Birth defects in children with newborn encephalopathy.

This study was designed to investigate birth defects found in association with newborn encephalopathy. All possible birth defects were ascertained in a population-based study of 276 term infants with moderate or severe encephalopathy and 564 unmatched term control infants. A strong association between birth defects and newborn encephalopathy was found with defects affecting 27.5% of children with encephalopathy and 4.3% of control children (odds ratio 8.55; 95% confidence interval 5.25 to 13.91;p<0.001). In 11.8% of infants with a birth defect the defect was not diagnosed until after the newborn period, illustrating one of the difficulties in attempting to exclude infants with birth defects from studies of newborn encephalopathy. The majority of defects (89%) were not specific anomalies of the CNS. In 36.8% of children with encephalopthy who had a birth defect, the defect was considered to be the probable cause of the encephalopathy. Infants with birth defects who had encephalopathy had a poorer prognosis than those without: they were twice as likely to die by the age of 2 years and three times more likely to have cerebral palsy. This study catalogues the spectrum of birth defects associated with newborn encephalopathy and illustrates the importance of their inclusion when investigating both the aetiology and outcome of this condition.

Maternal thyroid disease: a risk factor for newborn encephalopathy in term infants.

Two previously published studies of term newborn encephalopathy showed that maternal thyroid disease to be a risk factor. From these studies we identified 13 case and three control mothers with thyroid disease and investigated them further. The majority of affected case mothers had idiopathic or autoimmune hypothyroidism. Compared with control mothers, case mothers had fewer thyroid function tests in pregnancy, were more likely to remain on the same dose of medication throughout pregnancy and to have experienced other pregnancy complications. The association between maternal thyroid disease and encephalopathy may be the result of a series of different causal pathways, some of which are suggested by our data.

Group B streptococcus infection, not birth asphyxia.

This case illustrates 2 main points. Firstly, fetal infection can mimic exactly both the immediate and delayed signs of perinatal asphyxia. Secondly, the placenta may hold the key to the diagnosis of sepsis which may be made difficult in the neonate by labour ward practices such as the use of intrapartum and immediate newborn antibiotics. We strongly support the recommendation that newborn blood and fetal membrane cultures should always be obtained in babies with a diagnosis of 'intrapartum asphyxia and fetal distress' (1). To this we would add the recommendation that placental histology be performed in these circumstances.

Antepartum risk factors for newborn encephalopathy: the Western Australian case-control study.

OBJECTIVE: To ascertain antepartum predictors of newborn encephalopathy in term infants. DESIGN: Population based, unmatched case-control study. SETTING: Metropolitan area of Western Australia, June 1993 to September 1995. SUBJECTS: All 164 term infants with moderate or severe newborn encephalopathy; 400 randomly selected controls. MAIN OUTCOME MEASURES: Adjusted odds ratio estimates. RESULTS: The birth prevalence of moderate or severe newborn encephalopathy was 3.8/1000 term live births. The neonatal fatality was 9.1%. The risk of newborn encephalopathy increased with increasing maternal age and decreased with increasing parity. There was an increased risk associated with having a mother who was unemployed (odds ratio 3.60), an unskilled manual worker (3.84), or a housewife (2.48). Other risk factors from before conception were not having private health insurance (3.46), a family history of seizures (2.55), a family history of neurological disease (2.73), and infertility treatment (4.43). Risk factors during pregnancy were maternal thyroid disease (9.7), severe pre-eclampsia (6.30), moderate or severe bleeding (3.57), a clinically diagnosed viral illness (2.97), not having drunk alcohol (2.91); and placenta described at delivery as abnormal (2.07). Factors related to the baby were birth weight adjusted for gestational age between the third and ninth centile (4.37) or below the third centile (38.23). The risk relation with gestational age was J shaped with 38 and 39 weeks having the lowest risk. CONCLUSIONS: The causes of newborn encephalopathy are heterogeneous and many of the causal pathways start before birth.

Intrapartum risk factors for newborn encephalopathy: the Western Australian case-control study.

