Perinatal Period Ped9 Perinatal Period



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Perinatal Period Ped9 ()

Perinatal Period

Last updated: September 5, 2017



Delivery Room 2

Evaluation 2



Postdelivery Care 5

Urination 6

Circumcision 6

Defecation 6



Prematurity 7

Postdatism, Postmaturity 13

Small-for-Gestational-Age (SGA, Dysmaturity, Intrauterine Growth Restriction, IUGR) 13

Large-for-Gestational-Age (LGA) 18

Perinatal Asphyxia 19

Newborn resuscitation 22



Hypoxic-Ischemic Encephalopathy (HIE) 29

Treatment 36



Hypothermia 37

Birth Trauma 39

Head Trauma 39

Cranial Nerve Injury 41

Brachial Plexus Injuries 42

Other Peripheral Nerve Injuries 43

Fractures 43

Soft-Tissue Injuries 44

Periventricular / Intraventricular Hemorrhage (PVH-IVH) 44

Periventricular Leukomalacia (PVL) 60


Neonatal Hypoglycemia / Hyperglycemia → see p. 2750 >>

Neonatal Hemolytic Anemias (incl. erythroblastosis fetalis, Rh incompatibility, ABO incompatibility, hydrops fetalis) → see p. 1612 (1-6) >>

Physiologic Anemia of Infancy, Anemia of Prematurity → see p. 1559 (4) >>

Neonatal Blood Loss Anemia → see p. 1557 (2) >>

Neonatal Seizures → see p. E9 >>

Pediatric mortality rates → see p. Ped11 >>

Delivery Room

Evaluation

Apgar score at 1 and 5 min is used to evaluate all newborns immediately after birth (assessment of oxygenation): Dr. Virginia Apgar



criteria

Mnemonic

score

0

1

2

1) color

Appearance

all blue, pale

pink body, blue extremities

all pink

2) heart rate*

Pulse

absent

< 100 / min

> 100 / min

3) reflex response to nasal catheter / tactile stimulation

Grimace

none

grimace

sneeze, cough

4) muscle tone

Activity

limp

some flexion of extremities

active

5) respiration

Respiration

absent

irregular, slow

good, crying

at 1 min: 8-10 - no need for vigorous resuscitation.

5-7 → stimulation and supplemental O2



< 5 → assisted ventilation, possible cardiac support

at 5 min (reflects adequacy of resuscitation and degree of perinatal asphyxia):



7-10 – normal

4-6 – intermediate

0-3 – low

*heart rate obtained by palpating umbilical stump (at level of insertion of infant's abdomen) or by direct auscultation of precordium.



  • many normal newborns have transient cyanosis that clears by 5-min Apgar score!

  • low Apgar score is not per se indicator* of perinatal asphyxia - components of score depend on physiologic maturity, fetal cardiorespiratory and neurologic conditions, and maternal perinatal therapy. *but is associated with risk of long-term neurologic dysfunction

  • infants with prolonged (> 10 min) low Apgar score have progressively increasing mortality in 1st year of life; those who survive may have cerebral palsy.

Additional immediate examination (recommended by Robert A. Hoekelman) when infant does not need immediate resuscitation:

  1. auscultate anterior thorax

  2. palpate abdomen

  3. inspect whole body (incl. oral cavity & perineum)

  4. pass 14 F tube (through nose, nasopharynx, esophagus) into stomach;

    • palpate tube tip in epigastrium or auscultate for bubbling in epigastrium when air is blown through tube;

    • aspirate gastric contents (esp. in prematures or delivered by section) to prevent aspiration;

    • detectable anomalies – posterior choanal atresia*, esophageal atresia**.

*alternatively may be tested by holding infant’s mouth closed and occluding each nostril alternately (N.B. infants cannot breath through mouth [obligate nasal breathers] – pinching both nostrils will cause significant distress!!!)

**suggested by large amount of saliva in mouth.



In addition to Apgar scoring, neonates should be evaluated within 24 hours:

  • evaluation should ideally be performed under radiant warmer with family close by.

for details of examination further see p. Exam11 >>

  1. Gross deformities (e.g. clubfoot, polydactyly), birth trauma and other important abnormalities (such as heart murmurs*).

*murmur heard in first 24 h is most commonly patent ductus arteriosus (murmur usually disappears within 3 days).

9% infants have abnormalities (mainly orthopedic), but many congenital abnormalities cannot be identified during first examination - inform parents that not all problems are evident at birth (record this in writing).



  1. Gestational age (primary determinant of organ maturity!) – when gestational age is uncertain or when infant seems large or small for age; can be determined in days immediately after birth using new Ballard score (typically accurate to ± 2 wk); each neonate is classified: premature, full-term, postmature. see p. Exam11 >>



  1. Body measurements1length, 2weight, 3head circumference are plotted against gestational age. see p. Exam11 >> (for length, weight), p. D5 >> (for head circumference)

    • influenced by genetic factors and intrauterine conditions. also see p. 2735 >>

    • through plotting of weight vs gestational age, each infant is classified:

      1. small for gestational age (SGA) see below >>

      2. appropriate for gestational age (AGA) (growth parameters are between 10th and 90th percentiles for specific time of gestation)

      3. large for gestational age (LGA) see below >>

Body size per se should not be used to infer gestational age or maturation!

