Intrapartum and delivery room management of the very low birthweight infant

The management of a pregnant woman in premature labor is a challenge. The roles of the perinatologist as well as support people is discussed in this article.     

Aggressive nutrition of the very low birthweight infant

We propose an approach to nutrition of the VLBW infant that aims at minimizing the interruption of nutrient uptake engendered by premature birth. Our approach is aggressive in that it goes beyond current practice in several key aspects. The gap in nutrient intakes between the proposed aggressive approach and current practice will most likely disappear over the next few years as today's aggressive practice becomes tomorrow's standard practice. As the gap diminishes, so will the threat that nutritional deprivation poses to growth and development of VLBW infants.     

Evolution of complete heart block in a fetus and its perinatal management

The antepartum course of a patient with a fetus showing heart block and complex congenital heart disease was followed closely using serial nonstress tests, ultrasonograms, and echocardiograms. Internal fetal heart rate and capillary pH monitoring during labor were useful in guiding the successful vaginal delivery.     

Cerebral palsy in very low birthweight infants surviving to 2 years with modern perinatal intensive care

The rate of cerebral palsy and factors associated with its occurrence were determined in surviving 2-year-old very low birthweight (VLBW) infants born during an era of modern perinatal intensive care. Of the survivors, 12.5% (52/416) of those traced had spastic cerebral palsy. Motor handicaps were mild in 42%, moderate in 25%, and severe in 33% of children with cerebral palsy. The prevalence of cerebral palsy was similar in all birthweight groups up to the upper limit of 1500 gm, and was considerably higher than in survivors born in the same hospital a decade earlier. Although several perinatal variables were associated with the occurrence of cerebral palsy, either singly or in combination, little statistical or clinical confidence would be placed in these associations. Moreover, although 77% of children with cerebral palsy had one or more commonly recognized perinatal risk factors, almost identical rates of risk factors were present in normal children. The advent of cranial ultrasonography during the time of the study was associated with an increase in mortality but no effect on the prevalence of cerebral palsy. Cerebroventricular hemorrhage correlated poorly with the presence of cerebral palsy. The prevalence of cerebral palsy in surviving VLBW infants is unacceptably high; however, no obvious preventable factors in its etiology could be identified.     

Late-onset Mycobacterium abscessus sepsis in a very low birthweight premature infant: diagnostic and therapeutic challenges

Late-onset sepsis (after 3 days of life) is a frequent a complication found in very low birth weight (VLBW, 1000 to 1500 g) premature infants. We report the second case of late-onset sepsis caused by an uncommon pathogen, Mycobacterium abscessus.     

Cerebral pathology in the very low birthweight infant: predictive value of peripartum metabolic acidosis.

One-hundred-and-three infants with a birthweight of less than 1500 g and delivering at a gestation of less than 32 weeks were examined by serial cranial ultrasound scans. A capillary blood sample was drawn for blood gas analysis within 1 h of birth in all cases. The subsequent development of intracranial pathology was found to be significantly associated with gestation at delivery (P less than 0.01), birthweight (P less than 0.01) and base deficit within 1 h of birth (P less than 0.001). For infants with a base deficit of greater than 5.0 mmol/l within the first hour of life, the sensitivity for predicting the subsequent development of cerebral pathology was 51.5% with a specificity of 97.3%, and a positive predictive value of 97.1%. This relationship between a metabolic acidosis within 1 h of birth and the subsequent development of cerebral pathology held for both major and minor degrees of pathology, but was stronger in those infants developing major cerebral pathology. The study suggests that improved surveillance of the very preterm infant during labour and at birth with the aim of reducing the incidence of metabolic acidosis at birth, may help to reduce subsequent intracranial pathology, and thereby perinatal and long-term morbidity.     

Developmental follow-up of very low birthweight premature infants with low free thyroxine.

If a low level of free thyroxine (T4) is predictive of the true hypothyroidism in sick premature infants, long-term developmental follow-up of these infants should reveal a direct correlation between the free thyroxine level early in life and developmental disability in later years. Half of the 16 infants who were followed had normal free T4 (0.8 ng/dl or higher) and the remaining 8 infants had a low free T4 (0.38 +/- 0.15 ng/dl) during the first 2 weeks of life. Infants with low free T4 were followed sequentially during their stay in the neonatal intensive care unit and all eight showed free T4 levels more than 0.8 ng/dl by 36 to 44 weeks postconceptional age without any thyroid replacement. At follow-up, all 16 infants were functioning within normal range by Stanford-Binet testing at mean age of 4.6 years. There was no significant difference between the two groups in their motor development, hearing, language, or physical growth. Despite the small sample size, it appears there is no correlation between the free T4 levels during the first 2 weeks of life in infants 33 weeks' or less gestation and their developmental outcome at mean age of 4.6 years.     

