Chapter 3
Antenatal Assessment and
High-Risk Delivery
(also equipment)
Introduction
• During gestation period, the fetus undergoes various
physiological development which requires medical
attention to prevent complications at birth.
• Cooperation among all members of the health care team
is essential in identifying signs and symptoms of problems
that might occur during pregnancy and thus find early
solutions
• Maternal history, antenatal assessment and intrapartum
monitoring are all important in identifying early sign of
risk in fetal development before perinatal period.
Maternal History and Risk Factors
Preterm delivery
• Before 37 weeks of gestation
Cervical insufficiency
Toxic habits of pregnancy
• Smoking
• Illegal drugs
• Alcohol
Maternal History
• As a RT, you should review thoroughly the chart and assess the
following:
•
•
•
•
Hx of prenatal care, age of mother, is multiple gestation present
Para/Gravida
Current medications the mother is on
Approximate Gestational Age, note if water has broken, if birth is
imminent, will it be a C-section or vaginal birth
• Cervical insufficiency (Includes shortening or funneling due to
weight of the uterus and developing fetus pushing down)
• PROM (Premature rupture of fetal membrane...with hx of
premature birth, risk of another premature birth goes up)
• Toxic habits in pregnancy: Alcohol, Smoking, Cocaine...all potent
teratogens
Maternal History
• As a RT, you should review thoroughly the chart and assess the
following:
• Presence of Preclampsia (A triad of hypertension, proteinura and
generalized edema), Severe Preclampsia (160/110.mmHg,
>5g/24hrs of protein, pulmonary edema, fetal growth restriction,
oliguria, thrombocytopenia, headache, epigastric or RUQ pain,
hepatocellular dysfunction, seizure)
• Eclampsia, Placenta Previa, abruption
• Genetic and cardiac abnormalities
• Maternal HTN (2nd leading cause of maternal mortality, after
embolism. Infant at risk for growth restriction, placental
abruption and preterm delivery)
CERVICAL INSUFFICIENCY
• Patients with risk factors for cervical insufficiency are
recommended for evaluation by ultrasound examination
of the cervix starting at 16wks of gestation.
• Cervical insufficiency is where the cervix dilate
prematurely before the fetus develops fully.
• Interventions such as cervical cerclage where sutures are
placed around the cervical canal have been used in
detection of such abnormality.
• An elective cerclage should be considered for patients
with history of 3 or more unexplained mid-trimester
pregnancy losses or preterm delivery.
Maternal History and Risk Factors (cont.)
Hypertension
• Preeclampsia
Diabetes mellitus
• Pregestational diabetes
• Gestational diabetes
Infectious disease
• Group B Streptococcus
Preclampsia
• We may be familiar with pre-eclampsia, preeclampsia or
often also called toxemia is a condition that can be
experienced by any pregnant woman.
• The disease is characterized by increased blood pressure
which was followed by increased levels of protein in the
urine. Pregnant women with preeclampsia also
experience swelling in the feet and hands.
• Preeclampsia generally appear in mid-gestation,
although in some cases there were found in early
pregnancy.
• http://www.youtube.com/watch?v=2t4BKI6NtTk
Eclampsia
• Eclampsia is a condition of continuation of
preeclampsia are not resolved properly.
• In addition to experiencing symptoms of
preeclampsia, in women affected by eclampsia
are also often suffer from seizures
• Eclampsia can cause coma or even death of
either before, during or after childbirth.
http://www.youtube.com/watch?v=97j0lJXMTlQ
Gestational Diabetes Mellitus GDM
• Intrauterine growth restriction, preterm delivery
and placental abruption has been found to cause
an increase in perinatal morbidity and mortality.
• Hypertensive disease states complicates 12-20%
of pregnancies in the US and second only to
embolism.
• GDM caused by abnormal glucose tolerance that
occurs during pregnancy. Mom has increased risk
of getting type II diabetes after pregnancy.
Increased risk of macrosomia (large baby 4000g),
Traumatic vaginal delivery, and possible fetal
death(small risk)
Group B Streptococcus
• type of bacterial infection that can be found in a pregnant
woman’s vagina or rectum. This bacteria is normally found in
the vagina and/or rectum of about 25 % of all healthy, adult
women.
