrease risk of vertical transmission
- baby has 25% chance of contracting without treatment
prenatal gonorrhea/chlamydia
neonatal ophthalmia
screen for malformation
- nutritional (folate needed for DNA synthesis)
- genetic
- vascular
- medical
deformation - mechanical fetal anomalies
- fibroids
- amniotic band syndrome
- potter sequence (no fluid around body)
teratogenesis fetal anomalies
- chemical
- radiation
- infectious disease
serum screen for aneuploidy
- quad screen
- cell free DNA screen (chromosome count/sequence) (typically for high risk due to cost)
- ultrasound 18 weeks (screening test)
- fetal echo 22 weeks (screening test)
- amniocentesis (diagnostic test)
prenatal visit schedule
4-28 weeks: every 4 weeks
28-36 weeks: every 2 weeks
36-40 weeks: every week
40+ weeks: 1-3 times/weeks
8 week visit
- assess and manage common 1st trimester symptoms (fatigue, nausea)
- bleeding? (not normal 1st trimester)
- assess viability
12 week visit
- follow up prenatal labs
- typically peak of nausea, fatigue subsiding
- assess viability and reassure loss is rare after 1st trimester (1-2%)
16 week visit
- can typically determine gender
- most 1st trimester symptoms resolved
- check fundal height (should be halfway between pubic symphysis and umbilicus)
- check fetal heart tones and movement
- aneuploidy screen
- fetal anatomy screen
20 week visit
- follow up on aneuploidy screen and any consultations
- most women feel fetal movement by now
- assess weight gain
- discuss feeding and encourage breast feeding
24 week visit
- fetal movement reliable felt
- weight gain should be 1 lb/week
- watch BP and protein (preeclampsia can occur 24+ weeks)
- evaluate/counsel preterm labor symptoms (cramping, pressure, bleeding, leaking)
- fundal height in cm nearly same as weeks +/- 2
28 week visit
- discuss 3rd trimester symptoms (heart burn, back/feet pain, mild/moderate edema, lightheaded)
- glucose tolerance test
- rhogam if Rh negative
- constant pelvic pressure is normal, pressure that comes and goes could be contraction
30, 32, 34 week visits
- baby should be head down by week 34
- post partum birth control counseling
36 week visit
- vaginal/rectal swab for group B strep and urine PCR for gonorrhea/chlamydia
- discuss term labor symptoms (cramping, pressure, bleeding, leaking)
37-40 week visits
- check cervix upon request if symptomatic or if induction indicated
- spontaneous is typically better than induction
40+ week visit
- being seen twice per week
- test baby for well being
- most go in to labor 40-41 weeks and if not give induction date
APGAR
helps determine if resuscitation is needed after delivery
intrauterine apgar
- correlates well with degree of acidemia
- done at weeks 32 and later
- score 10 = pH >7.20
- score 0 = pH <7.2
- low amniotic fluid indicates chronic asphyxia and is always abnormal
nonstress test (fetal cardiotocography)
- tests for presence of neurocardiac reflexes which require non-acidotic CNS
- reactive = at least 2 accelerations (15 bpm x 15 sec) over a 20 minute period = normal
- nonreactive = hypoxemia
contraction stress test
-tests the fetuses ability to oxygenate during contractions
uterine artery velocimetry
- pregnant uterine artery is always maximally dilated
- useful for predicting fetal demise, particularly with fetal growth restriction
- absent and reversed end diastolic flow associated with fetal demise within a week
arrest of dilation
no cervical change in 2 hours
arrest of descent
- no delivery after 3 hours if nulliparous
- no delivery after 2 hours if parous
- add 1 hour if epidural present
stages of labor
-pre labor: (braxton-hicks) contractions thin cervix and prepare it for labor
-1st stage: cervix thins and dilates to 10 cm
0-4 cm early labor
5-8 cm active labor
8-10 cm transition
-2nd stage: pushing until baby born
-3rd stage: contractions to expel placenta
-4th stage: breastfeeding established and contractions so uterus will shrink
cardinal movements of labor
