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Maternal Newborn Nursing

23.2 Estimation of Gestational Age of the Newborn and Newborn Behavioral Assessment

Maternal Newborn Nursing23.2 Estimation of Gestational Age of the Newborn and Newborn Behavioral Assessment

Learning Objectives

By the end of this section, you will be able to:

  • Identify ways to estimate the gestational age of a newborn according to physical and neurologic maturity by using the Ballard estimation of gestational age tool
  • Determine a newborn’s social adequacy and capabilities by utilizing the Brazelton Neonatal Behavioral Assessment Scale

Estimating gestational age as well as assessing newborn behavior is another aspect of the complete exam of a newborn. The Ballard Score (Ballard et al., 2014) and the Brazelton Neonatal Behavioral Assessment Scale are included only in the newborn period and are specific tools of the nurse caring for newborns. When handling and touching the newborn, it is important the nurse wear gloves until the newborn has received their first bath and all the amniotic fluid, vaginal secretions, and blood on the skin are removed.

Estimating Newborn Gestational Age by Maturity Rating: The Ballard Score

The nurse uses the Ballard maturity rating to establish the accuracy of the age of the newborn in the first 4 hours after birth. The two components of clinical gestational age assessment are external physical characteristics and neuromuscular maturity. Assessing gestational age can be especially important when the birth parent has had limited prenatal care and the gestational age is unknown or unclear. Neurologic examination is done to assess physiologic maturation in addition to physical development. However, the newborn’s nervous system is often unstable during the first 24 hours of life, and therefore their reflexes may be unstable. If their neurologic findings deviate from the gestational age derived by evaluation of external characteristics, it is recommended that a second evaluation be completed in 24 hours. The neurologic assessment, especially reflexes, are especially important in newborns at less than 34 weeks’ gestation. That is because neurologic changes are significant between 26 and 34 weeks’ gestation, while significant physical changes are less evident. It is also important that the nurse complete the assessment during quiet, calm times for the newborn so that their neurologic status can be assessed accurately.

Ballard et al. (1991) developed the estimation of gestational age by maturity rating, or Ballard Score, in which each physical and neuromuscular finding is assigned a point value. Those points are then totaled, and the total score is matched to a gestational age scale to determine the approximate gestational age of the newborn. The maximum score on the Ballard scale is 50, which correlates to a gestational age of 44 weeks. For example, on completing a gestational assessment of a one-hour-old newborn, the nurse gives a score of 2 to all the physical characteristics, for a total of 12, and gives a score of 3 to all the neuromuscular assessments for a score of 18. That would equal a score of 30, indicating a gestational age of 36 weeks’ gestation. Usually, the nurse will not score all 3s or all 2s because most newborns vary in development of physical and neuromuscular characteristics, unlike this example.

Some maternal conditions or medications used during labor can affect gestational assessment components and cause the need for further evaluations by the nurse. Maternal diabetes, while it can accelerate fetal physical growth, decelerates fetal maturation. Maternal hypertension usually slows fetal physical growth and accelerates fetal maturation. Use of magnesium sulfate in pregnant people with preeclampsia is correlated with poor muscle tone and edema in newborns. Use of analgesia and anesthesia may cause the newborn to have respiratory depression, and therefore the newborn may show flaccid limbs and demonstrate a frog-like posture. These characteristics affect the neuromuscular portion of the Ballard scoring and should be taken into consideration when the overall scoring is completed.

Estimating by Physical Maturity

The first part of the Ballard Assessment is to observe the newborn without disruption. The following physical characteristics are assessed in specific order from least invasive to more invasive.

Posture

To assess posture, the nurse will assess the newborn lying in the crib in their preferred position. The position of comfort is noted by the nurse on the Ballard Assessment (Figure 23.20). This is a neuromuscular assessment, but the nurse is assessing this during the physical assessment in order not to disrupt the newborn.