• Those women who test positive for GBS are said to be
colonized. A mother can pass GBS to her baby during delivery.
GBS is responsible for affecting about 1 in every 2,000 babies
in the United States. Not every baby who is born to a mother
who tests positive for GBS will become ill.
• Although GBS is rare in pregnant women, the outcome can be
severe, and therefore physicians include testing as a routine
part of prenatal care.
Group B Streptococcus
• The CDC has recommended routine screening for vaginal strep
B for all pregnant women.
• Performed between the 35th and 37th week of pregnancy
(studies show that testing done within 5 weeks of delivery is
the most accurate at predicting the GBS status at time of
birth.)
• The test involves a swab of both the vagina and the rectum.
The sample is then taken to a lab where a culture is analyzed
for any presence of GBS. Test results are usually available
within 24 to 48 hours.
• The American Academy of Pediatrics recommends that all
women who have risk factors PRIOR to being screened for GBS
(for example, women who have preterm labor beginning prior
to 37 completed weeks’ gestation) are treated with IV
antibiotics until their GBS status is established.
TOXIC HABITS IN PREGNANCY
• Maternal habits should be assessed during early stages
of gestation. Smoking, alcohol use and other illicit drugs
use during pregnancy can have adverse effects on fetal
development.
• Alcohol is a potent teratogen, an agent or factor that
causes malformation of the fetus. Alcohol abuse during
pregnancy has been associated with mental retardation
and prenatal and postnatal growth restriction. Brain,
cardiac, spinal and craniofacial anomalies have also been
associated with the abuse of alcohol during pregnancy.
No safe range for drinking alcohol during pregnancy has
been established.
TOXIC HABITS IN PREGNANCY
• Smoking during gestation period equally has adverse effect on
fetal development. Carbon monoxide and nicotine produce
during smoking, reduces the amount of oxygen delivered to
the fetus and the placenta during pregnancy. A strong
correlation exist between small birth weight and cigarette
smoking with mean weight of 200g or less recorded infants as
compared to infants of non-smokers
• Cocaine has strong sympathomimetic effects which causes
vasoconstriction. It can cause various maternal complications
such as myocardial infarction, stroke, seizures, bowel
ischemia, and death if used during gestation period. Cocaine
usage has also bee associated with placental abruption,
preterm delivery and growth restriction. It also causes
congenital malformation of the limbs, heart, brain and
genitourinary tract. Children born to women who abuse
opiates during pregnancy tend to have significant withdrawal
symptoms after birth.
Maternal History and Risk Factors (cont.)
Fetal membranes
• Premature rupture of membranes
Umbilical cord abnormalities
• Number of vessels
• Length of cord
Placenta
• Placenta abruptio
• Placenta previa
Fetal membranes
• PROM
• Risk factors for PROM can be a bacterial infection, smoking, or
anatomic defect in the structure of the amniotic sac, uterus,
or cervix. In some cases, the rupture can spontaneously heal,
but in most cases of PROM, labor begins within 48 hours.
When PROM occurs, it is necessary that the mother receives
treatment to avoid possible infection in the newborn
• Maternal risk factors for a premature rupture of membranes
include chorioamnionitis or sepsis. Association has been found
between emotional states of fear
• Fetal factors include prematurity, infection, cord prolapse,
malpresentation or genetic mutations
Umbilical cord abnormalities
• The cord contains three blood vessels: two arteries and one
vein.
• The vein carries oxygen and nutrients from the placenta
(which connects to the mother's blood supply) to the baby.
• The two arteries transport waste from the baby to the
placenta (where waste is transferred to the mother's blood
and disposed of by her kidneys).
• A gelatin-like tissue called Wharton's jelly cushions and
protects these blood vessels.
• A number of abnormalities can affect the umbilical cord. The
cord may be too long or too short. It may connect improperly
to the placenta or become knotted or compressed
Umbilical cord abnormalities
• They usually are not discovered until after
delivery when the cord is examined directly.
• Single umbilical artery
About 1 percent of singleton and about 5
percent of multiple pregnancies (twins, triplets
or more) have an umbilical cord that contains
only two blood vessels, instead of the normal
three. In these cases, one artery is missing (2).
