Transcript Fetal Distress

Fetal Distress
Song weiwei
[email protected]
Cell phone:13591441088
What is fetal distress?
• Fetal distress is the term commonly used to
describe fetal hypoxia. It is a clinical diagnosis
made by indirect methods and should be defined
as:Hypoxia that may result in fetal damage or
death if not reversed or the fetus delivered
immediately.
• More commonly a fetal scalp pH of less than 7.2
is used to indicate distress
Etiology
• Fetal oxygen supplied from:
– maternal circulation-----placenta------umbilical
cord------fetus
• maternal factors
– cardiovescular diseases
– acute bleeding
– uterus
Etiology
• Fetal factors
– cardiovescular dysfunction
– deformity
• umbilical cord and placental factors
– abnormal cord:entanglement,
nuchal umbilical cord
prolapse of cord
– abnormal placenta
Causes of Hypoxia*
risk factors
Maternal risk factors
• Diabetes
• Pregnancy-induced or chronic hypertension
• Maternal infection
• Sickle cell anemia
• Chronic substance abuse
• Asthma
• Seizure disorders
• Post-term or multiple-gestation pregnancy
Intrapartum causes of fetal
hypoxia**
• Abnormal presentation of the fetus (i.e.
breech)
• Premature onset of labor
• Rupture of membrane more than 24 hours
prior to delivery
• Prolonged labor
• Administration of narcotics and anesthetics
• Maternal hypoventilation
• Maternal hypoxia
• Hypotension can be caused by either
epidural anaesthesia or the supine position,
which reduces inferior vena cava return of
blood to the heart. The decreased blood
flow in hypotension can be a cause of fetal
distress (supine hypotension syndrome**).
Pathophysiology
• Hypoxia!
– Acidosis----sympathetic nerve excited---• hypertension,
• tachycardia (initial signs)
– profound acidosis-----vagus nerve---• hypotension,
• bradycardia,
• hyperperistalsis----meconium discharge
– chronic condition:
• nutritional deficiency----FGR
Clinical manifestation
• Chronic fetal distress
–
–
–
–
–
FGR
dysfunction of maternal-placental-fetal unit
fetal heart monitoring
fetal movement calculation
amnioscopy
Clinical manifestation
• Acute fetal distress
–
–
–
–
fetal heart rate
characteristics of fluid
fetal movement
acidosis
How to define the newborn
asphyxia
• Usually with fetal distress.
• Apgar score: 8-10 normal
•
4-7 mild asphyxia
•
0-3 severe asphyxia
Effects of Asphyxia
• Fetal hypoxia is associated with severe
complications in all systems. The infant
may suffer:
• Hypoxic ischemic encephalopathy
• Meconium aspiration syndrome
• Acidosis with decompensation
• Cerebral palsy
• Neonatal seizures
Mecunium
• Normal condition: mature of colon
• Fetal hypoxia can stimulate fetal colonic
contraction that leads to evacuation of meconium
(fetal stool) into the amniotic fluid
• How meconium is dealt with will depend on what
it looks like and what your provider's approach is.
Old meconium is yellow and less likely to be a
problem .
Meconium
• Thick, green, particulate meconium which may have
already caused baby to "gasp" in utero.
• If the meconium is accompanied by decreased heart rates
that do not recover well, a c-section will be the safest
approach.
• Fetal gasping due to the lack of oxygen which then causes
aspiration of the meconium into the lungs.
• The presence of this material can produce bronchial
obstruction and a chemical pneumonitis and treatment
must be initiated during delivery. If not adequately
removed, the meconium blocking the airways can lead to
further hypoxia.
•
Meconium aspiration most often
occurs in
•
•
•
•
•
Term infants
Growth-retarded infants
Post-term infants
Breech presentation delivery
The degree of meconium aspiration and the length of
exposure to meconium determines the severity of the
hypoxia suffered by the fetus. Staining of the umbilical
cord, skin, or nails of the infant indicates exposure to
meconium 3 to 6 hours in utero prior to delivery.