Photo of infant lying flat on their back.
Figure 23.20 Newborn Posture The nurse assesses the newborn’s posture in a relaxed state during gestational assessment. (credit: “Back sleep 6” by National Institute of Child Health and Human Development/Flickr, Public Domain)

Skin

Assessment of the skin is a visual assessment. Mature newborn skin loses its protective coating, vernix caseosa. The nurse will see thicker, dryer skin with wrinkles that peels as the newborn matures. In a preterm newborn, the nurse will note that the skin is thin and transparent with veins that are prominent, especially over the abdomen.

Lanugo

Lanugo is fine hair that covers the body of the newborn. In a very premature newborn, the nurse will discover very little lanugo. Lanugo appears at approximately 24 to 25 weeks’ gestation and is most abundant on the back between the scapulae. By the 28th week, it is abundant; and by 38 to 39 weeks, it is mostly gone, disappearing first from the face and then the trunk and extremities (see Table 23.2).

Plantar Surface

This assessment evaluates the plantar surface and the creases on a newborn’s feet. Sole creases appear on the anterior ball of the feet. When the feet begin drying, superficial creases appear, and peeling may occur. Preterm newborns have almost no creases. The nurse measures the distance from the back of the heel to the tip of the great toe.

Breast

The nurses will assess each breast’s diameter in millimeters after inspecting the areola. At term gestation, the tissue should measure between 0.5 and 1 cm (5 to 10 mm). As the gestation progresses, the breast bud and areola enlarge. In a large for gestational age (LGA) newborn, the nurse will note accelerated breast bud development as a reflection of subcutaneous tissue deposits. Small for gestational age (SGA) newborns will have utilized all their subcutaneous tissue to survive in utero and will lack breast tissue (Rosenberg, 2008).

Eyes and Ears

Cartilage in the ears develops with gestational age. Cartilage in the ears is what gives them their shape, so in very premature newborns, the pinna of the ear will remain folded when bent and released. In newborns at less than 34 weeks’ gestation, ears are very flat and have little shape. Additionally, premature newborns may have partially or fully fused eyelids.

Male Genitals

The nurse will assess the male genitals for size of the scrotum, presence of rugae (wrinkles and ridges in the scrotum), and descent of the testicles. During the 30th week of gestation, the testicles descend into the scrotal sac. Before 36 weeks, the scrotum will have very few rugae, and the testes are palpable in the inguinal canal. By term, the testes should have descended, there should be rugae present, and the scrotum should be pendulous.

Female Genitals

Assessment of female genitalia can be difficult due to edema caused by maternal hormones. The clitoris may vary in size. Subcutaneous fat deposition varies as a result of fetal nutritional status, making it difficult sometimes to determine the sex of the newborn. In adrenogenital syndrome (also known as congenital adrenal hyperplasia) excessive amounts of androgen and other hormones are secreted by the adrenal gland and can present as edema of the genitalia. In extremely premature female newborns, the labia are flat, and the clitoris is very prominent. As the infant grows, the labia will grow larger and cover the clitoris.

Estimating by Neuromuscular Maturity

Neuromuscular assessment is best performed when the newborn has stabilized. One significant neuromuscular change is that muscle tone progresses from extensor tone to flexor tone and from the lower to the upper extremities as the neurologic system matures in a tail-to-head progression. In this part of the evaluation, the nurse is looking for responses involving the newborn’s tone.

Square Window Sign

The nurse can assess for the square window sign (measuring wrist flexibility) by flexing the newborn’s hand downward toward the ventral forearm until resistance is felt. The nurse will measure the angle formed at the wrist and document it.

Arm Recoil

To assess for arm recoil (measuring passive flexor tone of biceps), the nurse will place the newborn in a supine position with one of the nurse’s hands beneath the newborn’s elbows for support. The nurses will take the newborn’s hand and briefly set the elbow in flexion, then momentarily extend the arm before releasing the hand. The angle of recoil with which the forearm springs back into flexion is noted.

