Ob-Fetal Monitoring

Front 1

How has continuous electronic fetal monitoring affected deliveries?

Back 1

It has increased the incidence of primary c-sections for fetal distress.

Front 2

Approach to interpretation of intrapartum fetal monitoring?

Dr C Bravado (pneumonic)

Back 2

DR: determine risk.
C: Contractions.
BRA: baseline rate (fetal monitor strip).
V: Variability.
A: accelerations (normal during fetal stimulation).
D: decelerations (can be sign of distress).
O: overall assessment.

Front 3

**2 types of electronic monitoring of FHR?

Back 3

*External (indirect) : detected through abdominal wall w/ transducer (CTG cardiograph) that emits ultrasound.
Uterine contractions also detected.

*Internal: bipolar spiral electrode attached to fetal scalp which detects peak R wave voltage of fetal ECG.

Front 4

2 forms of uterine contraction monitoring?

Back 4

External tocodynamometer.
Internal uterine pressure catheter (IUPC). Calculated in Montevideo units. Calc'd by increases in uterine pressure above baseline (8-12 mmhg) mltplied by contraction frequency per 10 min.

Front 5

*Process of uterine contractions?

Back 5

Increase in 1st stage of labor progressively and in intesnity from 35 mmhg to 50.

Frequency increases from 3 to 5 contractions per 10 min.

In Second stage: further increase to 80-100 mmhg and frequency of 5 to 6 per 10 min.

Front 6

10 high risk indications for continuous fetal heart rate monitoring?

Back 6

Maternal illness: GDM, HTN, asthma.
Multiple gestation.
Post-dates.
IUGR.
PROM.
Congen malformations.
3rd trimester bleeding.
Induction/ augmentation of labor.
Preeclampsia.
Psychosocial risks: no prenatal care, tobacco, drugs.

Front 7

**How is fetal distress/ hypoxia determined?

Back 7

Detected through changes in FHR and fetal blood pH.

Front 8

5 types of fetal distress?

Back 8

-Hypoxemia: decreased O2 in blood.
-Hypoxia: decreased O2 in tissue.
-Acidemia: increased H+ in blood.
-Acidosis: increased H+ in tissue.
-Asphyxia: hypoxia w/ metabolic acidosis.

Front 9

2 major neuro abnormalities associated with fetal distress?

Back 9

CP and MR. May not be noticed at birth.

Felt that 20-40% neuro disoders influenced by intrapartum events.

Front 10

*Pathophys of fetal hypoxia/ stressed fetus.

Back 10

Decreased perfusion d/t impaired uterine or umbilical blood flow --> decreased transfer of O2 to fetus --> accumulation of CO2.
- Increased CO2 --> similar to adult resp acidosis.
- Continued hypoxia --> buildup of organic acids.
- Accumulation of pyruvic and lactic acids --> metabolic acidosis.
- Transient decreases in fetal or uterine perfusion --> resp acidosis. Prlonged or severe decrease in perfusion --> resp and metabolic acidosis.
- fetal o2 deprivation --> bradycardia.

Front 11

*Best way to monitor for fetal distress?

Back 11

Continuous FHR monitor,

Fetal scalp capillary blood sampling --> fetal blood pH.

Front 12

*Definition of baseline fetal heart rate?

Back 12

Lasting greater than or equal to 10 min.
Beat to beat variability may be present.

*Normal: 120-160

Front 13

*Rates for tachycardia, suspicious tachy, pathological pattern?

Back 13

Tachy: >160.

Suspicious tach: 161-170.

Pathological: >170

Front 14

*MCC of fetal tachycardia?

Others?

Back 14

**Maternal fever.

Asphyxia,
infection,
prematurity,
drugs (ritodrine and atropine),
fetal stimulation,
arrhythmias,
materinal anxiety,
maternal thyrotoxicosis,
idiopathic.

Front 15

Definition of fetal bradycardia?

Back 15

<120 for > 10-15 min

Front 16

**6 causes of fetal brady?

Back 16

Asphyxia (sudden or profound),
Drugs,
Reflex (pressure on head)
Arrhythmias,
Hypothermia,
Idiopathic

Front 17

**What is beat to beat variability?

Back 17

Continuous interaction of autonomic nervous system (symp and parasymp) to adjust FHR for changes in metabolism and hemodynamic. It's an important index of fetal CNS integrity.