N.B. if head circumference is > 90th percentile (regardless of other parameters), specific cerebral pathology should be investigated!

Postdelivery Care

- for term infants with clear amniotic fluid, adequate respiratory effort, and good muscle tone.



  1. clearing of airway (if needed) see below (resuscitation) >>

  2. drying see below (resuscitation) >>

  3. provision of warmth see below (resuscitation) >>

  4. assessing Apgar score. see above >>

  • low-risk delivery team consists of 2 persons: team leader to assess newborn and institute any necessary resuscitation; one assistant to aid in basic newborn resuscitation.

  • neonate is bathed, wrapped, and brought to family.

  • infants should remain with their mothers during and after routine care.

  • head should be covered with cap to prevent heat loss.

  • rooming-in and early breastfeeding should be encouraged.

  • neonates are bathed once their temperature has stabilized at 37° C for 2 h.

  • umbilical cord clamp can be removed when cord appears dry (usually at 24 h);

  • keep umbilical stump clean and dry to prevent infection - some centers apply isopropyl alcohol several times day or single dose of bacteriostatic triple dye.

  • cord is observed daily for redness or drainage (cord is entry portal for infection!!!).

  • neonates discharged within 48 h should be evaluated within 2-3 days to assess feeding success (breast or bottle), hydration, and jaundice (for those at increased risk).

  • term neonates lose 5-8%* of birth weight in first 3 days (urinary and insensible fluid losses, passage of meconium, loss of vernix caseosa, drying of umbilical cord, suboptimal caloric intake). see p. Ped11 >> *prematures - up to 15%

Urination

  • most neonates void within 24 h after birth (average time of 1st void is 7-9 h after birth).

  • most void at least 2 times in 2nd 24 h of life.

  • in 1st 2 days, urine may stain diaper orange / pink (normal urate crystals).

  • delay in voiding ← tight foreskin, posterior urethral valves.

  • normal well hydrated newborn wets ≥ 6-8 diapers per day.

Circumcision

- can be performed (using local anesthesia) within 1st few days of life.



  • decision regarding circumcision is ultimately matter of personal choice, not medical indication.

  • if abnormality of glans / penis is present → delay circumcision (prepuce may be used later in plastic surgical repair).

Circumcision must be delayed until at least first void!

  • circumcision should not be performed if there is risk of bleeding disorders.

  • benefits: circumcision prevents inflammation of glans and prepuce, decreases incidence of penis cancer, UTIs.

  • complications: local infection and bleeding.

Defecation

  • if meconium has not been passed within 24 h after birth → evaluate for anatomic abnormalities (imperforate anus, Hirschsprung's disease, cystic fibrosis).

  • normal newborn defecates after every feeding ÷ once every 4-5 days.

  • breast-fed babies have loose stools with small curds, and bowel movements may be explosive.

Preventive interventions

- see p. 2700 >>



Screenings

- see p. 4800 >>

Prematurity

- infant born before 37 wk gestation; etiology → see p. 2648 >>



Epidemiology

  • ≈ 10% pregnancies in USA (17.9% for black infants).

  • one of chief causes of neonatal morbidity and mortality (incidence of complications and mortality is roughly proportional to degree of prematurity).

Pathophysiology

Organ maturation - structural & functional development.

  • maturation is measured by comparison with adult level of organ function.

  • various organ systems mature at different rates and at different times during gestation.

  • term infant has sufficient function of most organs to allow independent function.

  • some organs (e.g. liver, kidney) accelerate in function during immediate perinatal period, whereas few organs (e.g. brain, lung) continue to mature for many years after birth.

  • preterm infant has inadequate function of some vital organs (e.g. lung) at birth, but within short period of time these organs will have accelerated development* → independent function of preterm infant at gestationally young age.

*i.e. premature birth alters normal sequence of organ maturation.

N.B. neonates < 23-24 weeks' gestation do not have sufficient lung development (absent capillary network adjacent to immature ventilatory units) - cannot survive.



  • close correlation between somatic growth and maturation of vital organs, but various factors may accelerate or retard these processes.

e.g. biochemical lung maturation:

accelerated by fetal malnutrition and betamethasone;

delayed by maternal diabetes (→ fetal hyperinsulinemia).

Clinical Features

- correlate with gestational age:



  1. Low birth weight (< 2500 g)

  2. Physical signs of immaturity:

    1. thin, shiny, dark pink skin through which underlying veins are easily seen.

    2. little subcutaneous fat, hair (but abundant lanugo on back).

    3. ear pinnae are easily folded into various positions without ready recoil.

    4. absent plantar creases.

    5. palpable breast tissue < 1 cm in diameter.

    6. genitalia - scrotum has few rugae, testes may be undescended / labia majora do not yet cover labia minora (labia minora are prominent), prominent clitoris.

    7. “floppy” muscular tone – large range of motion:

  • spontaneous activity↓

  • no flexion of extremities with posture at rest (i.e. extremities are not held in flexed position typical of term infants).

  • scarf sign (elbow easily reaches beyond midline up to anterior axillary line; vs. term infant – cannot reach midline of thorax):



  • heel-to-ear maneuver (heel reaches head while pelvis is held flat):


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