Popliteal Angle

To assess the popliteal angle, which involves measuring the maturation of passive flexor tone about the knee joint, the nurse must remove the newborn’s diaper and place the newborn in a supine position. Then, the thigh is placed gently on the abdomen, with the knee fully flexed. After the newborn is relaxed in this position, the nurse will gently grasp the foot at the sides with one hand while supporting the thigh with the other. This will be done until a definite angle of extension can be determined. The angle formed at the knee by the upper and lower leg is measured.

Scarf Sign

Assessment of the scarf sign is done to evaluate the passive tone of the flexors above the shoulder girdle. This assessment is completed while the newborn is lying supine, and the nurse adjusts the newborn’s head to a midline position. The nurse gently guides the newborn’s arm over the chest to the other side of the body until resistance is felt. A preterm newborn’s elbow will cross the midline of the chest, whereas a full-term newborn’s elbow will not cross midline.

Heel to Ear

In assessing heel to ear, the nurse places the newborn supine and flexes a lower extremity laterally alongside the body with the palm of their hand. The nurse pulls the newborn’s foot toward the ear of the same side until resistance is felt. A very preterm newborn’s leg will remain straight, and the foot will go to the ear or beyond. With increasing gestational age, the newborn will demonstrate resistance to this maneuver.

Determining the Newborn’s Placement on the CDC Weight Scale

Once the gestational assessment is complete, the nurse will plot the gestational age with the newborn’s length, head circumference, and weight on the appropriate growth chart from the World Health Organization’s growth charts to determine if these measurements fall within range, the 10th to the 90th percentile for the corresponding gestational age based on gender. The placement of the newborn’s data on this growth chart is imperative to monitoring the infant’s weight gain and growth over the first year. The ranges for measurements are grouped as follows:

  • small for gestational age (SGA): a newborn whose weight and/or length measures below the 10th percentile compared to all other newborns their age, according to the CDC growth chart
  • appropriate for gestational age (AGA): a newborn whose weight and/or length measures within the 10th and 90th percentile compared to all other newborns their age, according to the CDC growth chart
  • large for gestational age (LGA): a newborn whose weight and/or length measures above the 90th percentile compared to all other newborns their age, according to the CDC growth chart. (For information on special care of the LGA newborn born to a parent with gestational diabetes, see 25.2 Congenital, Genetic, and Acquired Complications.)

Cultural Context

Cultural Norms Surrounding the Weighing of the Newborn

Most cultures have traditions or beliefs surrounding childbirth and newborn care. One tradition that postpartum nurses may encounter with Hindu parents concerns the weighing of newborns. Nearly two-fifths of Hindu mothers have concerns about babies being weighed regularly or being weighed in front of people. In a survey about this practice, 64 percent of the women said the newborn could not be weighed in front of anyone except the doctor, 27 percent said they did not want the newborn weighed frequently, and 9 percent said they did not want the infant weighed at all in the hospital for fear that the infant would get ill (Upadhayay et al., 2012). It is always best practice for the nurse to assess for any cultural beliefs and practices before doing procedures with the newborn.

Behavioral Assessment of the Newborn: The Brazelton Neonatal Behavioral Assessment

The first few days after birth are a period of behavioral disorganization for the newborn as they adjust to the outside world and its new noises, smells, and sounds. In utero, the newborn only knew muffled sounds and no light or smells; now the newborn is in a sensory-overload environment. As a result, the personality of their newborn may not be readily apparent until day 2 or 3, when they have adjusted to their new environment.

The Brazelton Behavioral Assessment is a psychologic assessment completed on a newborn to assess their capabilities for social relationships (Chin & Teti, 2013). The Brazelton Behavioral Assessment should be completed by the nurse on the second or third day post birth to elicit the best response from the newborn. As newborns are often discharged at 24 hours of life, this assessment may not be performed prior to discharge. This assessment should be completed in a warm, quiet room with as much involvement from the parents as the nurse can incorporate to facilitate parental attachment. The results are relevant up to 2 months of age. The concepts from this behavioral assessment tool have been used by nurses to plan care regarding interactions between newborns and their parents, especially those who are at risk for delayed attachment styles (Chin & Teti, 2013). This assessment’s scale identifies individual differences based on levels of stimulation, handling, and interactions between the newborn and the parent. Four categories are assessed: interactive processes, motoric processes, organizational processes, and physical response to stress. The response is identified as exceptionally good, average, or poor in each of the categories.

