R 4

1
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• R 4 ???

2
Screening for neural tube defects and Down
syndrome

• Screening identifies individuals whose risk is
  high for further evaluation.
• Maternal serum AFP screening 15-22 wks
• A confirmed increase in maternal serum AFP to
  greater than 2.0 to 2.5 MOM indicates increased
  risk for a fetal NTD or other structural anomaly
  and warrants further evaluation.

3
Elevated levels of AFP

• Neural tube defects
• Esophageal or intestinal obstruction
• Cystic hygroma
• Abdominal wall defects-omphalocele, gastroschisis
• Urinary obstruction
• Renal anomalies- polycystic or absent kidneys

• Low birth weight
• Oligohydramnios
• Multifetal gestation
• Decreased maternal weight

4
Biochemical screening for Down syndrome

• Down syndrome most common cause of congenital
  mental retardation VSD, anterior abdominal wall
  defects. Typical faces.
• Combination of maternal age, hCG, AFP and uE3(
  unconjugated estriol)
• DS screening was based on maternal age alone and
  women aged 35 years and over were offered
  amniocentesis.
• Utilizes two analytes( hCG?, AFP?)double test
• Triple test high hCG, low AFP, and low uE3

5
Ultrasonography

• The mid-trimester anomaly scan for structural
  abnormality at 18-20 wks.
• Cardiac defect Four-chamber view identify 60 of
  severe lesions and a complete fetal cardiac scan
  identifies 75 of all cardiac abnormalities.
• NTD 95 of all spina bifida The recognized
  association of frontal bone scalloping( lemon
  sign) and abnormally shaped cerebellum( banana
  sign) aids the detection of neural tube lesions.

6
Ultrasonography

• Gastrointestinal abnormalities anterior
  abdominal wall defect( omphalocele and
  gastroschisis) at the mid-trimester scan
• obstruction and atresia is more often diagnosed
  in late second trimester or the third trimester
  because of polyhydramnios or an incidental
  finding of dilated loops of bowel.
• Thoracic abnormalities congenital diaphragmatic
  hernia may be diagnosed in the second trimester
  but is usually more apparent in the third
  usually left-sided.

7
Nuchal fold translucency

• Edema of the fetal neck, detectable in the first
  trimester by ultrasound, is associated with
  cardiac defects, Down syndrome, and other
  trisomies.
• Performed between 10 and 14 wks.
• Training of personnel and scanning time.

8
Amniocentesis

• Done between 15 and 20 wks amniotic fluid
  contains fetal cells shed from the gut and skin.
• Chromosomal analysis most commonly Down syndrome
  testing for maternal age, high risk serum tests
  and ultrasound markers.
• DNA analysis for genetic disease.
• Enzyme assays for inborn errors of metabolism.
• Investigation of fetal lung maturity (
  lecithin/sphingomyelin ratio or presence of
  phyophatidyl glycerol)
• Bilirubin ( for rhesus iso-immunization)

9
Amniocentesis

• The main risk miscarriage( lt1 procedure-related
  risk)
• Minor complications transient vaginal spotting,
  or amniotic fluid leakage(1), chorioamnionitis.
• The risk is higher when the procedure is
  performed at 14 wks or less( early
  amniocentesis).
• Needle injuries are rare, especially when
  real-time scanning is used.
• Culture failure is rare with a rate of less than
  0.5. Maternal cell contamination occurs in less
  than 0.2

10
Chorionic villus sampling

• CVS is performed at 10 to 13 wks allows earlier
  and safer methods of pregnancy termination when
  they are abnormal.
• Indications
• Karyotyping when ultrasound findings suggest
  aneuploidy.
• DNA analysis, particularly for haemoglobinopathies
  and recessive or X-linked disorders
• Complications
• Pregnancy loss- 2-3
• Maternal cell contamination lead to false
  negative results
• Limb reduction deformities before GA 9 wks.

11
Fundal symphyseal height

• A useful screening method for detection of the
  baby that is small or large for gestation.
• Third trimester approximate to the number of the
  gestation. The variation is 2 from 20-35 wks, 3
  from 36-38 wks, and 4 after that.
• Further investigation
• Limitation multiple pregnancies, maternal
  obesity, or polyhydramnios.

12
Fetal movement chart

• The presence of fetal movement is a sign of fetal
  well-being and occurs in a cyclical pattern.
• High risk pregnancies and those where a
  subjective reduction in movements has already
  been reported, the use of fetal movement charts(
  defining normality as 10 movements per day) may
  be of some benefit.

13
Cardiotocography

• Monitoring fluctuations in fetal heart rate over
  time and correlating this with any uterine
  activity. ( after 32 weeks)
• Non stress CTG
• baseline 110-160 beats/min with
• short-term viability around that baseline of
  between 5 and 25 beats/min.
• At least two accelerations should occur within
  each 20 mins( a rise of at least 15 beats lasting
  for 15 seconds).
• No deceleration from the baseline.

14
Cardiotocography

• Useful means of excluding current fetal hypoxia
  and acute compromise.
• The intermediate and long-term prognostic value
  of CTG is poor.
• Not be reactive hypoxia, anemia, infection,
  medication, cerebral hemorrhage, maternal
  metabolic disturbance, chromosomal or congenital
  malformation.