OBJECTIVE: To identify intrapartum predictors of newborn encephalopathy in term infants. DESIGN: Population based, unmatched case-control study. SETTING: Metropolitan area of Western Australia, June 1993 to September 1995. SUBJECTS: All 164 term infants with moderate or severe newborn encephalopathy; 400 randomly selected controls. MAIN OUTCOME MEASURES: Adjusted odds ratio estimates. RESULTS: The birth prevalence of moderate or severe newborn encephalopathy was 3.8/1000 term live births. The neonatal fatality was 9.1%. Maternal pyrexia (odds ratio 3.82), a persistent occipitoposterior position (4.29), and an acute intrapartum event (4.44) were all risk factors for newborn encephalopathy. More case infants than control infants were induced (41.5% and 30.5%, respectively) and fewer case infants were delivered by caesarean section without labour (3.7% and 14.5%, respectively). Operative vaginal delivery (2.34) and emergency caesarean section (2.17) were both associated with an increased risk. There was an inverse relation between elective caesarean section (0.17) and newborn encephalopathy. After application of a set of consensus criteria for elective caesarean section only three (7%) eligible case mothers compared with 33 (65%) eligible control mothers were sectioned electively. Of all the case infants, 113 (69%) had only antepartum risk factors for newborn encephalopathy identified; 39 (24%) had antepartum and intrapartum factors; eight (5%) had only intrapartum factors; and four (2%) had no recognised antepartum or intrapartum factors. CONCLUSIONS: The causes of newborn encephalopathy are heterogeneous and many relate to the antepartum period. Elective caesarean section has an inverse association with newborn encephalopathy. Intrapartum hypoxia alone accounts for only a small proportion of newborn encephalopathy. These results question the view that most risk factors for newborn encephalopathy lie in the intrapartum period.

Rising incidence of gastroschisis in teenage pregnancies.

A population-based incidence of gastroschisis using the unique characteristics of a geographically isolated state with a single tertiary obstetric and pediatric hospital has been developed via retrospective data review. Sixty-four cases of gastroschisis were identified during the period 1980 to 1993. With 332,530 deliveries in the 14-year review period, the population incidence of gastroschisis is 1.80 per 10,000 births (95% CI 1.40-2.32). There has been a rise in incidence from 0.48 per 10,000 births in 1980 to 3.16 per 10,000 births in 1993 (NS). This alteration in incidence is an age-group specific event. The age group 15-19 years, which accounts for a consistent 6.5% of total deliveries, has 10 times the incidence of the age range 25-29 years. A sharp rise in the occurrence of gastroschisis in women 15-19 years was observed, with the incidence increasing from 4.0 to 26.5 per 10,000 births over the period of review. Increased use of prenatal ultrasound has made antenatal diagnosis usual and consequent referral to the tertiary referral hospital for delivery. There was a 46% incidence of smoking, and 19% of women admitted to recreational drug use. A strong association with preterm delivery and low birthweight was present with a 50% incidence of low birthweight, eight times the state incidence (OR 14.82, 95% CI 8.97-24.51). The rate of preterm birth was 46.1% vs. 6.6% in the general obstetric population (OR 12.11, 95% CI 6.45-22.73). There was a high incidence of perceived fetal distress, reflected in an increased rate of emergency cesarean section (23% vs. 8%, OR 4.31, 95% CI 1.91-9.74). The early neonatal outcome was satisfactory with three neonatal deaths and an overall perinatal survival rate of 85%. The increase in incidence of gastroschisis in this population-based study reveals a strong association with young maternal age. Investigation into possible etiologic factors to explain this observation is required.

Neonatal subgaleal haematoma: associated risk factors, complications and outcome.

OBJECTIVE: To describe the obstetric and perinatal factors, in particular the method of delivery, associated with development of a subgaleal haematoma (SGH) and to determine the outcome of survivors with this type of birth trauma. METHODOLOGY: Perinatal and obstetric data were retrospectively reviewed for 37 infants admitted to the neonatal unit of the sole tertiary paediatric referral hospital in Western Australia with an SGH, over a 24 year period from 1970 to 1993. These data were compared to data for all Western Australian births. The long-term outcome was obtained through medical and private paediatric records for 26 of these infants. RESULTS: All except one of the neonates had instrumental deliveries; 89% had a vacuum extractor applied to the head at some stage of delivery compared to 10% of the general population of births in Western Australia. There was also a significantly increased risk of failure of attempted vacuum extraction. Of the cases where a vacuum extraction was attempted, 45% also had forceps applied to the head. Coagulopathy was associated with the severity of the SGH. There was also a high frequency of occurrence (40%) of associated head trauma such as intracranial haemorrhage, skull fracture and cerebral oedema, as well as neonatal encephalopathy (73%). The occurrence of these associated features did not correlate significantly with the severity of SGH. Minor complications of SGH included jaundice and facial bruising. There was an excess mortality associated with SGH; however, the long-term outcome for neonatal survivors with this disorder was good. None of the cases studied subsequently developed cerebral palsy or intellectual disability, and minor neurological sequelae only were documented in four infants. CONCLUSIONS: SGH is an uncommon type of birth trauma, and is associated with delivery or attempted delivery by vacuum extraction. The most commonly associated clinical problems were hypovolaemia and coagulopathy. The long-term outcome for neonates with this condition is good.