The cause of this abnormality, called single
umbilical artery, is unknown.
Umbilical cord abnormalities
• Single umbilical artery have an increased risk for birth
defects, including heart, central nervous system and
urinary-tract defects and chromosomal abnormalities
• A woman whose baby is diagnosed with single umbilical
artery during a routine ultrasound may be offered certain
prenatal tests to diagnose or rule out birth defects
• These tests may include a detailed ultrasound,
amniocentesis (to check for chromosomal abnormalities)
and in some cases, echocardiography (a special type of
ultrasound to evaluate the fetal heart). The provider also
may recommend that the baby have an ultrasound after
birth.
Umbilical cord abnormalities
Umbilical cord prolapse occurs when the cord slips
into the vagina after the membranes (bag of waters)
have ruptured, before the baby descends into the
birth canal. This complication affects about 1 in 300
births
The baby can put pressure on the cord as he passes
through the cervix and vagina during labor and
delivery. Pressure on the cord reduces or cuts off
blood flow from the placenta to the baby, decreasing
the baby's oxygen supply. Umbilical cord prolapse can
result in stillbirth unless the baby is delivered
promptly, usually by cesarean section
Umbilical cord abnormalities
Vasa previa occurs when one or more blood vessels from
the umbilical cord or placenta cross the cervix underneath
the baby. The blood vessels, unprotected by the Wharton's
jelly in the umbilical cord or the tissue in the placenta,
sometimes tear when the cervix dilates or the membranes
rupture. This can result in life-threatening bleeding in the
baby.
Even if the blood vessels do not tear, the baby may suffer
from lack of oxygen due to pressure on the blood vessels.
Vasa previa occurs in 1 in 2,500 births
Umbilical cord abnormalities
• About 25 percent of babies are born with a nuchal cord
(the umbilical cord wrapped around the baby's neck)
• A nuchal cord, also called nuchal loops, rarely causes any
problems. Babies with a nuchal cord are generally
healthy.
• Sometimes fetal monitoring shows heart rate
abnormalities during labor and delivery in babies with a
nuchal cord. This may reflect pressure on the cord.
However, the pressure is rarely serious enough to cause
death or any lasting problems, although occasionally a
cesarean delivery may be needed.
• Less frequently, the umbilical cord becomes wrapped
around other parts of the baby's body, such as a foot or
hand. Generally, this doesn't harm the baby.
HERPES SIMPLEX VIRUS
Babies born to women with primary or recurrent
HSV outbreak during pregnancy, are at a risk of
getting infested with HSV during membranes
rupture or onset of labor.
The virus can ascend to infect the fetus and thus
cesarean delivery is undertaken as soon as possible
after membrane rupture or after the onset of labor.
HEPATITIS B VIRUS AND HUMAN IMMUNODEFICIENCY
VIRUS
• Both virus can cause death in the fetus therefore pregnant women should be
screened for HBV and HIV.
• The frequency of HIV infection is about 1 per 1000 in the obstetric population in
the United States with the prevalence high as 1-1.5% in inner-city populations.
30% of exposed fetuses will also acquire the infection. An antiretroviral drug,
zidovidne used during pregnancy, labor and as a chemoprophylaxis for 6wks in
exposed newborns is associated with a decrease in perinatal HIV transmission to
8.3%. Nursing should be discouraged in HIV positive women since the virus can
be transferred in the breast milk.
• Infants born to pregnanant women with HBV become infected at delivery. Antihepatitis B immunoglobulin treatments and vaccination within the first 12hrs of
life has helped in preventing 95% of neonatal infections. Cesarean delivery of
these newborns has no advantage.
• Cytomegalovirus, rubella, Toxoplasma, Listeria, mycobacteria and Treponema
pallidum (syphilis) can all affect the mother, fetus and fetoplacenta unit
significantly. Early diagnosis and treatments can help in avoiding complications.
Maternal History and Risk Factors (cont.)
Amniotic fluid
• Oligohydramnios
• Polyhydramnios
Mode of delivery
Position of the fetus
• Breech
Cesarean Section
C-section
• The first modern Caesarean section was performed by
German gynecologist Ferdinand Adolf Kehrer in 1881.
