assessment of fetal growth

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