The newborn must be in the quiet, alert state when the assessment is performed. The selected maneuvers in the Brazelton scale include having the newborn fix, follow, and find the source of noise and visual stimuli, such as a face or an inanimate object. Demonstrating that the newborn recognizes the parents’ voices and will turn toward them rather than a stranger’s voice is exciting and reassuring for the parents or caregivers to see. During the assessment, the nurse can provide strategies for handling the newborn, soothing and comforting, and pointing out when the newborn is self-soothing. The Brazelton assessment includes four categories, Dimensions I through IV.

Dimension I: Interactive Process

Dimension I: Interactive Process includes assessment of alertness, orientation, and responsiveness to visual and auditory cues. The newborn would receive an exceptionally good score if they could stay alert and focused for most of a 30-minute exam. The newborn would need to focus on an object, turn their head and follow it, and turn their head toward an auditory sound they recognize, like a parent’s voice. A poor score would be given if the newborn did not recognize and acknowledge the auditory cue by turning their head, could not stay awake, and/or was crying and couldn’t be consoled (Basdas et al., 2018).

Dimension II: Motoric Process

Dimension II: Motoric Process focuses on motor tone and the newborn’s activity level. The newborn would score exceptionally well if they had good tone when they were touched or handled by the examiner or parent, could relax in between those interactions, and if they had good reflexes with moderate activity. The newborn would also show head control, hand-to-mouth activity, and no hyper- or hypotonic movements. If the newborn had hyper- or hypo- reflexes, hypo- or hypertonic movements, poor head control, low activity or inconsolability, jerking, tremors, or other immature movements, this would be reflected in poor scores (Basdas et al., 2018).

Dimension III: Organizational Process

Dimension III: Organizational Process assesses the newborn’s ability to achieve and maintain a state of alertness, not be irritable, and not be disturbed by stimuli. To obtain exceptionally good scores, the newborn will need to stay alert and, when drowsy, shut down body responses to stimuli (Basdas et al., 2018). The newborn will demonstrate self-quieting techniques, return to alertness after crying, and have low irritability. Conversely, high irritability or excessively depressed mood would result in low scoring. Flat, depressed newborns would appear drowsy when they were encouraged to wake and be irritable to unpleasant stimuli. High irritability newborns would demonstrate mood swings, inconsolability, and an inability to self-soothe (Basdas et al., 2018).

Dimension IV: Physical Response to Stress

Dimension IV: Physical Response to Stress is focused on physical symptoms in the newborn related to being handled and dressed. If the newborn cries and has significant changes in skin color, a slow recovery of good color, or is startled frequently, this would indicate a poor score. A newborn who has no skin color changes or whose skin recovers quickly from color changes is experiencing good reactions to stress and therefore will receive good scores (Basdas et al., 2018).

Implications and Mitigating Factors for Poor Behavioral Assessment Scores

Some identifiable reasons exist for newborns to score poorly on the behavioral scale and be identified as high-risk. For example, those who are born preterm are more likely to sleep for longer periods. But much more research needs to be done in this area of maternal-child health (Malak et al, 2021). Low-scoring newborns may be hard to wake up to feed, may not bond with parents as easily as other newborns, may have poor breast-feeding initiation and 6-month success rates, and may require early intervention and follow-up (Basdas et al., 2018). Some causal factors for poor scores on the behavioral scale can be phototherapy treatments, excessive maternal medications, low birth weight, young parents, inattentive parenting, inappropriate parental perceptions of infant behaviors, or newborns born to people with narcotic addiction (Basdas et al., 2018).

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