Use of a transparent adhesive dressing in very low birthweight infants

The present study was designed to test the safety and efficacy of a transparent adhesive dressing (TAD) to decrease transepidermal water loss (TEWL) in very low birthweight (VLBW) infants. Thirteen infants with birthweights of 770-1,450 g were randomly assigned to either routine care (n = 7) or TAD (n = 6). There were no differences between the groups with regard to weight at birth, length, head circumference, skinfold thickness measures, and fluid balance at any time during the study period. Electric current used by the radiant warmer operated in the servo-control mode was measured using a clamp-type AC ammeter connected to a single channel recorder. The TAD group used an average of 112 +/- 3.9 watts (n = 30 observation periods), the control group 133 +/- 5.5 (n = 34 observation periods), P = less than .01. TEWL measured by an evaporimeter in four infants of each group was significantly higher in the control group than it was in the TAD group in the area where the skin was covered.     

Optimal ventricular pacing rate in fetal lambs with complete atrioventricular block

OBJECTIVE: This study was undertaken to determine the optimum ventricular pacing rate at which the optimal cardiac function can be attained in fetal lambs with complete atrioventricular block. STUDY DESIGN: Complete atrioventricular block was created by cryosurgery in 12 fetal lambs, and the ventricle was paced randomly at rates of 60, 90, 120, 150, 180, 210, 240, and 270 beats/min. The aortic pressure, central venous pressure, and right ventricular cardiac output were measured before cryosurgery and during ventricular pacing. RESULTS: Complete atrioventricular block was created in 9 of 12 fetal lambs. Systolic aortic pressure significantly decreased at pacing rates of 60, 90 and 240 beats/min (P <.01), and central venous pressure was increased significantly at a pacing rate of 60 beats/min (P <.01) compared with the control. Right ventricular cardiac output significantly decreased at pacing rates of 60, 90, 120, 180, 210, 240, and 270 beats/min (P <.01), although no significant difference was found at the pacing rate of 150 beats/min compared with control. CONCLUSION: Ventricular pacing at a rate of 150 beats/min gave the highest aortic pressure, the lowest central venous pressure, and the highest right ventricular cardiac output in fetal lambs with complete atrioventricular block.     

Extremely low ventricular rate in a fetus with an isolated non-autoimmune complete congenital heart block. Case report

Congenital complete heart block (CCHB) is an uncommon disorder with an incidence of about 1/20,000 in liveborn infants. It can occur in the setting of structurally normal heart or with structural disease; it is associated with high mortality and morbidity and requires a high index of suspicion for early diagnosis and therapy. Isolated CCHB in a fetus is usually associated with the presence of autoantibodies to SSA (Ro) and SSB (La) antigens in the maternal circulation. Such antibodies cross into the fetal circulation and cause inflammation of the conduction tissues; the causal mechanism is not known. Although the prognosis for the majority of fetuses is good, it is less favourable in fetuses with a ventricular rate <55 bpm in early pregnancy or with a decrease in the ventricular rate by >5 bpm during pregnancy. It is not known if the same prognostic criteria apply for fetuses with isolated non-autoimmune CCHB. This article reports authors' experience in managing a pregnancy with an extremely low fetal heart rate (47 bpm) in a single fetus with an isolated non-autoimmune CCHB in which the outcome was favorable.     

Magnetocardiography-guided management of an unusual case of isoimmune complete atrioventricular block complicated by ventricular tachycardia

A fetus who was diagnosed at 25 weeks of gestation with isoimmune AV block presented at 34 weeks with a precipitous fall in ventricular rate and periods of tachycardia. Magnetocardiography revealed the tachycardia to be ventricular. After delivery, nonsustained ventricular tachycardia continued. The baby then successfully paced, and at higher ventricular rates the tachycardia resolved. Five years later the child has normal ventricular function and is doing well.     

Motor development at term of very low birthweight infants with bronchopulmonary dysplasia

Forty-one preterm infants weighing less than 1500 g and less than 32 weeks' gestation at birth had a Dubowitz neurological assessment performed at 40 weeks postconceptional age. The infants were classified into three groups. Eight infants had bronchopulmonary dysplasia and severe central nervous system abnormalities, 11 infants had bronchopulmonary dysplasia alone, and 22 infants had neither bronchopulmonary dysplasia nor severe central nervous system abnormalities. The neuromotor performance of these three groups of infants was similar on all the Dubowitz assessment items at 40 weeks postconceptional age. Neuromotor development of very low birthweight infants with severe bronchopulmonary dysplasia appears to be no different from that of infants without bronchopulmonary dysplasia at 40 weeks postconceptional age utilizing the Dubowitz neurological assessment.     

