Antenatal care, identification of suboptimal fetal growth and risk of late stillbirth: findings from the Auckland Stillbirth Study.

INTRODUCTION: Stillbirth remains an important public health problem in Australia and New Zealand. The role that antenatal care plays in the prevention of stillbirth in high-income countries is unclear. METHODS: Cases were women with a singleton, late stillbirth without congenital abnormality, booked to deliver in the Auckland region and born between July 2006 and June 2009. Two controls with ongoing pregnancies were randomly selected at the same gestation at which the stillbirth occurred. Data were collected through interview-administered questionnaires and from antenatal records. RESULTS: One hundred and fifty five of 215 (72%) cases and 310 of 429 (72%) controls consented to take part in the study. Accessing <50% of recommended antenatal visits was associated with a more than twofold increase in late stillbirth (adjusted odds ratio, aOR, 2.68; 95% CI, 1.04-6.90) compared with accessing the recommended number of visits. Small-for-gestational-age (SGA) babies that had not been identified as SGA prior to birth were significantly more at risk of being stillborn (aOR, 9.46; 95% CI, 1.98-45.13) compared with SGA babies that were identified as such in the antenatal period. No relationship was found between type or model of maternity care provider at booking and late stillbirth risk. DISCUSSION: This study reinforces the importance of regular antenatal care attendance. Identification of SGA may be one way by which antenatal care reduces stillbirth.

Relationship between obesity, ethnicity and risk of late stillbirth: a case control study.

BACKGROUND: In high income countries there has been little improvement in stillbirth rates over the past two decades. Previous studies have indicated an ethnic disparity in the rate of stillbirths. This study aimed to determine whether maternal ethnicity is independently associated with late stillbirth in New Zealand. METHODS: Cases were women with a singleton, late stillbirth (≥ 28 weeks' gestation) without congenital abnormality, born between July 2006 and June 2009 in Auckland, New Zealand. Two controls with ongoing pregnancies were randomly selected at the same gestation at which the stillbirth occurred. Women were interviewed in the first few weeks following stillbirth, or at the equivalent gestation for controls. Detailed demographic data were recorded. The study was powered to detect an odds ratio of 2, with a power of 80% at the 5% level of significance, given a prevalence of the risk factor of 20%. A multivariable regression model was developed which adjusted for known risk factors for stillbirth, as well as significant risk factors identified in the current study, and adjusted odds ratios and 95% confidence intervals were calculated. RESULTS: 155/215 (72%) cases and 310/429 (72%) controls consented. Pacific ethnicity, overweight and obesity, grandmultiparity, not being married, not being in paid work, social deprivation, exposure to tobacco smoke and use of recreational drugs were associated with an increased risk of late stillbirth in univariable analysis. Maternal overweight and obesity, nulliparity, grandmultiparity, not being married and not being in paid work were independently associated with late stillbirth in multivariable analysis, whereas Pacific ethnicity was no longer significant (adjusted Odds Ratio 0.99; 0.51-1.91). CONCLUSIONS: Pacific ethnicity was not found to be an independent risk factor for late stillbirth in this New Zealand study. The disparity in stillbirth rates between Pacific and European women can be attributed to confounding factors such as maternal obesity and high parity.

The Auckland Stillbirth study, a case-control study exploring modifiable risk factors for third trimester stillbirth: methods and rationale.