• A Caesarean section is usually performed when a vaginal
delivery would put the baby's or mother's life or health at risk,
although in recent times it has also been performed upon
request for childbirths that could otherwise have been natural.
• In 2007, in the United States, the Caesarean section rate was
31.8%.
• Medical professional policy makers find that elective cesarean
can be harmful to the fetus and neonate without benefit to
the mother, and have established strict guidelines for nonmedically indicated cesarean before 39 weeks.
C-Section indications
• Complications of labor and factors impeding vaginal delivery, such
as:
• prolonged labor or a failure to progress (dystocia)
• fetal distress
• cord prolapse
• uterine rupture
• hypertension in the mother or baby after amniotic rupture
• tachycardia in the mother or baby after amniotic rupture
• placental problems (placenta previa, placental abruption or placenta
accreta)
• abnormal presentation (breech or transverse positions)
• failed labor induction
• failed instrumental delivery (by forceps or ventouse (Sometimes a
trial of forceps/ventouse delivery is attempted, and if unsuccessful,
it will be switched to a Caesarean section.)
• large baby weighing >4000g (macrosomia); large mother
• umbilical cord abnormalities (vasa previa, multilobate including
bilobate and succenturiate-lobed placentas, velamentous insertion)
C-Section indications
• Other complications of pregnancy, pre-existing conditions and
concomitant disease, such as:
• pre-eclampsia
• hypertension
• multiple births
• previous (high risk) fetus
• HIV infection of the mother
• Sexually transmitted infections, such as genital herpes (which can be
passed on to the baby if the baby is born vaginally, but can usually be
treated in with medication and do not require a Caesarean section)
• previous transverse Caesarean section
• previous uterine rupture
• prior problems with the healing of the perineum (from previous
childbirth or Crohn's disease)
• Bicornuate uterus
• Rare cases of posthumous birth after the death of the mother
• Lack of obstetric skill - obstetricians not being skilled in performing
breech births, multiple births, etc. (In most situations, women can birth
vaginally under these circumstances. However, obstetricians are not
always trained in proper procedures)
C-Section risks to baby
• Non-medically indicated (elective) childbirth before 39 weeks
gestation "carry significant risks for the baby with no known
benefit to the mother."
• TTN: Retention of fluid in the lungs can occur if not expelled
by the pressure of contractions during labor.
• Potential for early delivery and complications: Preterm
delivery is possible if due-date calculation is inaccurate. One
study found an increased risk of complications if a repeat
elective Caesarean section is performed even a few days
before the recommended 39 weeks.
BREECH PRESENTATION
This mode of delivery creates a greater potential for
complications during labor. Factors contributing to breech
presentation includes multiparity, previous breech delivery,
uterine anomalies, fetal anomalies, multiple gestation and
polyhydramnios.
The term Breech Trial Collaborative Group conducted a
multicenter randomized controlled trial of planned
cesarean versus planned vaginal delivery for breech
presentation at term. It concluded that planned cesarean
delivery is preferred because of less risk for perinatal
mortality or serious morbidity and no increase in serious
maternal complications.
http://www.youtube.com/watch?v=O6jddbdeFUo
ASSISTED VAGINAL DELIVERY
Obstetric forceps is an instrument used
to cradle and guide the fetal head while
applying traction to expedite delivery.
The vacuum extractor is a suction device
that holds the head tightly and allows
traction to be applied. Indications for
forceps or vacuum usage include s
maternal cardiac , pulmonary or
neurologic disease which contraindicate s
the pushing process; maternal
exhaustion in labor and nonreassuring
fetal status.
VACUUM
Obstetrician forceps
Antenatal Assessment
Antenatal Assessment (cont.)
• Amniocentesis
• Diagnostics
• Lung maturity
• Abnormalities
• Laboratory results
• Chromosomal
Nonstress and Contractal Stress Test
• Placental function
• Fetal heart rate
• Movement
• Nonstress test
• Contractions
• Stress test
Contractal Stress Test
Contractal Stress Test (cont.)
Contractal Stress Test (cont.)
Contractal Stress Test (cont.)
