Presentation on theme: "Fetal Health Surveillance (FHS): Part 3 – Antepartum Maternal Newborn Orientation Learning Module Reproductive Care Program of Nova Scotia, 2013 *FHS:"— Presentation transcript:
Fetal Health Surveillance (FHS): Part 3 – Antepartum Maternal Newborn Orientation Learning Module Reproductive Care Program of Nova Scotia, 2013 *FHS: Parts 1 and 2 should be viewed prior to review of this module
Objectives To review guidelines for recommended antepartum fetal health surveillance (FHS): Indications Methods: Fetal movement awareness and counting Non-stress test (NST) Biophysical profile (BPP) and modified BPP Uterine artery Doppler Contraction stress test Interpretation and recommended actions
Indications for Antepartum FHS With one exception, initiation of antepartum FHS is advised only when there are existing or developing risk factors for adverse outcomes. There is no evidence to support routine use of antepartum surveillance in uncomplicated pregnancies < 41+0 weeks gestation.
Indications Based on Previous Pregnancy Maternal: Hypertensive disorders of pregnancy (HDP) Abruption Fetal: Stillbirth Intrauterine growth restriction (IUGR) *full list SOGC guideline page S11
Current Pregnancy Indications Maternal: Postterm pregnancy (> 42+0 wks) Pre-pregnancy/insulin requiring diabetes Motor vehicle accident Hypertensive disorders of pregnancy (HDP) Morbid obesity Advanced maternal age Fetal: Suspected oligohydramnios or polyhydramnios Multiple pregnancy IUGR Decreased fetal movement *full list SOGC guideline page S11
Fetal Movement (FM) The only method of FHS recommended for all women, is maternal awareness of fetal movement. Normal fetal activity suggests a healthy, non- hypoxic fetus. Fetal movements are more frequent in the evening; best perceived when side-lying or semi- recumbent. Normal fetal activity – ≥ 6 movements in 2 hours
Recommendations about Fetal Movement Counting All healthy pregnant women should be informed of the significance of fetal movements (after 24 to 26 weeks gestation) and encouraged to perform a fetal movement count if they perceive decreased movements. In pregnancies with risk factors for adverse outcomes, daily monitoring of fetal movement starting at 26 to 32 weeks gestation is advised. If there are < 6 movements in 2 hours, further testing is recommended.
If < 6 Movements in 2 Hours…. Non-Stress Test (NST) Normal NST No Risk Factors Continue FM Counting Normal NST Risk Factors BPP or AFV in 24 hours Atyp. or Abn. NST* BPP (or CST) ASAP *Urgent delivery may be indicated
Non-Stress Test (NST) By definition, an NST is a fetal assessment without the ‘stress’ of labour. An EFM tracing of FHR and uterine activity is obtained for a minimum of 20 minutes; tocotransducer is always applied. An NST should be obtained only in situations of risk for adverse outcomes.
Normal NST Baseline within normal range – 110 to 160 bpm Moderate variability – 6 to 25 bpm No decelerations or occasional variable decelerations < 30 seconds At least 2 accelerations of at least 15 bpm lasting at least 15 seconds (≥ 32 weeks gestation) or at least 10 bpm lasting at least 10 seconds (<32 weeks gestation) in < 40 minutes
G1 36 Weeks Gestation NST due to Insulin Requiring Diabetes
Baseline 150 Accelerations
G2 with Bleeding at 29 Weeks
Twin Pregnancy at 35 Weeks
Atypical NST Baseline 100 to 110 bpm, > 160 bpm for < 30 minutes, or rising Minimal or absent variability for 40 to 80 minutes Variable decelerations lasting 30 to 60 seconds < 2 accelerations in 40 to 80 minutes
Abnormal NST Baseline 160 bpm for > 30 minutes or erratic Minimal or absent variability for > 80 minutes, marked variability for > 10 minutes, or sinusoidal Variable decelerations lasting > 60 seconds; late(s) 80 minutes
Recommended Actions Normal NST: Depending on the clinical picture, further investigation is generally not indicated. Atypical NST: Additional fetal assessment and a review of maternal and fetal health status is required.
Recommended Actions Abnormal NST: ‘Immediate further investigation’ is essential; urgent delivery may be indicated. ‘Clearly stated, readily accessible protocols identifying interdisciplinary team member responsibilities and actions must be in place’. (SOGC, 2007)
Biophysical Profile (BPP) Ultrasound assessment of 3 fetal ‘behaviors’ i.e. movements, breathing movements, and tone Ultrasound assessment of amniotic fluid volume (AFV) NST
Components of BPP ComponentCriteria 1.Movements≥ 3 body or limb movements 2.Breathing movements≥ 1 episode of > 30 seconds 3.ToneAn episode of extension with return to flexion of a limb or trunk or Opening and closing of the hand 4.AFV≥ 1 amniotic fluid pocket of 2 cm x 2 cm 5.NSTNormal Scoring each component: ‘0’ absent; ‘2’ present The total score is reported
Amniotic Fluid Volume (AFV) Amniotic fluid volume is a key component of the BPP. AFV is affected by the production and flow of fetal urine. Decreased amniotic fluid (in the absence of ROM, renal malfunction or obstructed urinary tract) will occur when blood is redistributed away from the kidneys in response to chronic hypoxia.
BPP Scoring A score of ≥ 8/10 is considered normal provided it includes ‘2’ for AFV. A score of 6/10 is considered equivocal (provided the score for AFV is ‘2’); further investigation is required. A score of ‘0’ for AFV or a total score of ≤ 4/10 is abnormal and associated with a high probability of fetal asphyxia; delivery will likely be indicated.
Practices Related to the BPP In some facilities, an NST is not routinely part of the BPP, provided a perfect score for all ultrasound components is achieved. –Score will be 8/8 A modified BPP involves an NST and the AFV component only.
Umbilical Artery Doppler Ultrasound measurement of the velocity of blood flow away from the fetus through the umbilical arteries into the placenta There is normally a positive flow toward a healthy placenta as resistance in the placental bed is lower than in the umbilical arteries. If resistance in the placenta is increased, blood flow is impaired and gas exchange between the placenta and fetus is compromised.
End-Diastolic Blood Flow Velocity Indirect assessment of resistance within the placental bed and overall functioning of the placenta Results: normal, reduced, absent or reversed Risk of perinatal mortality increases as arterial blood flow slows, stops or reverses.
Contraction Stress Test (CST) Oxytocin is administered until the woman experiences 3 contractions in 10 minutes, each lasting 1 minute. It is considered positive if there are late decelerations occurring with 50% of the contractions; negative if the tracing is normal without late decelerations. CSTs are rarely done because of the risk of tachysystole and options for ultrasound assessments that are more readily accessible.
In summary The only method of antepartum FHS recommended for all women is maternal awareness of fetal movement, with fetal movement counting if a decrease in movements is perceived. Other methods should be initiated only in pregnancies at risk for adverse outcomes. Each unit should have ‘clearly stated, readily accessible protocols identifying interdisciplinary team member responsibilities and actions’ related to results of antepartum FHS.
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