Front 18

**What is the single most important characteristic of baseline FHR and indicator of fetal status/ well being?

Back 18

Beat to beat variability (BTBV)

Front 19

**What is the single most reliable sign of fetal compromised?

Back 19

Prolonged diminished beat to beat variability

Front 20

**What is short term variability? (STV)

Back 20

Variation in amplitude seen on beat to beat basis, normally 3-8 bpm. Roughness (STV present) or smoothness (STV absent) of FHR tracing.

May be decreased/ absent d/t alterations in CNS or inadequate fetal oxygenation. Measured only by fetal scalp electrode.

Front 21

**What is long term variability? (LTV)

Back 21

Irregular, crude wave like (oscillatory) pattern with a cycle of 3-6 cycles per min and an amplitude of 5-15 bpm.

Results in waviness of baseline.

Can be measured by doppler or fetal scalp electrode.

Front 22

*What is good variability?

Back 22

Usually predicts good fetal outcome.

Suggestive of adequate fetal CNS oxygenation.

Front 23

*What is decreased variability?

Back 23

May be sign of loss of autonomic control of FHR.

*Decreased BTBV is diagnosed if short term variability is absent and there is less than two cyclic changes/ minute of long term variability.

Front 24

*Causes of decreased BTBV?

Back 24

Fetal asphyxia &/or acidemia,
Drugs,
Prematurity,
Fetal tachy,
Phys: fetal "sleep states"
Fetal cardiac and CNS abnorm,
Arrhythmias,
Prolonged contractions (hypertonus),
Maternal acidemia

Front 25

**What does NO BTBV mean?

Back 25

Acidosis and fetus must be delivered immediately!

Front 26

What causes increases in beat to beat variability?

Back 26

Mild fetal hypoxemia

Front 27

*Sinusoidal patterns?

Back 27

Cause unknown.
Rate 120-160 but there is smooth undulating pattern of 5-10 bpm in amp and shortened short term variability.

Assoc w/ extreme fetal jeopardy (Rh isoimm, fetal anemia).
Also seen after giving narcs to mother.
Prob sign of fetal compromise.

Front 28

*What is reactivity?

Back 28

Response of healthy fetus when stimulated.
Usually see transient increase in variability or baseline acceleration (10-15 bpm).
Stim can be external (sound, scalp stim) or internal (spontaneous fetal movement).

Front 29

*Definition of FHR accelerations?

Back 29

Increased FHR above baseline of at least 15 bpm, usually 15-20 seconds duration and assoc w/ intact fetus, unstressed by hypoxia and acidemia.
Reassuring and usually benign.

Examples: stim of fetal scalp by exam, sounds.

Front 30

*Definition of FHR deceleration?

Back 30

4 patterns based on configuration of wave form and timing of decel in relation to uterine contraction.

Front 31

*3 effects of decelerations on FHR?

Back 31

Severe: change > 60, lasting 1 min OR hr <90 - BAD sign!

Mild: Change < 20. Not nec bad.

Moderate: Between mild and severe. Can be bad.

Front 32

**What is early deceleration?

Back 32

One of the patterns of decel.
Slowing of rate, but never <100.
Normal, usually occur w/ contraction and is proportional to contraction strength.

Can occur w/ fetal head compression.
Begin at onset of contraction, lowest point at peak of contraction, return to baseline after contraction:
"Mirror image" of uterine contraction

Front 33

Intervention for early deceleration?

Back 33

none

Front 34

*What is late decelerations?

Back 34

One of the patterns of decel.
Usually in assoc w/ acute or chronic UTEROPLACENTAL VASCULAR INSUFFICIENCY.
Starts after peak and extends past length of uterine contraction, with often a slow return to baselin.
Caused by hypoxemia, direct myocardail depression or both.
May be assoc w/ mixed resp and metab acidosis.
Increased in preeclampsia, htn, dm, iugr, other assoc w/ chronic placental insuff.
Seen w/ abruptio placentae, maternal hypotension from anesthesia, excessive uterine activity.

Front 35

Interventions for late decels?

Back 35

Change position to lateral recumbent.
Give O2.
Stop Oxytocin.
Give IV fluid.
Give IV tocolytic.
Monitor BP.
If decels last > 30 min, get fetal scalp, blood pH and consider c-section.

Front 36

*What are variable decelerations?

Back 36

Type of decel pattern.
Can be mild, mod, severe.
D/t cord compression and/or head compression. If recurrent, suspect cord around neck or udner arm.

Slowing of HR inconsistently. May start before, during or after contraction.
Variable location, pattern, cause. Often <100 bpm, then rapid return to baselin.
Often assoc w/ oligohydramnios +/- ruptured membranes.
Causes short term resp acidosis.
May be assoc w/ profound combined acidosis if prolonged and recurrent.

