Chapter 7:

The High-Risk Infant

Infants at high-risk are those who are expected to need special medical procedures at delivery. Both maternal and infant conditions can put a newborn at risk, and some of the factors include but are not limited to those on the following list. At the end of the outline, you will find a more in-depth discussion of some risk factors.

Maternal issues that can put an infant at risk for a problem delivery include:

• Health: Obesity or overweight condition, diabetic, emotionally stressed, viral infection early in pregnancy, exposure to radiation

• Lifestyle issues: tobacco, drug or alcohol use

• Obstetrical issues and complications:

• Previous delivery problems (still borns, premies)
• First pregnancy late in life
• Multiple birth (twins, etc.)
• Post or prematurity
• Breech positioning
• Cesarean section
• Toxemia of pregnancy
• Abnormal or insufficient placenta
• Prolapsed cord
• Premature rupture of amniotic sac
• Meconium in amniotic fluid

At the time of delivery, the infant can present with conditions that signal high-risk condition, including:

• Less than 36 weeks of gestation 36 weeks

• Acute Respiratory Distress Syndrome (ARDS)

• Infection, blood diseases, or other anomalies

• The need for medications or special surgeries at delivery

It is crucial to assess fetal risk factors prior to birth. Approximately 29% of all pregnancies are deemed to be at risk for at least one of the complications listed above. In addition, approximately 5-10% of those at risk pregnancies require the administration of CPR, so be sure your CPR card is current.

Reviewing of maternal history is an obvious way to identify potentially high-risk neonates. A red flag should go up if you find evidence of a history of heart or lung disease, use of controlled substances, cigarette smoking, or infections. Low socioeconomic status or lack of education can also be red flags because they are often related to inadequate prenatal care.

Expectant mothers >17 years of age or <38 should be seen as potentially being at risk, and the history of both current and all previous pregnancies should be reviewed for risk factors no matter the age of the soon-to-be mother. When reviewing clinical records, remember that the term gravida refers to pregnancy. Para refers to a pregnancy that terminated with the delivery of a viable neonate. Primipara refers to the mother's first delivery. Multiparous refers to a woman who has had two or more pregnancies which resulted in viable fetuses.

A mother's prior pregnancies involving problems should be considered carefully because history has a strong tendency to repeat itself in matters relating to childbirth. A history of fetal asphyxia, prematurity, RDS, maternal toxemia, ruptured membranes, infections, or bleeding during the current pregnancy are all reasons to consider the current fetus as being at risk for complications.

Multiple gestation can lead to problems, including: a breech birth, placental and cord problems, intrauterine growth retardation, and increased chance for premature death. Mortality even increases with twins, particularly identical twins. Twin transfusion syndrome, where the circulations are connected, is also possible. This causes one baby to be polycythernic and the other to be anemic. The polycythernic baby manifests congestive heart failure and increased bilirubin levels. The anemic baby manifests hypotensive symptoms.

The presence of maternal diabetes mellitis (DM) is another cause for concern because problems commonly associated with DM include:

• prematurity
• congenital anomalies
• a predisposition to toxemia
• birth injury due to large baby
• still birth

Less severe DM is associated with delayed maturation of the lung, while severe DM causes chronic intrauterine stress and can accelerate lung maturation. Infants of diabetic mothers are more susceptible to infection, and more likely to be hypoglycemic, hypocalcemic, or have hyperbilirubinemia.

Toxemia involves the spread of bacterial toxins by the bloodstream and is a condition resulting from metabolic disturbances, such as pregnancy. The resultant maternal hypertension can have serious consequences and lead to eclampsia (convulsions and/or coma). The term pre-eclampsia, which is often used interchangeably with toxemia, means a toxemia of late pregnancy which is characterized by hypertension, edema and proteinuria.

Toxemia during pregnancy causes a decrease in placental blood flow leading to uteroplacental insufficiency (UPI). UPI may occur in post maturity infants, cyanotic maternal heart disease, or chronic hypoxia from maternal pulmonary disease.

UPI is more likely in the elderly primigravida, and can result in: intrauterine growth retardation, fetal death, chronic asphyxia, or the passage of meconium. When UPI is suspected, it can be assessed by measuring maternal urinary estriol levels. Urinary estriol normally increases throughout pregnancy, but measurements showing low or falling levels are indicative of UPI.

