Chapter 14: Intrapartum Fetal Surveillance Flashcards
What are the purposes of intrapartum fetal assessments?
- Evaluate how the fetus tolerates labor
2. Identifies hypoxic insult to the fetus during labor
Adequate fetal oxygenation needs five related factors:
- Normal maternal blood flow and volume to the placenta
- Normal oxygen saturation in maternal blood
- Adequate exchange of oxygen and carbon dioxide in the placenta
- An open circulatory path between the placenta and the fetus through vessels in the umbilical cord.
- Normal fetal circulatory and oxygen-carrying functions.
How can uterine activity affect uteroplacental exchange?
- During labor, contractions gradually compress the spiral arteries, temporarily stopping maternal blood flow to the fetus.
- Fetus depends on the oxygen supply already present in body cells, erythrocytes and intervillous spaces. (Oxygen supply is enough for about 1-2 minutes)
What can affect uteroplacental exchange and fetal oxygenation?
- Uterine Activity
- Placental Disruptions
- Fetal Alterations
- Maternal Cardiopulmonary Alterations
- Interruptions in Umbilical Flow
How can placental disruptions affect uteroplacental exchange?
- Abruptio placenta (reduces the placental surface area available for exchange)
- Placenta previa (blood loss = decreased BF to fetus)
Abruptio Placenta
Premature separation of a normally implanted placenta
Placenta Previa
Abnormal implantation of the placenta in the lower uterus at or very near the cervical os.
Uterine Activity Assessment: External
Placements of monitor on top of the fundus to detect contractions.
What maternal cardiopulmonary alterations can affect fetal oxygenation?
- Aortocaval compression
- Maternal HTN
- Maternal acid-base alterations
- Hemorrhage
How does aortocaval compression affect fetal oxygenation?
- It occurs when a pregnant woman lies in supine position and the weight of the uterus compresses the aorta and the inferior vena cava.
- Thus, it reduces blood return to her heart, lowers her CO, and can reduce placental perfusion.
What can interrupt umbilical blood flow and oxygenation to the fetus?
- Compression by a unchallenged cord (one that is wrapped around the fetal neck) or by a not in the cord.
- Oligohydramnios (d/t inadequate amniotic fluid to cushion the cord)
- Inadequate Wharton’s Jelly
What are fetal alterations that can affect fetal oxygenation?
- Low circulation fetal blood volume
- Fetal hypotension
- Fetal anemia
Fetal Assessment
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Position and Presentation of the ..
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Leopold’s Maneuver
- Provide a systematic method for palpating the fetus through the abdominal wall during the later part of pregnancy.
- These maneuvers provide valuable information about the location and presentation of the fetus
What is a normal fetal heart rate?
110-160 bmp
Intermittent Electronic Fetal Monitoring
Done with a short strip taken at regular intervals during labor or during early labor
Continuous Electronic Fetal Monitoring
Starts shortly after the woman is admitted.
When should you use intermittent electronic fetal monitoring?
For high-risk patients such as DM
When should you use continuous electronic fetal monitoring?
When coming in for labor or when on any medications.
…….
Reactivity
If baby is nonreactive, baby is not getting enough perfusion.
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Fetal Scalp Electrode
Detects electric signals from the fetal heart.
Can become easily displaced.
What are causes of fetal tachycardia?
- Maternal fever
- Maternal dehydration
- Maternal or fetal hypoxia
- Fetal acidosis
- Maternal or fetal Hypovolemia
- Fetal cardiac dysrhythmias
- Maternal severe anemia
- Maternal Hyperthyroidism
- Drugs administered to mother
What are causes of fetal bradycardia?
- Tachysystole
- Maternal hypotension
- Fetal head compression
- Fetal hypoxia
- Fetal acidosis
- Fetal heart block
- Umbilical cord compression -> oligohydramnios
- abruptio placenta
- Late second-stage labor with maternal pushing
*anything that removes BF will drop HR
Tachysystole
When the contractions are so frequent and never return to baseline → no oxygen is getting to the fetus during the “relaxation periods” because the contractions have no relaxation periods.
Early Decelerations: Characteristics
- Requires no intervention.
- Has a gradual decrease from baseline.
- Mirrors contractions
- Consistent appearance