Biophysical Profile
Intrapartum Monitoring
• Fetal heart rate
• Scalp blood gas
• Cord blood gas
• Fetal pulse oximetry
High-Risk Conditions
• Preterm birth
• Earlier than 37 weeks
• Comorbidity
• Risk factors
• Tocolysis
• Maternal steroids
High Risk Conditions (cont.)
• Post term delivery
• Causes
• Associated maternal and fetal
conditions
• Meconium aspiration
• Placental insufficiency
• Inducing labor (Pitocin)
Equipment
During delivery (as discussed in NRP)
• Flow inflating bag or Neo-Puff (T-piece)
• Suction equipment (bulb, 5/6 F, 8F, 10F) set at -60-80 mmHg,
Meconium aspirator
• Intubation equipment: ETT 2.5-3.5, cloth tape, scissors, blades 00-1
(straight blades); skin prep swabs, End Tidal CO2 detector
• Pulse Ox probe
• Blender
• Temperature probe
• Cord clamp
• Capillary tube/lancet
• OG feeding tube 8F
• Warm blankets/Radient warmer
• Medication box with Epinephrine, NS, UAC/UVC kit
UVC placement
1.Size: 5 Fr umbilical catheter
2. Vein: larger but floppy wall
3. Grasp the end of the umbilical stump with the curved hemostat to
hold it upright and steady.
4. Open and dilate the vein with forcep .
5. Insert depth
(a) the length from the xyphoid to the umbilicus and add
0.5~1.0 cm.
(b) 2/3 of shoulder-umbilicus distance
(c) half of the UA line calculation
6. Connect the catheter to the fluid and tubing
7. Obtain an X-ray film
8. Desired position : catheter tip 0.5~1.0cm above the diaphragm
9. Avoid the catheter entering the hepatic vein which may cause portal
hypertension.
UVC placement
• 10. When to suspect catheter entering the hepatic vein:
If you meet resistance and cannot advance the catheter
to the desired distance.
(a) Try injecting flush as you advance the catheter
(b) Withdraw catheter 2-3 cm, and gently rotate and
reinsert in an attempt to get it through ductus venosus.
UVC
• Position
• An umbilical venous catheter generally passes directly
superiorly and remains relatively anterior in the abdomen. It
passes through the umbilicus, umbilical vein, left portal vein,
ductus venosus, middle or left hepatic vein, and into the
inferior vena cava.
• The tip should lie at the junction of the inferior vena cava with
the right atrium.
• Too long
• If the umbilical venous
catheter is advanced too far
along its intended course, the
tip may end up in a number of
locations:
• left atrium and beyond
(through a patent foramen
ovale or an atrial septal defect)
• pulmonary vein
• left ventricle etc...
• right atrium and beyond
• superior vena cava
• right ventricle etc...
Most babies <1250 grams (<32 weeks) will need a 2.5 mm ID
(internal diameter) ET tube. 1250 - 3000 grams (32-38 weeks)
a 3.0 ID tube and >3000 grams (>38weeks) a 3.5 ID tube.
Nasal Tube
Length at
Nose
(cm)
Suction Tube Size
(Fr)
Baby Weight
(kg)
Tube Size
(mm)
Oral Tube
Length at Lip
(cm)
<1.0
2.5
5.5
7.0
6
1.0
2.5-3.0
6.0
7.5
6
2.0
3.0
7.0
9.0
6
3.0
3.0
8.5
10.5
6
3.5
3.0-3.5
9.0
11.0
8
4.0
3.5
9.0
11.0
8
ETT Confirmation
• The ET should be passed so that the tip lies approximately
midway between the vocal cords and the carina. Tube position
can be confirmed by:
• ensuring the ET tube tip is no more than between 2.5 to
3.0cm beyond the vocal cords (to avoid intubation of the right
main bronchus)
• use of End Tidal CO2 detector
• observing symmetrical chest-wall motion
• hearing equal air entry on both sides of chest and not over
stomach (may be an unreliable sign in tiny infants)
• seeing moisture in the ET tube during exhalation
• improvement of clinical condition
• chest x-ray (ET tube tip is seen at the level of T2-T3)
Taping
NCPAP
•A: Neonatal High Flow cannula up
to 8L
•B. Air/Oxygen Blender
•C. Flowmeter for resuscitation bag
•D. HFNC
•E. Tubing
•F. Heater
•G. Water for concha