Every Darn Fetus Is Extremely Eager to Exit
Engagement Descent Flexion Internal rotation Extension External rotation Expulsion
pelvic inlet
- smallest diameter is antero-posterior
- widest diameter is transverse
- failure at this phase (engagement) typically occurs before complete dilation
mid pelvis
- smallest diameter is transverse
- widest diameter is antero-posterior
- descent, then flexion, then internal rotation must occur to get through
- failure at this stage is deep transverse arrest (no forceps used)
pelvic outlet
- all diameters generally wide enough
- fetus usually enters OA
- head then delivers through extension
- shoulders deliver through external rotation
- rest of body undergoes expulsion
- difficulty at this point may be assisted with vacuum/forceps
gynecoid pelvis
- 50%
- most common in Caucasian
- round, cylindric shape and wide pubic arch
- good prognosis for vaginal birth
anthropoid pelvis
- 25% white, 50% nonwhite
- long, narrow oval shape
- anteroposterior diameter is longer than transverse
- narrow pubic arch
- fetus may be born OP
- more favorable for vaginal birth, but not perfect
android pelvis
- 30%
- common in PCOS
- heart or triangular shaped
- narrow diameters and narrow pubic arch
- poor prognosis for vaginal birth
platypelloid pelvis
- 3%
- flattened, wide short oval
- transverse wide but AP diameter short
- wide pubic arch
- poor prognosis for vaginal birth
lie
- orientation of the fetal spine relative to maternal spine
- cephalic 95%
- breech 4%
- oblique & transverse 1% (not compatible with vaginal delivery)
presentation
- part of the fetoplacental unit closest to the cervix
- cephalic, breech, back, hand/arm, compound, placenta, cord
attitude
- degree of flexion of the fetal head (longitudinal lie)
- vertex and face will fit (well flexed/hyperextended)
- military and brow won’t fit
dilation
- how open the cervix is
- fully dilated 10 cm
effacement
-how “flat” the cervix is
station
- how low the fetus is in the pelvis
- superior to ischial spine = negative station
- inferior to ischial spine = positive station = 2nd stage labor
position
- the relationship between a designated part of the fetus and maternal pelvis
- OA is most favorable
baseline HR and pacemakers
- intrinsic rate 160 but predominance of vagal tone results in typical 140s rate
- AV junctional pacer rate 90
- idioventricular rate 60
bradycardia and causes
- rate <110
- hypoglycemia, hypothermia, hypotension, heart block/defect
tachycardia and causes
- rate >160
- more worrisome than bradycardia
- fever/infection, hyperthyroidism, arrhythmia, stimulants, acidemia
variations from baseline
- general rule all variations from baseline are reflexes designed to maintain homeostasis, particularly oxygen delivery
- can’t manage vascular beds, can only manage HR
variability
- increases in HR due to increase in O2 demand via sympathetic nervous system
- implies intact CNS
absent variability
- sleep (no more than 45 minutes)
- meds (opioids, mag)
- CNS injury (diagnosis of exclusion)
amplitude range classification
- absent: undetectable (possible CNS injury)
- minimal: undetectable to equal to or less than 5 BPM (possible CNS injury)
- moderate: 6-25 BPM (normal)
- marked: >25 BPM (unknown clinical significance)
accelerations
- reflex increase in HR due in increased O2 demand and implies intact CNS
- less than 32 weeks, increase HR 10 BPM for 10 seconds
- 32 weeks and greater, increase HR 15 BPM for 15 seconds
Early decelerations
- start with initiation of contraction, bottom out at contraction peak, and end with contraction
- thought to be vagal response
- not associated with hypoxemia/acidemia
variable decelerations
- hypoxemic event
- > 15 BPM drop reaching peak in <30 seconds
- lasting at least 15 seconds but no more than 2 minutes
- possibly due to cord occlusion
- can result in secondary hypoxemia
late decelerations
- hypoxemic event
- symmetric, gradual decrease in HR