Assessment
**
Antepartum Testing:
Tests for antepartum fetal evaluation include:
• Fetal movement count
• Non stress test
• Contraction stress test
• Biophysical profile
Fetal movement
• Fetal movement counts are performed by the
mother and are an inexpensive, noninvasive
method of assessing fetal well-being. The patient
records the number of times she feels fetal
movement within a designated time period. The
exact number of normal perceived movements has
not been determined, however approximately 10
movements should be felt within a 12 hour period.
Non Stress Test (NST)
• The is an indirect measurement of
uteroplacental function and
requires specialized equipment and
trained personnel.
• This test measures the detection of
heart rate accelerations associated
with perceived fetal movements.
• A reactive or normal stress test
will exhibit at least two
accelerations in the fetal heart rate
in a 20-minute period.
Contraction Stress Test (CST)
• CST or oxytocin challenge test, is more
costly and presents more of a risk to the
fetus. but identifies fetal reserve during
contractions. The test measures late
decelerations during contractions induced
by either nipple stimulation or oxytocin
infusion. The test is negative if no late
decelerations are observed.
Biophysical profile
•
•
•
•
•
fetal movement
amniotic fluid volume
respiratory movement
movement of extremity
NST
Intrapartum Testing
Tests utilized to assess fetal well being during
labor include:
• Intermittent auscultation of the fetal heart
rate
• Continuous electronic fetal monitoring
• Scalp pH measurement
• Measurement of the fetal heart rate: abnormal
decelerations and decreased variability during
contractions are suggestive of fetal distress.
• Intermittent auscultation of the fetal heart rate is a
reliable indicator of fetal well being and can be
used in low risk deliveries. Routine electronic
fetal monitoring is not recommended for low-risk
women in labor when adequate clinical monitoring
including intermittent auscultation by trained staff
is available .
• Continuous intrapartum fetal monitoring is
the mainstay in most modern obstetric units.
The heart rate of the fetus is monitored to
detect increases or decreases during
contractions. The variability and trends are
interpreted to determine fetal distress or
well being.
• Scalp pH measurement helps to determine
the presence of acidosis and fetal hypoxia
and may influence the decision of
whether to continue observation or to
perform a cesarean delivery. Neurologic
deficits usually occur when there is a
severe acidosis, due to hypoxia, present at
birth. Severe hypoxia will often cause
hypoxic-ischemic encephalopathy in the
infant.
What’s the typical signs of fetal
distress?**
Typical signs of fetal distress include :
• late heart rate decelerations
• variable decelerations
• prolonged bradycardia
• indications of meconium staining.
• Intrapartum hypoxia is thought to be the
leading cause of cerebral palsy and now
accounts for 3 to 15% of cerebral palsy
cases. Chronic fetal hypoxia, caused by
maternal smoking or anemia, may also
contribute to a predisposition for Sudden
Infant Death Syndrome (SIDS).
Treatment of Hypoxia
Mother’s condition must be treated to prevent
hypoxia to the fetus including:
• Blood pressure stabilization
• Maternal positioning on the left side
• Monitoring maternal oxygenation
• Pelvic exam to identify cord presentation
Treatment of Hypoxia
• Oxygen administration to the mother may provide
additional availability of oxygen to the fetus.
Trained neonatal resuscitation staff should be
available at all times and should be present in the
delivery suite for those patients with known risk
for fetal distress or hypoxia.
• Cesarean sections are performed if all else fails,
and are the last alternative when faced with the
possibility of fetal distress.
The decision to delivery interval
• Medical litigation is on the rise in our
country particularly with relation to
obstetrics. The day is not far when
premiums for malpractice nsurance rise
parallel to the rise in the compensation
offered for these cases. Majority of the
cases seem to be due to the delay in the
decision to delivery interval rather than the
problems with diagnosis.
