Chapter 3 Antenatal Assessment and High-Risk Delivery (also equipment)

Chapter 3Chapter 3

Antenatal Assessment and Antenatal Assessment and

High-Risk Delivery High-Risk Delivery

(also equipment)(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 insufficiencyToxic 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 arteryAbout 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 abnormalitiesUmbilical 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. Anti-hepatitis 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 deliveryPosition 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 non-medically 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

VACUUM

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.

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)

EquipmentDuring 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 placement1.Size: 5 Fr umbilical catheter2. Vein: larger but floppy wall3. 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 calculation6. Connect the catheter to the fluid and tubing7. Obtain an X-ray film8. Desired position : catheter tip 0.5~1.0cm above the diaphragm9. 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.

Baby Weight(kg)

Tube Size(mm)

Oral Tube Length at Lip

(cm)

Nasal Tube Length at

Nose(cm)

Suction Tube Size(Fr)

<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