Predictors of neonatal encephalopathy in full-term infants.

OBJECTIVE: Preliminary investigation of the contribution of adverse antepartum and intrapartum factors to neonatal encephalopathy in singleton neonates born full term. DESIGN: Matched case-control study based on incidence density sampling of controls. SETTING: Two major teaching hospitals (one paediatric and one obstetric) and three peripheral maternity hospitals in Perth, Western Australia (population 1.2 million). SUBJECTS: 89 cases, all the full term singleton neonates born during an eight month period in 1992 who fulfilled one or more of six criteria during the first week of life (seizures, abnormal conscious state, persistent hypertonia or hypotonia, and feeding or respiratory difficulties of central origin). One full term control infant without neonatal encephalopathy was matched to each case by sex, hospital of delivery, time of day and day of the week of birth, and maternal health insurance status. MAIN OUTCOME MEASURES: Odds ratio estimates of relative risk of neonatal encephalopathy associated with antepartum and intrapartum factors. RESULTS: Estimated incidence of moderate or severe encephalopathy in first week of life was 3.75 per 1000 full term live births. Thirteen cases and no controls had evidence suggestive of important intrapartum hypoxia, and in only five of these cases was the neurological condition at birth attributed to events during the intrapartum period. Univariate conditional logistic regression analysis identified significant differences between cases and controls for maternal vaginal bleeding in pregnancy, maternal thyroxine treatment, congenital abnormalities, induction of labour, interval from membrane rupture to delivery, maternal pyrexia in labour, augmentation of labour, abnormal intrapartum cardiotocograms, and meconium in labour. Family history of convulsions also approached significance. CONCLUSIONS: Our preliminary results suggest that intrapartum hypoxia, according to currently used criteria, was not the cause of neonatal encephalopathy in most cases in this population. Our findings suggest that many aetiologies of neonatal encephalopathy originate in the antepartum period.

Neonatal herpes simplex infection: keys to early diagnosis.

OBJECTIVE: To highlight the clinical features of neonatal herpes simplex (HSV) infection that might facilitate earlier diagnosis. METHODOLOGY: Fifteen year retrospective review of proven neonatal HSV cases from a regional neonatal referral unit. RESULTS: Fifteen cases reviewed: 10 with central nervous system (CNS) disease, three with skin, eyes or mouth (SEM) disease and two with disseminated disease (DIS). A median 4 day delay occurred between symptom onset and hospital admission. All cases presented after maternity hospital discharge, most commonly with feeding problems and lethargy. Six patients presented with skin lesions; parental genital herpes was reported in three (20%) cases. Seven infants died, four without acyclovir treatment and three of 11 treated cases. Three of five CNS disease survivors and all infants with SEM disease were normal at follow up. CONCLUSIONS: Acyclovir improves outcome in neonatal HSV infection. To improve outcome further earlier recognition of the non-specific presenting features of the disease is required.

The limitation of referral level fetal ultrasound examination in the detection of spina bifida in Western Australia, 1990-1991.

OBJECTIVE: To ascertain babies born with spina bifida that was not detected by prenatal ultrasound examination performed after 16 weeks' gestational age at Western Australian referral centres, 1990-1991. DESIGN: A retrospective study of the antenatal ultrasound details of those infants born with spina bifida in Western Australia during the 24-month period, 1990 and 1991. Data were collected by interviewing parents, clinically assessing affected individuals and reviewing genetic, clinical and investigative records, and from the Birth Defects Registry of Western Australia. SETTING: Western Australia, which has a relatively high spina bifida birth prevalence of 1 in 1000, has centralised neonatal medical, surgical and genetic services, and a Birth Defects Registry. This enabled us to ascertain all Western Australian neonates with spina bifida for the purposes of this study. There is no universal maternal serum alpha-fetoprotein (MSAFP) screening program and the performance of ultrasonography at referral level is of variable quality. PARTICIPANTS: Newborns with spina bifida and their parents. MAIN OUTCOME MEASURES: Ultrasound screening for spina bifida was deemed to have failed when referral to a specialist imaging centre for the specific purpose of detecting anatomical abnormality after 16 weeks' gestational age gave a falsely negative result. RESULTS: Of the 47 infants born with spina bifida in 1990 and 1991, ultrasound screening at more than 16 weeks' gestational age was documented and was falsely negative in 14. Six of the 14 had a relevant family or medical history for the condition. Five of the lesions were covered and eight of the patients still survive. CONCLUSION: Ad-hoc fetal ultrasound examination via existing referral centres had obvious limitations in detecting spina bifida in a population at low risk. MSAFP screening has a well documented role in detecting neural tube defects, as eight to 10 of the 14 lesions missed by the referral ultrasonography would have been ascertained in a program of this nature. The study indicated that adequate pre-screening clinical histories were not sought, thus limiting the antenatal testing options offered to at-risk couples. This study emphasised the importance of a statewide review of the specificity and sensitivity of the anatomical fetal ultrasound examination, in view of the expansion of this procedure and its variable quality depending on operator experience and equipment quality.