BACKGROUND: In high-income countries, stillbirth rates have been static in recent decades. Unexplained stillbirths account for up to 50% of these deaths. METHODS: A case-control study was conducted in Auckland, New Zealand, from July 2006 to June 2009 to explore modifiable risk factors for late stillbirth (≥28 weeks of gestation). Eligible participants were women who had a singleton late stillbirth without a congenital abnormality. Two controls with ongoing pregnancies were randomly selected at the same gestation as each case. Data were collected through face-to-face interviews and from clinical records. RESULTS: A total of 155/215 (72%) cases and 310/429 (72%) controls consented to take part in the study. Women who had a late stillbirth were more likely to be of Pacific ethnicity and of parity ≥4 (OR = 1.7, 95% CI: 1.1-2.6 and 2.7, 95% CI: 1.4-5.3, respectively). The median gestational age at diagnosis of fetal death was 261 days (IQR 239-279), and the median gestation at which the controls were interviewed was 264.5 days (IQR 240-274) P = 0.48. 'Unexplained antepartum death' (n = 61, 39.4%) and 'fetal growth restriction' (n = 29, 18.7%) accounted for almost 60% of stillbirths. The post-mortem rate for all cases was 47% (73/155) and 43% (26/61) for those classified as 'unexplained antepartum death'. CONCLUSION: This study of risk factors for stillbirth is novel in that it used gestation-matched controls with ongoing pregnancies. Its detailed investigation into maternal health and behaviour during pregnancy has the potential to lead to a better understanding of modifiable risk factors for late stillbirth.

Forensic issues in cases of water birth fatalities.

Birth under water has become a widely disseminated technique that is promoted to improve the quality of labor. The case of a 42-week gestation male infant is reported who died of respiratory and multiorgan failure secondary to florid pneumonia and sepsis due Pseudomonas aeruginosa following a water birth. Other infants who have been delivered underwater have drowned or have had near-drowning episodes with significant hyponatremia and water intoxication. Local and disseminated sepsis has been reported, with respiratory distress, fevers, hypoxic brain damage, and seizures. There have also been episodes of cord rupture with hemorrhage. The postmortem investigation of such cases requires a complete autopsy of the infant, with examination of the placenta. Full details of the pregnancy and delivery and inspection of the birthing unit are also needed. A septic workup of the infant and placenta should be undertaken along with sampling of water from the birthing unit and microbiological swabbing of the equipment. Vitreous sodium levels may reveal electrolyte disturbances. While fatal cases appear rare, this may change if water births gain in popularity.

Risk factors for and timing of death of extremely preterm infants.

This study examined risk factors for timing and cause of death for extremely preterm infants > or = 23 weeks and < 28 weeks. There were 479 liveborn infants and 98 deaths reviewed over a ten-year period. Thirty-two deaths (33%) occurred on the first day of life and 72 (75%) in the first month of life. Lower gestation and intrauterine growth restriction were significant risk factors for death. Most deaths occurred in the first month of life and at the lowest gestation in the first week.

Association between maternal sleep practices and risk of late stillbirth: a case-control study.

OBJECTIVES: To determine whether snoring, sleep position, and other sleep practices in pregnant women are associated with risk of late stillbirth. DESIGN: Prospective population based case-control study. SETTING: Auckland, New Zealand CASES: 155 women with a singleton late stillbirth (≥ 28 weeks' gestation) without congenital abnormality born between July 2006 and June 2009 and booked to deliver in Auckland. CONTROLS: 310 women with single ongoing pregnancies and gestation matched to that at which the stillbirth occurred. Multivariable logistic regression adjusted for known confounding factors. MAIN OUTCOME MEASURE: Maternal snoring, daytime sleepiness (measured with the Epworth sleepiness scale), and sleep position at the time of going to sleep and on waking (left side, right side, back, and other). RESULTS: The prevalence of late stillbirth in this study was 3.09/1000 births. No relation was found between snoring or daytime sleepiness and risk of late stillbirth. However, women who slept on their back or on their right side on the previous night (before stillbirth or interview) were more likely to experience a late stillbirth compared with women who slept on their left side (adjusted odds ratio for back sleeping 2.54 (95% CI 1.04 to 6.18), and for right side sleeping 1.74 (0.98 to 3.01)). The absolute risk of late stillbirth for women who went to sleep on their left was 1.96/1000 and was 3.93/1000 for women who did not go to sleep on their left. Women who got up to go to the toilet once or less on the last night were more likely to experience a late stillbirth compared with women who got up more frequently (adjusted odds ratio 2.28 (1.40 to 3.71)). Women who regularly slept during the day in the previous month were also more likely to experience a late stillbirth than those who did not (2.04 (1.26 to 3.27)). CONCLUSIONS: This is the first study to report maternal sleep related practices as risk factors for stillbirth, and these findings require urgent confirmation in further studies.