- onset at peak of contraction, nadir at contraction termination, termination after contraction ends
- during contraction lactic acidosis occurs
reestablish oxygen pathway
- correct maternal physiologic abnormalities
- examine cord
- maternal repositioning
- IV bolus
- amnionfusion
- O2
FHR category I
- baseline rate 110-160 BPM
- baseline variability moderate
- late/variable decelerations absent
- early decelerations present or absent
FHR category II
doesn’t fit into category I or III but need to monitor
FHR Category III
- increased presence of acidemia (have 60-90 minutes before onset)
- absent variability and any of the following
- recurrent late decelerations, recurrent variable decelerations, bradycardia, sinusoidal pattern
neonatal resuscitation
- suction mouth/airway
- stimulate breathing with rubbing
- pulse <60 = compressions
- pulse 60-100 = stimulate
- pulse >100 = good
vacuum assisted delivery
- amount of traction limited by suction, too much acceleration results in pop-off
- if more than 3 pop-offs without progress then attempts abandoned
- preferred to C-section
cesarean
- low transverse hysterotomy best healing and lowest rupture risk
- pfannensteil most common laparotomy
fetal survival by week
- 23 weeks 20-30%
- better survival at 26 weeks
- 34 weeks = low complication
- 37 weeks = home with mom
preterm labor causes
- # 1 risk factor is preterm in previous pregnancy
- infection
- vascular disorder
- decidual senescence
- uterine overdistension
- decline in progesterone activity
- cervical disease
- breakdown of maternal fetal tolerance
- stress
signs of preterm labor
- pelvic or lower abdominal pressure
- constant low, dull backache
- mild abdominal cramps or regular consistent contractions
- change in vaginal discharge
- blood vaginal discharge is a late but specific sign
fetal fibronectin
- negative = just contraction
- positive = delivery likelihood in 2 weeks 50%
preterm labor prevention
progesterone
preterm labor management
- celestone steroid injection for lung development (#1 intervention)
- PCN/ampicillin for GBP
- Mag to prevent contractions
premature rupture of membranes diagnosis
Has to be before 37 weeks
- visualize fluid with speculum
- amniotic pH approximately 7
- fern test (not all fluid will fern)
premature rupture of membranes complications
- # 1 complication = labor
- chorioamnionitis (no matter fetal age have to deliver if mom infected)
- if little fluid physical deformities
- cord prolapse
preterm rupture of membranes management
- similar management to preterm labor if <34 weeks
- check temp/vitals/contractions/ABD pain
- regular contractions = short delivery
antepartum hemorrhage causes
- labor/PPROM = #1 reason
- placenta previa
- placental abruption
- uterine rupture
- vasa previa
placenta previa
- placenta covers the cervix and must have C-section (36 weeks for most)
- diagnosis with sonogram
- painless bleeding
placental abruption
-painful bleeding
placental abruption risk factors
- HTN
- age >35
- multiple births
- smoking
- cocaine
- ABD trauma (watch for 24 hours)
placental abruption class 1
- 0-10% separation
- minimal bleeding/pain
- normal vitals, coags, fetal heart tones
-if <34 weeks consider expectant management and steroids; gentle induction
placental abruption class 2
- 10-40% separation
- minimal to moderate bleeding
- normal vitals
- pain/contractions
- normal coags
- abnormal fetal heart rate tracings
- cesarean immediate
placental abruption class 3
- 50% or greater separation
- 1 liter blood loss
- hypotension
- hypertonic uterus
- DIC
- fetal demise
- resuscitation, avoid c-section, induce labor, prepare for massive post partum hemorrhage
uterine rupture
- risk factors: uterine scarring, obstructed labor, uterine trauma
- prolonged decelerations
- can be stitched back together, but usually hysterectomy performed
vasa previa
- fetal vessels go over cervix
- can’t tell fetal blood from maternal
- C-section
post partum hemorrhage
- # 1 cause of maternal death