The placenta normally implants in the upper wall of the uterine cavity, but when an implantation takes place in the lower portion of the uterus, it is called placenta previa, or if the placenta separates prematurely from the uteral wall (abruptio placentae), the fetus is placed at risk. There are three types of placenta previa:

• A low implantation occupies the lower portion of the uterous, but does not cover the cervical opening.
• A partial placenta previa, covers a portion of the cervical opening, but does not cover it completely.
• In total placenta previa, the placenta is implanted low and completely covers the cervical opening.

All types of placenta previa can be readily diagnosed by ultrasound, and all cause varying degrees of obstruction to fetal passage and increase the chance of premature labor, early separation of the placenta, and hemorrhage. The most serious of these complications involves the early separation of the placenta from the uterus, referred to as abruptio placentae.

Separation of the placenta frequently causes premature labor, complete with its attendant risks, to begin. Fetal mortality approaches 50% due to the acuteness of blood loss, and maternal mortality ranges from 2 to 10% in severe cases ending in fetal death. The most common cause of abruption is maternal hypertension of any origin, including preeclampsia. Treatment of abruptio placentae includes strict management of blood volume, maintaining a hematocrit of 30 vol%. This is accomplished by IV administration of blood or crystalloid solutions.

Premature rupture of membranes (ruptures occurring 24 or more hours prior to delivery) put premature neonates at risk because of the increased potential for infection. Infants are considered postmature after the 42nd week of gestation, at which time the placenta begins to deteriorate. These babies often appear small for their gestational age and show signs of dwindling away. Postmaturity also predisposes to increased morbidity, including intrauterine asphyxia, meconium passage, difficult labor, and even premature death.

The delivery circumstances can also be predictive of potential problems. Vaginal delivery literally squeezes much of the fluid out of the neonate's lungs, easing the transition to life outside the mother's womb. On the other hand, cesarean-section deliveries don't allow for the squeezing action, increasing the chances that neonate will need special treatment to clear fluid out of the lung and airway.

The neonate's amniotic fluid should be examined at birth for odor, color, consistency, and the presence of meconium. Normal amniotic fluid is thin, pale, and watery. Thick or foul smelling fluid may be indicative of infection. Yellow fluid can be related to infection or hypoxia. If part of the placenta is not perfused, the amniotic fluid may have a red wine color.

Meconium, a dark greenish stool, passes into the amniotic fluid in about 3-5% of preterm births, 10% in term babies, and about 40% of the time in post-term fetuses of more than 42 weeks gestation. The presence of thick particulate meconium in the amniotic fluid requires that as soon the head is delivered, the mouth, oro- and laryngopharynx be thoroughly suctioned to remove any meconium present. Upon delivery of the distressed neonate, the trachea should immediately intubated, suction applied to the end of the endotracheal tube, and the tube withdrawn.

Suction pressure should be set at 100 mm Hg, and suction applied for no more than 3-5 seconds. If meconium is suctioned out of the trachea, the neonate should be reintubated with a new endotracheal tube and the procedure repeated until no meconium is suctioned. Blowby oxygen can then be delivered to help alleviate hypoxia with PPV beginning after completion of suctioning.

Each hospital needs to have a protocol covering the problem created when a severely depressed newborn has also aspirated meconium. Which risk is greater: that of blowing meconium further into the lungs with PPV before the trachea is clear, or risking asphyxia by not providing PPV until the trachea is clear? The general consensus on the issue seems to be that in severely depressed newborns, it may not be possible to clear the trachea of all meconium before initiating PPV. Be sure you know your hospital's policy on this clinical dilemma.

The average fetal heart rate (FHR) in early gestation is 140 beats per minute, dropping to an average of 120/min near term. FHR should be monitored continuously during labor, with normal ranging from 120 to 160/min. Fetal cardiac status can be measured either by simple ausculation with a stethoscope, or with relatively easy-to-use sophisticated electronics. Either way, routine monitoring of fetal heart rates has so significantly diminished adverse results of delivery that nearly every labor room now has a fetal heart monitor.

There is a normal beat-to-beat variation in the FHR, and an intact neural system responds to stimuli by increasing or decreasing FHR. For example, in a normal fetus, a loud noise causes a transient increase in FHR. If there is no FHR response to stimuli, higher brain-functions may not exist, and a total lack of variation may indicate brain stem activity only.

FHR monitoring can identify fetal distress (see Table 2) that is difficult to diagnose otherwise, and because the FHR monitor shows heart responses to asphyxia, it is an excellent way to identify infants who are being asphyxiated in utero. Since FHR also should correlate with contractions (normally, there is an increase of 15-20 beats in FHR with each contraction), FHR is usually monitored along with uterine contractions so the correlation between can be observed.