Front 37

*What is the most common periodic FHR pattern?

Back 37

Variable decelerations

Front 38

Intervention of variable decelerations?

Back 38

Amniofusion - infuse normal saline into uterus through IUPC to alleviate cord compression.

Change maternal position to side/ trendelenbur position.

Deliver fetus by c-section.

Front 39

*What is prolonged decelerations?

Back 39

Decel pattern.

Isolated decels lasting 90-120 seconds or more.

Causes: prolonged umbilical compression, profound placental insuff, sustained head compression.

Front 40

Things that we do that can cause fetal distress?

Back 40

1.Maternal position. Uterus obstructs blood flow in great vessels --> decreased placental perfusion and fetal distress. **Relieve w/ lateral recumbent position.
2. Oxytocin stimulation: late decel and decreased placental perfusion. Minimize by using infusion pump and internal pressure catheter.
3. Peridural anesthesia. smpathetic block decreases veous return: decreased uroplacental perusion and late decels.

Front 41

**What is fetal scalp blood sampling?

Back 41

pH: gold standard for determining well being.
- normal: 7.25-7.35 during first stage of labor.
- **<7.2 = significant asphyxia, 7.2-7.24 = pre-acidotic.
- Low or norm pH, do repeat in 15-30 min

Front 42

Complications of scalp pH (not common)?

Back 42

Infection,
Occasional bleeding (sinus),
DIC - GBS
ITP

Front 43

Way to improve fetal oxygenation?

Back 43

Give 02 to mom.

Front 44

What is amnionfusion?

Back 44

Infusion of fluid into amniotic cavity through dilated cervix.

Relieves pressure on umbilical cord.

Front 45

Definition of postdates?

Back 45

>42 weeks.

Approx 10% do this.

Front 46

**Major concern in postdates?

Back 46

Fetal compromise d/t placental insufficiency from placental aging.

Front 47

*What is often responsibility for perinatal morbidity and mortality in postdates?

Back 47

Asphyxia.

Normally there is little growth post term.

Front 48

What is seen in dysmaturity sundrome (post-maturity syndrom) - babies that are postdates?

Back 48

Loss of subcu fat, growth retardation --> elderly appearance.
Dry, wrinkles, cracked skin.
Meconium staining skin, membranes and cord --> resp distress from mechanical obstrcution of small and large airways and chemical pneumonitis.
Long nails.
Unusual degree of alertness.
25% macrosomic (>4000g)

Front 49

Macrosomic babies (>4000) are at risk for what?

Back 49

Altered gluc d/t placental dysfunction (hypoglycemia).
Hyperbilirubinemia.
Maternal trauma.
Increased incidence of birth trauma: shoulder dystocia, clavicle fx, erbs palsy, c-section d/t cpd.

Front 50

*How prevalent is meconium aspiration?

Back 50

13-15% term pregnancies

Front 51

Biochemical evaluation of postdates fetus?

Back 51

Maternal urinary estirol: can indicate fetal compromise. Serial values over days or week most helpful. < 12 mg/24 hrs --> fetal jeopardy. Normal values does not r/o fetal distress and decreased levels can indicate other dz.

hCS/HPL: hormone from placenta. Level proportional to wt of fetus and placenta.

Front 52

*What is a non-stress test?

Back 52

Non-invasive test of fetal activity.
Correlates w/ fetal well being.
Watch fetal heart acceleration during fetal movement.
Can be subjective.

Procedure: mom in left lat supine. Continuous FHR tracing using doppler. HR changes that result from fetal movements are determined.

Front 53

*Reactive test (R-NST) non-stress test?

Back 53

Normal baseline HR, normal variability and at least 2 accelerations in 20 min, each lasting > 15 sec and peaking at 15 above baseline.
Reactive = normal!
Repeated q 3-4 days depending on situation.

Front 54

What is a non-reactive NST?

Back 54

Interpret in light of getstation age.

Associated w/ poor perinatal outcome in 20%.
Non-reactive test must be immed followed w/ more work-up like biophysical profile.

Front 55

**What is a contraction stress test (CST)?

Back 55

Test of FHR in response to artificially induced uterine contractions.
Min of 3 contractions in 10 min required.

*Indirect measure of placental function (test for uteroplacental dysfunction).
*Can be performed when first NST is non-reactive.
Negative CST: baseline FHR unchanged and NO FHR decels in response to contractions.
Considered reassuring.