Fast versus slow ventilation for neonates.

To investigate the effect of ventilation rate on respiratory mechanics, 21 neonates ventilated in the neonatal period for various reasons were studied while being ventilated at 30 and 80 breaths/min. Dynamic respiratory system elasticity (ERS), dynamic respiratory system resistance (RRS), and alveolar pressure at end expiration (EEP) were calculated by using multilinear regression to fit the equation of motion of a linear single-compartment model. Technically satisfactory data were obtained from 13 neonates. With the fast ventilation rate, tidal volume and RRS decreased by a mean of 41.3% (p < 0.01) and 17.5% (p < 0.01), respectively, ERS and EEP increased by a mean of 8.3% (p < 0.05) and 22.2% (p < 0.01), respectively. Fast ventilation produced a shorter effective time constant during expiration, limiting the changes in EEP and, hence, in end-expiratory lung volume. The same changes in respiratory mechanics were also observed in neonates who did not show an increase in EEP even at high frequency. These neonates had a high elastance and time constant short enough to ensure adequate lung emptying. These results suggest that the respiratory mechanics of ventilated neonates are frequency dependent and that neonates with higher ERS, such as those with hyaline membrane disease, can cope with fast rate ventilation without developing dynamic hyperinflation.

Ellis-van Creveld syndrome in a Western Australian aboriginal community. Postaxial polydactyly as a heterozygous manifestation?

OBJECTIVE: To report two children with Ellis-van Creveld syndrome in an extended kindred of Western Australian Aboriginal descent. Furthermore, to document two family members with isolated postaxial polydactyly of the feet as probable heterozygous manifestations of the Ellis-van Creveld gene. CLINICAL FEATURES: Male and female second cousins with short limbs, postaxial polydactyly and cardiac malformations are described. CONCLUSIONS: It is proposed that founder effect and random genetic drift resulted in a relatively high frequency of the Ellis-van Creveld gene in the Aboriginal people of Western Australia. In addition, further evidence is provided for the postulate that isolated postaxial polydactyly is a heterozygous manifestation of the gene.

Hirschsprung's disease and Ondine's curse: further evidence for a distinct syndrome.

Although Hirschsprung's disease is a relatively common congenital malformation, with an estimated incidence of about 1:5000, Primary Central Hypoventilation Syndrome (Ondine's curse) is exceedingly rare, with about 50 reported cases. We describe a patient with total colonic aganglionosis occurring together with failure of automatic control of respiration, specific facial dysmorphology and characteristic CT scan changes to substantiate further the syndromic nature of this association.

Primary anastomosis for necrotising enterocolitis: a 12-year experience.

Between January 1975 and October 1987, 50 cases of necrotising enterocolitis (NEC) have required surgery. The principle that the best management is resection and exteriorisation of the ends, which was developed in the early 1970s, has been superseded by the realisation that resection and primary anastomosis can be safe in a well-resuscitated infant in whom the bowel ends appear viable. Eight babies had widespread NEC and no procedure was performed. Thirteen babies had resection and exteriorisation with five long-term survivors (39%). Twenty-nine babies had a primary anastomosis irrespective of birth weight, gestational age, length of resection, or the presence of peritonitis--with 22 (76%) long-term survivors. The pre-operative risk factors and length of bowel resected were similar in the two groups. The length of hospital stay, the period of total parenteral nutrition, the time to full feeds, and the time on a ventilator were all shorter in the primary anastomosis group, with no increase in short- or long-term morbidity or mortality. Provided that the bowel ends are viable, primary anastomosis is the procedure of choice for babies with NEC requiring laparotomy.