Download Antenatal Assessment/Changes at birth

RSPT 2353 – Neonatal/Pediatric Cardiopulmonary Care
Changes at Birth
Lecture Notes
Reference & Reading: Chapter 3
I. Terms that are heard in L&D:
a. Para/Gravida/Abortions
 Para (P) – Pregnancy
 Gravida (G) – Live births
 Abortions (A) – Either elective, or spontaneous
 Example: P3 G1 A1
b. Type of delivery
 Vaginal
 Cesarean section
 VBAC
c. Current situation with mom and/or baby
II. Maternal History
a. Risk Factors
 Incompetent cervix
 Toxic habits
 HTN
 Diabetes Mellitus
 Infectious Diseases – GBS, HSV, HBV
III. Problems from Labor and/or Delivery
a. Dystocia – prolonged difficult labor
b. The longer the labor the more problems may arise
c. Causes include:
 Uterine dysfunction
 Abnormal Presentation
 Excessive fetal size
 Hydrocephalus
 Abnormality in size or shape of birth canal
IV. Problems with the placenta, umbilical cord, & fetal membranes
a. Fetal membranes
 Premature Rupture of Membranes (PROM)
 No longer sterile;  risk of fetal infection
  fetal fluid sac
b. Placenta Previa – placenta implants in lower portion of the uterine
cavity
 Low
 Partial
 Total
c. Abruptio Placentae –
 A normally attached placenta separates prematurely from
uterine wall
 Most common cause is Preeclampsia or eclampsia (PIH)
 Many risks involve for both mother, fetus & at delivery
d. Umbilical Cord Problems
 Prolapsed cord – the umbilical cord presents in the cervix
into the birth canal before the baby
 Nuchal cord – the umbilical cord wraps around the baby’s
neck
(http://www.merckmedicus.com/pp/us/hcp/framemm.jsp?
pg=www.merck.com/mmhe/sec22/ch261/ch261c.html)
 Cord knot – also called a true knot; a knot is made in the
umbilical cord
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V. Problems with Amniotic fluid (AFI)
a. Fluid within Amnion
b. Dynamic – constantly being replenished & absorbed
c. After 24-26 weeks gestation fluid is swallowed and replenished with
fetal urine
d. POLYHYDRAMNIOS – too much amniotic fluid present
 CNS malformations
 Orogastric malformations
 Down syndrome
 CHD
 IDM
e. OLIGOHYDRAMNIOS – scant or decreased amount of fluid
 Defect in urinary system – usually renal dysplasia or urethral
stenosis
 Potter’s syndrome
 Implications include: lung Hypoplasia, asphyxia, and
significant skeletal deformities
 Presentation later in gestation – umbilical cord compression
VI. Mode of Delivery
a. Vaginal most common
b. Forceps/ vaccum extraction
c. C-section – there are several risks involved:
 Accidental cutting
 TTN
VII. Multiple Gestation – more than one fetus present
a. Higher incidence of premature labor
b. Fraternal twins – separate placentas
c. Identical twins – shared placenta
VIII. Antenatal Assessment
a. Ultrasound
b. Amniocentsis – Performed to run for a variety of tests
 Routinely done on mothers over 35
 Not common practice because of risks involved
 Tests that can be performed:
1. L/S ratio –
a. Determines lung maturity
b. compares amount of lecithin to sphingomyelin
in amniotic fluid
c. lungs considered mature when L/S ration
reaches 2:1
2. Shake test –
a. Amniotic fluid mixed with ethanol
b. 15 minutes later if there is a ring of bubble
present, there is enough protein – lungs are
mature
3. Alpha-fetoprotein
a. Alpa-fetoprotein peaks in 12th week and then
decreases
b. If there is a break in fetal skin AFP will be
present
c. High level usually indicates neural defect
d. Low level indicates Down Syndrome
c. Nonstress Test and Contraction stress test
 FHR is monitored with fetal movement (NST) or with
induced contractions (CST)
 Reactive NST - FHR  with movement or contraction
 CST
1. Negative – no late decals
2. Positive – late decals w/ each contraction
3. Suspicious – some late decals w/ some contractions
d. Biophysical Profile (Table 3-1)
 Determines fetal risk
 Tests: fetal breathing, fetal movement, fetal limb tone, NST,
amniotic fluid volume
e. Fetal Heart Rate Monitoring
 Important reading along with variability
 Good indicator of what is going on with fetus during labor
 Three ways to monitor:
1. External abdominal transducer
2. Electrodes on abdomen
3. Spiral electrode
 Uterine contractions are monitored with a
tocodynamometer
 Fetal Heart Patterns
1. Baseline
2. Variability – changes with CNS depression, fetal sleep,
narcotic or sedative use, etc.
3. Bradycardia - <100bpm or a maintained 20 bpm drop
from baseline
4. Tachycardia – consistenly above 180 bpm; usually
maternal fever
5. Accelerations – FHR exceeds 160 bpm for <2 minutes;
good sign
6. Decelerations – FHR drops below 120 bpm for <2
minutes
a. Early (Type I) drops during contraction – benign
b. Late (Type II) don’t follow contractions –
uretoplacental insufficiency during
contractions
c. Variable (Type III) independent of contractions
– secondary to umbilical cord compression
IX. High risk conditions
a. Premature labor – Prevention is better!
 Tocolysis – process of stopping labor
1. Pharmacological – β-sympathomimetic (terbutaline &
ritodine); anti-convulsant (magnesium sulfate)
 Identification of risks for premature labor
 Bedrest1. Light-duty
2. Bedrest (home or hospital)
3. Trendelenburg
b. Postterm Pregnancy
 Increased risk for:
1. Large size
2. Meconium aspiration
3. Obstetrical trauma
 Labor often induced
X. Adaptation to Extrauterine Life
a. The first breath – Three things that influence the initiation of the first
breath
 Chemoreceptors detect changes in PaO2 & PaCO2
stimulate the baby to breathe
 Thoracic recoil and baby leaves vaginal canal
 Abrupt change in environment
b. Change from fetal to adult circulation
 Changes in circulatory Pressures
1. Umbilical cord is clamped, forcing blood to lower
extremities, raising arterial blood pressure
2. Initial breathing causes ↓ pulmonary vascular
resistance (FRC & ↑PaO2)
 Closure of fetal shunts
1. With ↑ pressures in L heart foramen ovale closes
2. Ductus arteriosus closes with the absence of
prostaglandins (smooth muscle constricts)
3. Umbilical arteries & veins constrict & become
ligaments
4. Ductus venosus also constricts & becomes ligament