assessment of fetal growth
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ESTIMATING FETAL GROWTH
McDonald’s Rule
Method of determining fetal growth by measuring the fundal height,
The distance from the fundus to the symphysis pubis in centimeters is equal to the week of gestation between 20th and 31st week of pregnancy.
Fundal height greater than the standard: Multiple pregnancy Miscalculated due date Large-for-gestational-age infant Hydramnios Hydatidiform mole
Fundal height less than standard Failure to thrive Miscalculated due date Presence of anomaly
Typical Fundal Milestones 12 weeks
Over the symphysis pubis 2o weeks
At the level of the umbilicus 36 weeks
At the level of the xiphoid process
ASSESSING FETAL WEL-BEING
FETAL MOVEMENT
QUICKENING 18 – 20 weeks AOG
Varies especially in relation to sleep cycles of the fetus and mother activity during observation time.
SANDOVSKY METHOD Ask mother to lie in a left recumbent
position after a meal and record how many fetal movements she feels over the next hour
Normal: movement twice every 10 minutes or an average of 10 – 12 times an hour
CARDIFF METHOD Count-to-ten method The mother records the time interval it
takes for her to feel ten fetal movements Normal: 10 fetal movements in 1 hour
FETAL HEART RATE
Normal: 120 – 160 beats per minute Can be heard as early as 10th – 11th
week of pregnancy
NONSTRESS TESTING Measures the response of fetal heart
rate to fetal movement When a fetus moves, the fetal heart rate
should increase about 15 beats per minute and remain elevated for 15 seconds. It should decrease to its average rate again as the fetus quiets.
If no increase in beats per minute is noticeable on fetal movement, poor oxygen perfusion of the fetus is suggested
Results: Reactive: if two accelerations of fetal
heart rage lasting for 15 seconds occur after movement
Non-reactive: no accelerations occur with the fetal movement
Contraction Stress Testing Negative (normal): when no fetal
heart rate decelerations are present with contractions
Positive (abnormal): when 50% or more of contractions cause a late deceleration and continues after the contraction)
Comparison between non-stress test and Contraction Test
ASSESSMENT NONSTRESS CONTRACTION
What is measured Response of fetal heart rate in relation to fetal movement
Response of fetal heart rate in relation to uterine contractions porduced by nipple stimulation
Normal findings Tw0 or more accelerations of fetal heart rate of 15 bpm lasting 15 seconds or more following fetal movements in a 20-min period
No decelerations with contractions
ASSESSMENT NONSTRESS CONTRACTION
Safety considerations Woman should not lie supine to prevent supine hypotension syndrome
In addition to supine hypotension sydrome, observe woman for 30 min afterward to see that contractions are quiet and preterm labor does not begin
ULTRASOUND
Response of waves against objects Uses:
Diagnose pregnancy Confirm the presence, size, and location
of the placenta and amniotic fluid Establish that the fetus is growing and
has no gross defects
Establish the presentation and position of the fetus
Gender determination Predict maturity by measurement of
biparietal diameter. Discover complications of pregnancy Detect retained placenta.
Nursing Responsibilites
Explain procedure and give assurance Mother should have a full bladder
Instruct mother to drink a full glass of water every 15 minutes beginning an hour and a half before the procedure
Instruct mother not to void before the procedure
Place mother in supine position with abdomen exposed Place a towel under the right buttocks
Make sure that the gel used is room temperature or warmer
ELECTROCARDIOGRAPHY
Fetal HCG may be recorded as early as the 11th week of pregnancy
Used when a fetal heart anomaly is suspected
Magnetic Resonance Imaging(MRI)
Has the potential to replace or compliment ultrasound as a fetal assessment technique
Helpful in assessing complications such as ectopic pregnancy or trophoblastic disease
MATERNAL SERUM ALPHA-FETOPROTEIN
Alpha-fetoprotein A substance produced by the fetal liver that
is present in amniotic fluid and maternal serum
Abnormally high levels Indicates open spinal (neural tube defects)
or abdominal defects
Abnormally low levels Indicates chromosomal defects
AMNIOCENTESIS
Aspiration of amniotic fluid from the pregnant uterus for examination.
Done 12th – 13th week of pregnancy
Amniocentesis gives information of the following: Color of the amniotic fluid
Normal: color of water; slightly yellow late in pregnancy
Strong yellow color: blood incompatibility
Green: meconium staining
Lecithin/Sphingomyelin Ratio Protein components of surfactant Normal: 2:1
2:5 or 3:1 in patients with diabetes
Phosphatidyl Glycerol and Desaturated Phosphatidylcholin Also found in surfactant Presence indicate mature lung function
Bilirubin Determination Bilirubin is present if there is blood
incompatibility Chromosome Analysis
Determination of chromosomal diseases Fetal Fibronectin
A glycoprotein that plays a part in helping the placenta attach to the uterine decidua
Presence indicate damage to fetal membranes
Inborn Errors of Metabolism
Alpha-fetoprotein
Complications: Hemorrhage from penetration of the
placenta Infectionof amniotic fluid Puncture of the fetus
Preparation: Ask woman to void Place patient in supine position exposing
abdomen Take baseline maternal bp and FHB
Post-procedure Let woman rest quietly for about 30
minutes Assess FHB and presence of uterine
contractions If woman has Rh-negative blood,
Rho immuno globulin may be administered
PERCUTANEOUS UMBILICAL BLOOD SAMPLING
AKA Cordocentesis or Funicentesis Aspiration of blood from the
umbilical vein for analysis Ultrasound guided procedure
Includes: CBC Direct Coomb’s Test Blood gases Karyotyping
Kleihauer-Betke Test Test to determine if sample is fetal blood
Post-procedure RhIG may be given to Rh negative mothers
AMNIOSCOPY
Visual inspection of the amniotic fluid through the cervix and membranes with an amnioscope
Use: detect meconium staining
FETOSCOPY
Visualizing the fetus by inspection through a fetoscope
Uses: Confirm the intactness of spinal column Obtain biopsy samples of fetal tissues
and blood samples Perform elemental surgery
BIOPHYSICAL PROFILE
Combination of 4 – 6 parameters into one assessment Fetal breathingmovement Fetal movements Fetal tone Amniotic fluid volume Placental grading Fetal heart activity
AKA fetal Apgar More accurate in predicting fetal
well-being than any single assessment
Each parameter has a potential score of 2
Interpretation: 8 – 10: fetus is doing well 4 – 6: fetus in jeopardy
Biophysical Profile Scoring
ASSESSMENT INSTRUMENT CRITERIA FOR A SCORE OF 2
Fetal Breathing Sonogram At least one episode of 30 sec of sustained fetal breathing movements within 30 min of observation
Fetal Movement Sonogram At least three separate episodes of fetal limb or trunk movement within a 30-min observation
Fetal Tone sonogram The fetus must extend and then flex the extremeties or spine at least once in 3o minutes
ASSESSMENT INSTRUMENT CRITERIA FOR A SCORE OF 2
Amniotic fluid Volume
Sonogram A pocket of amniotic fluid measuring more than 1 cm in vertical diamter must be present
Placental Grade
Sonogram Placenta is grade 3; grading is based on structure and amount of calcium present
Fetal heart reactivity
Nonstress test Two or more fetal heart rate accelerations of at least 15 beats/min above baseline and of 15 sec duration occur with fetal movement over a 20-min time period