- 70% uterine atony
- 10% retained placenta
- 20% lacerations/uterine rupture
- <1% coagulopathy
post partum hemorrhage risk factors
- distended uterus (large baby, multiples)
- infection
- mag
- fibroids
- long labor
uterine atony Rx treatment
- prostaglandin
- ergot alkaloid
- TXA
uterine atony surgical treatment
- intrauterine balloon (24 hrs)
- stitch compression (few weeks)
- ligate uterine artery
- hysterectomy
- ligate internal iliac
- embolize uterine artery
retained placental tissue
- visualize with ultrasound
- treat with D and C
- bleeding can start week or two later
morbidly adherent placenta
- risk factor uterine trauma
- standard treatment hysterectomy
genital tract trauma
- perineal laceration
- cervical laceration (not common)
- hematoma
-risk factors: macrosomia, episiotomy, forceps and vacuum delivery
uterine inversion
huge vagal response
shoulder dystocia
- Erb’s palsy
- anoxic injury
- risk factors: macrosomia, gestational diabetes, forceps use
pre-eclampsia
blood pressure >140/90 with at least 300 mg protein without end organ damage
pre-eclampsia with severe features
BP>160/110 or with end organ damage
superimposed pre-eclampsia
- worsening HTN, interval development of proteinuria, development of severe features
- systolic increase 30 points
- diastolic increase 15 points
signs of end organ damage
- headaches (seizure warning)
- scotoma, vision changes (seizure warning)
- hyperreflexes
- seizure
- cerebral edema
- stroke
- death
liver end organ damage
- microangiopathic hepatitis
- HELLP syndrome
- stretching Glisson’s capsule (RUQ pain)
- subcapsular hematoma
- liver rupture
- acute fatty liver of pregnancy (hypoglycemia)
renal end organ damage
- proteinuria
- azotemia (elevated BUN and creatinine)
- oliguria/anuria
cardiopulmonary end organ damage
- HTN
- left ventricular failure
- pulmonary edema
- peripheral edema
hematologic end organ damage
- thrombocytopenia
- hemolysis
- DIC
uteroplacental end organ damage
- chronic HTN leads to placental vascular disease and infarction
- acute HTN leads to abruption
- fetal growth restriction
- oligohydraminos
- fetal demise
intrapartum pre-eclampsia management
- mag for severe
- steroids for <34 weeks
acute HTN emergency
- BP >160/110 for >15 minutes
- labetalol and hydralazine
- goal is BP <160/110
eclamptic seizure phases
- facial automatisms
- tonic/clonic seizures
- post-ictal
don’t abolish the seizure with benzos, give mag
isoimmunization
-Rh negative mother and Rh positive fetus
fetal hydrops
- liver and high output cardiac failure secondary to severe anemia
- ascites, pleural effusion, pericardial effusion, skin edema
isoimmunization surveillance
- referral at antibody titer > 1:8
- kell always gets referral
- check blood viscosity as hemoglobin proxy (decreased = anemia)
isoimmunization prevention
- RhoGam (dose good for 12 weeks)
- give with any vaginal bleeding, at 28 weeks, and at delivery if baby Rh positive
fetal growth restriction
- potential harbinger of fetal demise
- risk factors: radiation, drugs, alcohol, multiples, placental infarction, aneuploidy
- food intake <1000 cal/day for growth restriction
fetal growth restriction diagnosis
- typically diagnosed by fundal height
- some may need serial ultrasounds
post maturity syndrome
- thin
- reduced subQ fat
- low BG
Breech presentation
- Frank can deliver vaginally, complete/incomplete cant
- complications
1. cord prolapse
2. head entrapment
3. nuchal arm
4. head deflexion and spinal cord injury
5. hypoxemia
vaginal breech delivery requirements
- frank breech
- flexed head
- normal size
- experienced provider
- capacity for emergency c-section
2nd twin smaller than 1st
multiples
more likely after age 35
multiples complications
- increased pre-eclampsia
- increased hyperemesis
- increased gestational diabetes
- increased low back/pelvic pain
monochorionic/diamniotic
- twins vessels can join
- twin twin transfusion syndrome
monochorionic/monoamniotic
-cords can get tangled up
