Assessment of Fetal Well-Being
Ultrasound • Definition -- an instrument which uses reflective sound waves as they travel in tissue to visualize structures in the body
Purposes of Performing an Ultrasound • Validate the pregnancy • Determine how advanced the pregnancy is • Detect congenital anomalies and problems • Localize the placenta • Assess fetal viability – heartbeat, breathing movements • Diagnose cardiac problems • Detect fetal presentation, number of fetus
Ultrasound • It is a non-invasive and painless procedure • Results are immediate • Allows the mother and family to “see” the baby
Ultrasound Nursing Care • Make sure that the patient has a full bladder • Place patient on back with a towel roll under one hip -- allowing better perfusion of the placenta • The test requires about 20 - 30 minutes
Alpha - Fetoprotein AFP • Measurement of a protein produced by the yolk sac and fetal liver. Main protein in fetal plasma. Diffuses from fetal plasma to fetal urine, excreted in amniotic fluid. • Measured via maternal serum or amniocentesis • Elevated levels of AFP may be indicative of open neural tube defects because the AFP leaks out of the fetal circulation into the amniotic fluid and chromosome abnormalities.
Chorionic Villi Sampling • Removal of small tissue specimen from the fetal portion of the placenta • Tissue obtained about 10-12 weeks gestation • Chromosomal studies performed
Chorionic Villus Sampling • Advantage – can be done earlier than an amniocentesis to detect problems. • Disadvantage – spontaneous abortion
AMNIOCENTESIS Collection of Amniotic Fluid for Testing
Amniocentesis • An invasive procedure • Requires a consent form to be signed • Performed about 14 - 16 weeks gestation • Patient must be informed of possible complications • Trauma • Infection • Hemorrhage
Amniocentesis • Preparation • Permits signed • Vital Signs and FHT’s • Abdominal prep and scrub • Procedure • Area of insertion is anesthesized and a needle inserted into the amniotic cavity and 5 - 30 ml of fluid withdrawn for analysis • Post care / Discharge Teaching • Vital signs and FHT’s normal • No leakage of fluid from site • Teach patient to report -- lack of fetal movement, discharge or bleeding, abdominal pain, or fever
Amniocentesis • Why is an Ultrasound performed as part of the procedure? • To detect placement of the placenta
AmniocentesisTests Performed Triple Test AFP hCG Unconjugated estriol Genetic studies Most commonly used to diagnose Downs Fetal Lung Maturity L/S ratio – lecithin-sphingomyelin ratio
L/S Ratio Lecithin / Sphingomyelin Ratio • Lecithin is a major constituent of surfactant. As surfactant increases in the lungs, the levels of lecithin should also increase. • Lecithin should become 2 - 3 times greater than sphingomyelin by about 35 weeks • Fetal maturity is attained when the L/S ratio is 2 : 1 Assesses Fetal Lung Maturity
Karotyping and Cell Enzyme Studies Determine sex of the fetus Normalcy of Chromosomes
Non-Stress Test NST
Non-Stress TestEvaluation of Fetal Status • Observation of fetal heart rate associated with fetal movement. • With movement of the fetus, the FHR should increase, or accelerate • This test is based on the knowledge that when the fetus has adequate oxygenation and an intact CNS, there are accelerations of FHR with movement.
Procedure for the NST • Electronic fetal monitor is applied • As the NST is done, fetal movements are documented • Compare the FHR with the fetal movements • Results: • Reactive -- two accelerations of 15 BPM lasting 15 seconds, associated with fetal movement. This is an indication of fetal well-being • Nonreactive-- no accelerations of FHR. Indication of need for further assessment
Non-Stress Test Example of a reactive non-stress test (NST). Accelerations of 15 beats per minute lasting 15 seconds with each fetal movement (FM). Top of strip shows FHR; bottom of strip shows uterine activity tracing. Note that FHR increases (above the baseline) at least 15 beats and remains at that rate for at least 15 seconds before returning to the former baseline.
Non-Stress Test Example of a nonreactive NST. There are no accelerations of FHR with FM. Baseline FHR is 130 beats per minute. The tracing of uterine activity is on the bottom of the strip.
NST Management Scheme ***If test is non-reactive, woman is re-tested. If continues to remain non-reactive, will schedule an OCT.
Contraction Stress Test CSTOxytocin Challenge Test OCT • A means of identifying the fetus that is at risk for intrauterine asphyxia. • Usually shows if there is placental insufficiency.
Procedure for an OCT • Oxytocin (Pitocin) stimulation started IV • Electronic fetal monitor attached • Goal -- have 3 contractions in 10 minutes • Results: • Negative -- 3 contractions in 10 minutes with NO signs of late decelerations • Positive -- repetitive persistent late decelerations occurring with more than half the contractions
Oxytocin Challenge Test Example of a positive contraction stress test (CST). Repetitive late decelerations occur with each contraction. Note that there are no accelerations of FHR with three fetal movements (FM). The baseline FHR is 120 beats per minute. Uterine contractions (bottom half of the strip) occurred four times in 12 minutes.
Biophysical Profile Comprehensive assessment of five Biophysical variables: • Fetal breathing movement • Fetal movements of body or limbs • Fetal tone (extension and flexion of extremities) • Amniotic fluid volume – visualized as pockets around the fetus • Reactive FHR with activitity (reactive NST)
Biophysical Profile By combining these five assessments, the BPP helps to identify the compromised fetus and to confirm the healthy fetus Since it combines several assessments, it is a better indicator of fetal well-being
Biophysical Profile • A score of 2 is assigned to each normal finding for a maximum score of 10. • Scores of 8-10 are considered normal • Lower scores are associated with a compromised fetus and warrant further assessment and possible delivery of the baby.
Kick Counts • The mother should assess fetal movements called “kick counts” each day. • Fetal movement is associated with the condition of the fetus.