Antepartum Fetal Surveillance ‘HELLO BABY, HOW ARE YOU?’ Presented By: Janet L. Smith, RNC, BSN Author: Ruth Saathoff, RNC, BSN OBJECTIVES: At the end of this class the learner will be able to: Name 5 methods of monitoring the fetus for wellbeing Describe the physiology of maternal and fetal circulation in the relationship to fetal reserve. Identify the maternal and fetal conditions that indicate a need for fetal surveillance. Indications for Fetal Evaluation Maternal risk factors Pre-existing maternal disease Exposure to teratogens in 1st trimester Substance abuse Infertility or conception within 3 months of last delivery (cont.) Indications for Fetal Evaluation Maternal Factors (cont) History of OB complication • Oligohydramnios, Gestational Hypertension, etc. Previous pregnancy loss PROM > 24 hours Familial history of genetic abnormality Post dates Indications for Fetal Evaluation Fetal risk factors Prematurity SGA or LGA Intrauterine growth restriction (IUGR) Known anomaly History of IUFD Fetal cardiac arrhythmias Decreased fetal movement Why and When Why do we think of a well baby in terms of placental perfusion? Oxygen & nutrients are needed for fetus Risk factors may reduce delivery to fetus Good oxygen & nutrient delivery results in movement and growth When is surveillance started? When risk is present IDDM (type 1) - 32 weeks Previous loss - 34 weeks Patient: Kay Sarah Doc: I. Ben Cursed M.D. G 2 P1-0-0-0 Previous stillbirth @ 39 weeks Present gestation is 37 weeks Has been keeping a Fetal Activity Diary (FAD) since 36 weeks Now to begin surveillance with weekly NST Fetal Movement Counts FM indicator of intact Central Nervous System function First line defense to identify the fetus in trouble 30-50% of IUFD occur in women with no identifiable risk factors FAD Methods for Fetal Movement Counts Count-to-ten Counting after meals Evening monitoring Interpretation Report when criteria not met Report no movement over 8 hours Report sudden violent increase in fetal activity followed by cessation of movement Report changes in normal pattern of fetal movement Non-stress Test (NST) Fetal movement typically accompanied by FHR accels when CNS intact and with adequate oxygenation Procedure: Position sitting, semi-Fowler’s with tilt to either side Good quality EFM tracing for 20-40 min May monitor up to 60 min Interpretation What to look at (5 parameters) What’s the baseline? Is there variability present? Any uterine activity present? Any accels present? Any decels present? Assessment Baseline Variability Accelerations Uterine Activity Decelerations Fetal Movement Interpretation Reactive: 2 accels in 20 min. 15 bpm X 15 sec. 15 sec. from start of accel to end of accel 15 bpm at apex of accel gestation < 32 weeks • 10 bpm X 10 sec. • frequent decels of 10-20 sec. Interpretation Nonreactive: does not meet above criteria if not reactive in 60 min. unlikely to become so; call HCP isolated decels seen in as many as 33% Example at term Example 31 weeks Back to Ms. Sarah Her NST is reactive Anything else? Chart the 5 parameters on strip & chart Call HCP and report Schedule next appointment Continue FAD Retesting If no risk factors, unlikely to have FD in one week With risk factors, repeat 2 times a week If pregnancy status changes, repeat in 24-48 hours Patient: Ms. Hertzelot Doctor: I. Ben Cursed M.D. 37 weeks gestation G1 P0 Has not felt baby move for 8 hours Please do NST Assessment NST: Non-reactive after 40 min Possible causes: fetal sleep smoking before coming Maternal medications immature CNS fetal hypoxia Well, now what? Juice myth Do Fetal Acoustic Stimulation Test (FAST) Usually elicited after 28 weeks Can be done after 10 min of non-reactive pattern Handheld device generates a low frequency (82 decibels) vibro-acoustic stimulus Apply for 3-5 sec avoiding fetal head; may repeat X 2 at least 1 min apart May cause some level of stress Results of FAST Causes ‘Moro’ or startle reflex if CNS intact Increase in FHR 1 accel of 15 bpm over 2 minutes 2 accels of 15 bpm for at least 15 sec within 5 minutes of test Useful way to reduce number of nonreactive NST's Shortens testing time Vibroacoustic Stimulation Back to Ms. Hertzelot Well, now