Front 56

**Negative Contraction stress test?

Back 56

3 uterine contractions over 10 min w/ no evidence in FHR of late decels, severe variable decels or loss of beat to beat variability.

Usually predicts good outcome.
**25% false-pos rate.

Front 57

**Positive contraction stress test?

Back 57

Severe variable or late decels w/ >50% of contractions.

Assoc w/ adverse outcome in 35-40%.

Front 58

What does it mean if a contraction stress test is equivocal?

Back 58

Repeat in 24-72 hrs.

>80% of repeat tests will be neg.

Front 59

*What is biophysical profile?

Back 59

Uses US and Cardiotocography to ascertain fetal well being.

Front 60

5 components of biophysical profile?

Back 60

Reactivity (non-stress test).
Fetal breathing movements (chest wall).
Fetal tone (flexion/ extension of extremity).
Fetal activity (gross trunk of limb movements).
Amniotic fluid index.

Front 61

What is Amniotic Fluid index (AFI)?

Back 61

Calc of volume of amniotic cluid.

Maternal abd divided into quadrants. Using US, max vertical pocket of each quadrant measured in centimeteres and added.

Front 62

Normal amniotic fluid volumes?

Back 62

Max reached at 34-38 weeks (800-1000 ml).

After 38, fluid decreases.

By 42, fluid at 500 ml.

Front 63

What is oligohydramnios?

Causes?

Back 63

<5 amniotic fluid index.

MCC: ROM.
Assoc w/ IUGR in 60%.

Front 64

What is Polyhydramnios?

Back 64

>20 amniotic fluid index.

Or 2 liters.

Front 65

*How is biophysical profile scored?

Back 65

Each test given 0-2 pts for max of 10pts.
2 pts if variable is present or normal. 0 if absent.

*Amniotic fluid volume/ index is most important variable.
Normal: 8-10.
6 or less suspect for asphyxia and BPP should be repeated in 4-6 hrs or consider delivery.

Front 66

What is vibroacoustic stimulation?

Back 66

Response of FHR to vibroacoustic stimulus.

Acceleration on NST (>15 bpm for >15 sec) is pos.
Useful adjunct to decrease time to achieve "reactive" NST and decrease proportion of non-reactive NST at term, precluding need for further testing.

Front 67

What are fetal movements charts ("kickcharts")?

Back 67

Fetal movement decreases w/ advancing gestational age, oligohydramnios, smoking and metamethasone therapy.

Kickcharts involve counting all fetal movements in 1 hr or counting the time it takes the fetus to kick 10 times.
Do this twice daily.

In high risk pregs, can decrease perinatal mortality 4 fold.

Front 68

*Term for cervical cahnges?

Back 68

Ripening.

Oxytocin more likely to work if cervix is ripe.

Degress of ripeness quantified by Bishop score**

Front 69

**What is bishop score?

Back 69

0-3 points for each parameter:
- fetal station
- dilation
- effacement
- consistency of cervix
- position of cervix

Front 70

Bishop score in totally unripe cervix?

Back 70

0.

No dilation, no effacement, firm, posterior, -3 station.

Front 71

What does Bishop score of 8 mean?

Back 71

Ripe cervix

Front 72

What is oxytocin infusion used for?

Back 72

Induction.

Depends on condition of cervix. Unripe may not respond.

Front 73

What is Prostaglandin gel used for?

Back 73

Ripens cervix.

In US, only dinoprostone (PGE2) approved for ripening.

Apply to cervix day before attempting oxytocin induction.

Front 74

Side effects of Oxytocin?

Back 74

n/v
Uterine hyperstimulation
Uterine rupture

Front 75

Another method of induction?

Back 75

Laminaria Tents - from seaweed.

Front 76

*What is apgar score used for?

Back 76

Assessing fetal condition at 1 min and 5 min after birth.

Evaluates five signs of fetus status, assigning max of 2 pts each.

Front 77

*What are the 5 signs of fetal status in apgar?

Back 77

HR,
Resp,
Muscle tone,
Relfex,
Color

8-10 = good condition.
<8 = needs assistance or internvention.

Front 78

What is given to the new born if GC is possible?

Back 78

Eye meds - abx to prevent blindness

Front 79

What other med is often given at birth?

Back 79

Vitamin K: 1 mg IM or orally.

Front 80

Medications used for neonatal resucitation?

Back 80

Sodium bicarb (to counteract acidosis)

Epinephrine to stimulate heart.

Naloxone: d/t narcotic effect from mom.