Sudden unexpected infant death and bedsharing: referrals to the Wellington Coroner 1997-2006.

AIMS: To describe the factors associated with sudden unexpected infant deaths, for which there was no clear medical diagnosis, referred to the Wellington-based coronial paediatric pathology service over the decade from 1997 to 2006. METHODS: The postmortem report, Police 47 file, Coroner's findings and deceased infant's medical records were used to create a profile for each sudden and unexpected infant death. RESULTS: There were 64 deaths in the period: 54 of these occurred during sleep and did not have a clear medical diagnosis. Maori and Pacific infants and infants from low decile areas were over-represented in the group. The majority (88.7%) of infants were < 6 months of age at death. Overall, 50% of infants had been placed to sleep in a non-recommended sleep position and 38% usually slept in a non-recommended location. Bedsharing was associated with 53.7% of deaths. There was a significant association between bedsharing and being found dead on a Sunday morning (p=0.04). CONCLUSION: Sudden unexpected death in infancy is associated with unsafe sleep environments and sleep positions. Every effort should be made to ensure that information about safe infant sleep practices reaches the caregivers of those particularly at risk.

Failure of apnea monitoring during bed-sharing.

We report the case of an infant found dead in bed with an adult while attached to a respiratory monitor sensor. We experimentally re-created a bed-sharing situation with an infant mannequin to demonstrate that a Graseby home apnea monitor continues to sense adult breathing and movement in the absence of infant breathing when used in this sleep situation.

Neonatal death after hypoxic ischaemic encephalopathy: does a postmortem add to the final diagnoses?

BACKGROUND: Case review after fatal perinatal asphyxia may have medicolegal implications. Accurate diagnosis of cause of death is therefore essential. OBJECTIVE: To determine consent rate and utility of autopsy after fatal grade III hypoxic ischaemic encephalopathy (HIE) presumed to be secondary to birth asphyxia. DESIGN: A retrospective clinical review from January 1995 to December 2002. SETTING: Regional tertiary referral neonatal unit, Wellington, New Zealand. POPULATION: Inclusion criteria were gestation >/=37 weeks, resuscitation after delivery and clinical course of grade III HIE. Exclusions were a recognised major lethal malformation. METHODS: Review of clinical records including the autopsy report. MAIN OUTCOME MEASURES: Consent for autopsy, change in diagnosis after autopsy. RESULTS: Twenty-three infants died during the time period with a major diagnosis of grade III HIE. Three did not meet inclusion criteria. Of the remaining 20, 11 were female. Median gestation at birth was 40 weeks (range 38-42 weeks) and median birth weight was 3568 g (range 2140-4475 g). In 8/17 of the infants for whom length and head measurements were available, the Ponderal Index suggested intrauterine growth retardation. The 16/20 infants had an autopsy. Four of these were Coroner's cases giving an autopsy rate of 80% with a rate by consent of 60%. In 10 (62.5%) infants, significant new information was added to the clinical diagnoses. CONCLUSIONS: Neonatal HIE is a symptom rather than a final clinical diagnosis. A full autopsy is required to fully explore the reasons for fatal neonatal HIE and may provide information that is important medicolegally.

Histopathology and ultrastructure of human umbilical blood vessels.

To resolve controversy over umbilical vessels structure, a morphological review was undertaken of the histology of blood vessels in 130 fetal umbilical cords varying in gestational age and the ultrastructure of blood vessels in 6 umbilical cords. Arteries and veins were lined by endothelium. The internal elastic lamina was frequently interrupted when associated with intimal thickening of longitudinally orientated smooth muscle cells. Fragments of elastic laminae developed in the intima and inner media both of which were thicker in arteries than in vein. No external elastic laminae or distinct adventitia were found. Most notable was the accumulation of cell debris developed from blebs derived from polypoid cytoplasmic protrusions of smooth muscle cells of both arteries and veins. They underwent hydropic change and became detached and fragmented particularly after 20 weeks' gestation. Similar hydropic degeneration occurred in endothelial cells of arteries and veins, such changes being consistent with the destructive pattern of hemodynamic stresses.