Delivery of the low birthweight and the very low birthweight breech: cesarean section or vaginal delivery?

We studied neonatal survival rates, APGAR scores, and length of hospital stay in 199 singleton breeches weighing 1000-2500 grams at birth. We found that in the birthweight range of 1000-1750 grams, breeches who were delivered by cesarean section had a significantly higher survival rate (74%) than those who were delivered vaginally (36%, p less than 0.01), however, in the birthweight range of 1751-2500 grams, there was no significant difference in the survival rates between breeches delivered abdominally and those delivered vaginally. The 1-minute and the 5-minute APGAR scores and the length of the hospital stay were not significantly different between the abdominal and the vaginal delivery groups in either birthweight range. The data indicate that the very low birthweight breech (less than or equal to 1750 grams) may benefit from a prophylactic cesarean section.     

Changing diagnosis of cerebral palsy in very low birthweight children

The stability of the diagnosis of cerebral palsy from 2 to 5 years of age was examined in 83 children of birthweight under 1000 gm, and 112 of birthweight 1000 to 1500 gm. In 20 2-year-old children with cerebral palsy, the diagnosis persisted in 11 (55%, 95% confidence intervals 35.1 to 76.9%); 2 of 175 children (1.1%) free of cerebral palsy at 2 years of age subsequently developed the condition. Severe or moderate cerebral palsy at 2 years persisted in all eight children (100%). In 9 of 12 children in whom cerebral palsy at 2 years had disappeared by 5 years, minor neurologic abnormalities and left-hand preference occurred frequently but mean psychologic tests scores were similar to children always free of cerebral palsy. In this cohort, cerebral palsy at 2 years was not a static condition, but overestimated later prevalence.     

Safety of vaginal delivery in very low birthweight vertex singletons: a meta-analysis

Objective: The objective of this study is to assess the safety of vaginal delivery in VLBW singletons in the vertex presentation.

Methods: MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Web of Science databases were searched for studies on mode of delivery and neonatal outcome in VLBW singletons in the vertex presentation. A total of 28 studies met our inclusion criteria.

Results: Vaginal delivery was not associated with an increase in overall neonatal mortality compared with cesarean delivery (OR 0.87, 95% CI 0.72–1.04). Vaginal delivery was associated with a significant decrease in mortality for the 1250–1500?g birthweight category (OR 0.57, 95% CI 0.36–0.92), while an increase in mortality in the 500–750?g category was not significant (OR 1.5, 95% CI 0.86–2.61). Severe intraventricular hemorrhage (IVH) was not associated with mode of delivery (OR 1.05, 95% CI 0.85–1.29), but the only two high quality study that assessed IVH of all grades found an increase in risk for IVH in vaginal delivery (OR 1.33, 95% CI 1.16–1.51).

Conclusions: Vaginal delivery does not appear to increase the risk for neonatal mortality. However, current available data on neonatal morbidity are limited. More high-quality studies are needed to assess the association between mode of delivery and neonatal morbidity.     

Motor system development of the preterm and low birthweight infant

Despite advances in knowledge and technology, accurate prediction of later neuromotor outcomes for infants born preterm remains somewhat elusive. Here we review some of the most recent findings regarding the differential effects of preterm birth and suboptimal fetal growth on neurodevelopment. Evidence from transcranial magnetic stimulation studies is presented that suggests neuromotor development may more directly influence cognitive outcomes than previously recognised. We discuss the role of neuroplasticity in both exacerbating and improving these postnatal outcomes, and possible therapeutic targets for manipulating this. Finally, some developmental care practices that might affect long-term outcomes for these children are discussed.     

The very low birthweight infant: incidence and significance of low Apgar scores, "asphyxia," and morbidity. Findings at delivery

Cord blood gas determinations were made on arterial and venous blood from 78 babies weighing less than 2000 gm at birth, including 52 weighing 1500 gm or less. Correlations were made with Apgar scores and intrapartum events as well as with birthweight (BW) and gestational age (GA). Significant differences were seen between mean BW, GA, and Apgar scores for survivors versus nonsurvivors but only BW and GA were found to affect mortality. The incidence of low Apgar scores, which was high, was inversely related to BW and GA. Correlations between cord blood gases and Apgar scores were poor, most newborns showing normal gases irrespective of Apgar scores. The authors conclude that the term "asphyxia" is an overused explanation for low Apgar scores among very low birthweight babies; they believe it should be reserved for those depressed states proved to be associated with disturbed respiratory physiology.