what? NST reactive with FAST Monitor until BL is restored Home with FAD Document on Strip and Chart Patient: Ms. Shirley I. M. Late Doctor: I Ben Cursed M.D. 40 & 5/7 weeks gestation Please do NST Results: NST: non-reactive FAST (or VAS): still non-reactive More monitoring: still non-reactive Well, now what? Options: Contraction Stress Test (CST) • assumes uteroplacental insufficiency will show hypoxia with late decels with contractions Biophysical Profile (BPP) • Ultrasound assessment of acute and chronic markers show good predictor of fetal well-being CST Modes Nipple stimulation (BST) • may be poorly received by patient • noninvasive IV oxytocin (OCT) • requires invasive procedure Spontaneous contractions Interpretation FHR response to stress of contractions 3 contractions lasting 40-60 sec. in 10 min. ‘Negative’ is absence of late decels (That’s good!) ‘Positive’ is presence of late decels (That’s bad!) > 50% of contractions--need to deliver ‘Equivocal’ is presence of some lates <50% of contractions Hyperstimulation or Unsatisfactory Results Considered testing failure and are not clinically useful ‘Suspicious’ Variable Decelerations Negative Positive – Late Decelerations Suspicious – Variable Decelerations Test Failure - UterineTachysystole BPP Parameters Fetal Tone (FT) (7-8wks) Fetal Movement (FM) (9wks) Fetal Breathing Movements (FBM)) Amniotic Fluid Index (AFI) > 6 cms NST (Accelerations 30-32 wks) Need high tech equipment/skilled technician Non-invasive, highly predictive (20-21wks) Scoring Biophysical Variable Fetal breathing movements Normal (Score = 2) 1 or more episodes of ≥ 20 s within 30 min Abnormal (Score = 0) Absent or no episode of ≥ 20 s within 30 min Gross body movements 2 or more discrete body/ limb movements <2 episodes of body/limb movements within 30 min (episodes of active within 30 min continuous movement considered as a single movement) Fetal tone 1 or more episodes of active extension with return to flexion of fetal limb(s) or trunk (opening and closing of hand considered normal tone) Slow extension with return to partial flexion, movement of limb in full extension, absent fetal movement, or partially open fetal hand Reactive FHR 2 or more episodes of acceleration of ≥ 15 bmp* and of >15 s associated with fetal movement within 20 min 1 or more episodes of acceleration of fetal heart rate or acceleration of <15 bmp within 20 min Qualitative AFV 1 or more pockets of fluid measuring ≥ 2 cm Either no pockets or largest pocket <2 cm in vertical axis in vertical axis Interpretation Scoring 10 point scale (if performed with a NST) 8-10 indicates fetus in good condition 6 indicates need to repeat in 4-6 hours <6 indicates need for delivery AFI < 6 cms indicates delivery Back to Ms. Late Well, now what? NST: non-reactive CST: negative BPP: 6/10 (FT-2, FM-2, FBM-0, AFI-2, NST-0) Report to HCP/document all findings Home with FAD Reschedule for repeat NST/BPP in 2-3 days Other Surveillances Amniocentesis Fetal lung maturity Testing- genetic, cultures, change in optical density Ultrasound Examination Uterine contents Fetal biometry / dating Fetal anatomic examination Other Surveillance Options Doppler Flow Studies Checks BP of uterine and placental vessels Associated with fetal growth deficiency Other Surveillance Options (cont’d) Chorionic Villus sampling early prenatal genetic studies References: American Academy of Pediatrics, American College of Obstetricians & Gynecologists, Guidelines for Perinatal Care (5th ed. 2002), Antepartum surveillance, pp. 89-107. AWHONN Fetal Heart Rate Monitoring Principles and Practices 4th Ed. Christensen FC, Olson K, Rayburn WF (2003). Cross-over trial comparing maternal acceptance of two fetal movement charts. Journal of Maternal-Fetal and Neonatal Medicine, 14(2), pp. 118-122. Devoe, L, Glob. libr. women's med., (ISSN: 1756-2228) 2008; DOI 10.3843/GLOWM.10210 Martin, E.J., Intrapartum Management Modules (3rd ed. 2002), Performing fetal surveillance testing, pp. 411-413. Mattson, S., Smith, J.E., Core Curriculum for Maternal-Newborn Nursing (3rd. ed.,2004), Clinical practice pp. 165-166. Simpson, K. R., Creehan, P.A., Perinatal Nursing (2nd ed., 2001), Fetal surveillance, pp. 147-154.