Chapter 29 MATERNAL-FETAL TESTING
McDonald’s Rule
 Estimation of fetal growth
 20 – 31 wks
 Fundus – symphysis pubis
 Cm = wks. gestation
Fetal Movement
 “Kick counts” – DFMC
 Less than 3/hr needs eval
 None for 12hrs – fetal alarm
 Sleep Cycle
Nonstress Test
 Response of fetal heart rate to fetal movement
 Reactive vs. nonreactive
 15 X 15/ 20
 Fetal sleep cycle
 VST Vibroacoustic stimulation
External Fetal Monitoring (NST)
Triple or Quad Screen
 MSAFP
 Unconjugated estriol
 Human Chorionic Gonadotropin (hCG)
 Quad screen also includes inhibin-A
Neural Tube Defects (NTD)
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Nonclosure of neural tube
Affects brain and spine
Spina bifida ( 50%)
o Occulta
o Cystica: myelomeningocele,myelocele
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Anencephaly (40%) most severe
o
Myelomeningocele
FETAL PROFILE OF ANECEPHALY
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Encephalocele (10%)
Dx: AFP in amniotic fluid, acetylcholinesterase
28 days¯ p conception,
o spina bifida occulta from incomplete closure of one or more vertbera
without protrusion of spinal cord or meninges
o may have dimple or depression, tuft of hair, port wine stain
o may have no neuro deficit X, foot weakness, bowel/bladder disturbance
Neuro deficit below level of contents in external sac in myelomeningocele, paralysis, incont. Clubfoot,
hydrocephalus (90%), poss. Mental retardation.
Rx: Surgery to close defect, can not reverse neuro def.
CAUSE: isolated birth defect, teratogen, multiple malformation, chromosomal T13 or 18. Lack of folic
acid. Inc in N and S Carolina
Maternal serum Alpha-fetoprotein (MSAFP)
 Produced by fetal liver
 Screening tool 16 –18 wks
 Correlate with gestational age, maternal age,weight, race, Type I DM
  in NTD, multifetal pregnancy, intestinal atresia
Contraction Stress Test (CST)
 FHR and UC monitoring
 Initiate UC via nipple stimulation or infusion of oxytocin
 Assess for uteroplacental insufficiency
 Positive, negative, suspicious
 Hyperstimulation
 Contraindications
 Persistent and consistent late decels occuring with> 50%UC’s is positive test
 Hyperstim. >90 sec or q. 2min
 Contraindications: PTL, Pl Pr, Pl abr, classical scar, etc
Chorionic Villi Sampling (CVS)
 Genetic/chromosomal testing
 Earlier diagnosis (10-12 wks) and rapid results but more risk that amniocentesis
 Transcervical or transabdominal
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o
RhOGam for Rh¯ mothers
Percutaneous Umbilical Blood Sampling (PUBS)
 PUBS = cordocentesis
 Direct access to fetal circulation
 Needle into fetal umbilical vessel
 Inherited blood disorders, isoimmunization, fetal infection, acid base, karyotyping, fetal blood type,
rbc and platelets
 Intrauterine transfusion
 Kleihauer-Betke
o to determine if blood is fetal in origin
 RhO Gam for Rh¯
 Done at 18 wks, need specialists
Amniocentesis
 Analysis of amniotic fluid
 Biologic: Chromosomes
 Chemical: AFP, bilirubin, lecithin/sphingomyelin (L/S) ratio (3rd trimester)
 After week 14 – 2nd trimester
 Complications < 1%
 After wk 14:uterus is abdominal organ, more amniotic fluid
 Dx: genetic, congenital (NTD), pulmonary maturity, fetal hemolytic disease
 how long does it take to get results?
 RhOgam for Rh¯ neg mothers
Ultrasound
 Use of sound waves to produce real time images in three dimension. When sound strikes an object,
echo is returned
 Transabdominal or transvaginal
o Transvag useful early on: ectopic pregnancies, monitor devel embryo, id abnormalities and est
GA
 Multiple indications and uses
 Limited or comprehensive
o Limited: confirm pregnancy, fetal viability, multipl gestation. presentation, locate placenta,
malformations, amniotic fluid vol.
o Comprehensive: abnl fetus, abnl exam, poly or oligo,elev AFP, Hx of abnl offspring
 Also needed for cvs, pubs, amnio.detect maternal abnl, est or confirm dates, IUGR, macrosomia, pl
previa, abrutio placenta, BPP, AF assessment, placental maturity,fetal well being
 Full bladder for abd US when it is an abdominal organ (after 1st trimester). Pelvic tilt for transv.
 p.819 for chart
 Multiple gestation
 FHR activity 6 –7 weeks by ehco
o
10 –12 weeks by Doppler
 GA determination :
o Gestational sac 8 wks
o CRL 7 – 12 wks
o BPD after 12 wks
o Femur after 12 wks
 Serial measurements in later gestational age 2, preferably 3 plotted against nl growth curvesbetw 2432 wks teilds est error of 10days +/_
 Fetal nuchal translucency (FNT) 10 - 14 wks
o Greater than 3mm – genetic disorder or anomaly
 Placental position and function
o Seen 14 – 16 wks low lying until 3rd trimester
o Graded 0 –3
o Calcium deposits/ postterm
Normal Nuchal Translucency
Abnormal Nuchal Translucency
Ultrasound Placenta
Ultrasound Fetal Head
Ultrasound Fetal Body
Ultrasound Fetal Head
Fetal US
US Placenta/UC
Fetal Growth
 Poor maternal weight gain
 IUGR
 Chronic infections
 DM
 HTN
 Macrosomic
 Symmetric IUGR reflects chronic or longstanding insult:low genetic growth, intrauterine infection,
malnutrition, smoking, chromosomal abnormality
 Asymmetric IUGR: placental insufficiency D/T HTN, CV, renal disease
 Macrosomic >4000gm, dystocia, traumatic injury, asphyxia. Infant diabetic mother, assymetric HC
nl, increased fat and muscle in shoulders and abd
Biophysical Profile
 Noninvasive dynamic fetal assessment
o Fetal breathing movements (FBM)
o Fetal movements
o Fetal tone
o Fetal Heart Rate (FHR)
o Amniotic fluid volume (AFV)
 Graded 0 - 10
 See handout
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