The decision to delivery interval
• Although there is poor correlation between FHR
patterns and long term outcome a significant
association has been noted between the decision to
delivery interval and admission to the neonatal
intensive care unit for neonatal asphyxia
• An effort must be made to reduce the decision to
delivery interval and restrict it to not more than 30
minutes. It should be the norm to keep the women
and her relatives apprised of the situation of the
labor at all times and involve them in the decision
making.
The decision to delivery interval
• In some cases of fetal distress immediate operative
delivery may be the only option to ensure a
healthy neonate. Even in these situations
intrauterine resuscitation can play a role in
enhancing the perinatal outcome. Ultimately,
efficient management and a good outcome in cases
of fetal distress reflects a strong infrastructure and
good coordination between the obstetrician, the
nursing staff, the staff in the operation room and
the neonatologist.
Premature rupture of membrane
(PROM)
What is premature rupture of
membranes?**
• The diagnosis of PROM is made whenever the bag
of water ruptures before the onset of true labor.
• PPROM: Preterm premature rupture of
membranes is the rupture of membranes during
pregnancy before 37 weeks' gestation.
It occurs in 3 percent of pregnancies and is the
cause of approximately one third of preterm
deliveries.
Incidence
• Varied greatly 2.7%--17%
• PROM is causally related to about 10%
perinatal deaths regardless of gestation age.
Its occurrence before term adds the risk of
neonatal respiratory distress syndrome
(NRDS) from hyaline membrane disease to
the risk of chorioamnionitis , neonatal
sepsis associated with ascending infection.
What causes premature rupture of
membranes?**
• The exact etiology of PROM remains
unknown, there have been many postulated
causes, but a single common denominator
has not yet been found.
What causes premature rupture of
membranes?**
• Infection: subclinical infection, chorioamnionitis
• coitus : patients who had coitus within 7 days before
delivery.
• low socioeconomic conditions : less likely to receive
proper prenatal care)
• sexually transmitted infections such as chlamydia and
gonorrhea
What causes premature rupture of
membranes?**
•
•
•
•
•
Previous preterm birth
Vaginal bleeding
Cigarette smoking during pregnancy
Trauma
Cervical incompetence/cervical lacerations
/cervical operations
• Polyhydramnios/multiple gestations
• Black patients are at increased risk of preterm
PROM compared with white patients.
What causes premature rupture of
membranes?**
• unknown causes
• There appears to be no single etiology of
preterm PROM. It is likely that multiple
factors predispose certain patients to
preterm PROM.
Complications of Preterm PROM
Complications
Incidence (%)
Delivery within one week
50 to 75
Respiratory distress syndrome 35
Cord compression
32 to 76
Chorioamnionitis
13 to 60
Abruptio placentae
4 to 12
Antepartum fetal death
1 to 2
What are the symptoms of PROM?
• The following are the most common
symptoms of PROM. However, each
woman may experience symptoms
differently. Symptoms may include:
• leaking or a gush of watery fluid from the
vagina
• constant wetness in panties
How is premature rupture of
membranes diagnosed?*
• In addition to a complete medical history and physical
examination, PROM may be diagnosed in several ways,
including the following:
• an examination of the cervix (may show fluid leaking from
the cervical opening)
• testing of the pH (acid or alkaline) of the fluid
accuracy rate:93-96%
False-positive:
cervicitis/vaginitis/presence of semen ,alkaline
urine/blood in vagina
• looking at the dried fluid under a microscope (may show a
characteristic fern-like pattern)
Management
• Hospitalization
• expectant management (in some cases of
PPROM, the membranes may seal over and
the fluid may stop leaking without
treatment)
• monitoring for signs of infection such as
fever, pain, increased fetal heart rate, and/or
laboratory tests
Management
• corticosteroids ：that may help mature the lungs
of the fetus (lung immaturity is a major problem
of premature babies). However, corticosteroids
may mask an infection in the uterus.
• antibiotics (to prevent or treat infections)
• tocolytics - medications used to stop preterm
labor.
• delivery (if PROM endangers the well-being of
the mother or fetus, then an early delivery may be
necessary to prevent further complications)