Neonatal mortality in singleton pregnancies: a 20-year retrospective study from a tertiary perinatal unit in Hong Kong.

INTRODUCTION: The global neonatal death (NND) rate has been declining in recent decades, but there are no comprehensive data concerning the characteristics of NNDs in Hong Kong. This study investigated the trends and aetiologies of NNDs among singleton pregnancies in Hong Kong. METHODS: This study included all cases of NND from singleton pregnancies in a tertiary hospital in Hong Kong between 2000 and 2019. The rates, clinical characteristics, and aetiologies of NND were compared between the first (2000-2009) and the second (2010-2019) decades. RESULTS: The NND rate decreased from 1.66/1000 livebirths (97 cases) in the first decade to 1.32/1000 livebirths (87 cases) in the second decade. Congenital or genetic abnormalities (82 cases) caused 44.6% of all NNDs. There was a significant reduction from 0.82/1000 livebirths in the first decade to 0.52/1000 livebirths in the second decade (P=0.037). Other causes of NND were prematurity (69 cases; 37.5%), sepsis (16 cases; 8.7%), hypoxic-ischaemic encephalopathy (15 cases; 8.2%), and sudden infant death syndrome (2 cases; 1.1%). Gestational age-specific neonatal mortality for moderately preterm neonates (31-33 weeks of gestation) significantly decreased from 34.73/1000 in 2000-2009 to 8.63/1000 in 2010-2019 (P=0.001), but there were no significant changes in neonatal mortality for other gestations. CONCLUSION: The NND rate in Hong Kong is among the lowest worldwide. Neonatal deaths in our centre declined over the past two decades, mainly because of improvements in the prenatal diagnosis and treatment of congenital or genetic abnormalities, as well as an improved survival rate among moderately preterm neonates.

Perinatal mortality rate in multiple pregnancies: a 20-year retrospective study from a tertiary obstetric unit in Hong Kong.

INTRODUCTION: Multiple pregnancies have become more common, but their perinatal mortality rate remains higher than the rate among singleton pregnancies. This retrospective study investigated the prevalence and causes of perinatal mortality among multiple pregnancies in Hong Kong. METHODS: All multiple pregnancies in a university tertiary obstetric unit between 2000 and 2019 were reviewed, and the medical records of cases complicated by stillbirth and neonatal death were identified. The causes of perinatal mortality were determined based on clinical assessment and laboratory results, then compared between the first (2000-2009) and second (2010-2019) decades. RESULTS: The prevalence of multiple pregnancies increased from 1.41% in the first decade to 1.91% in the second decade (P<0.001). Compared with the first decade, the second decade had a lower stillbirth rate (14.72 vs 7.68 [both per 1000 births]; P=0.026), late neonatal death rate (4.78 vs 1.16 [both per 1000 livebirths]; P=0.030), and total mortality rate (25.32 vs 13.82 [both per 1000 births]; P=0.006). The decline in stillbirth rate was related to improvements in antenatal care and treatment. The decline in the late neonatal death rate was related to a reduction in preterm birth before 34 weeks (18.5% vs 15.2%; P=0.006), as well as an improvement in the mortality rate in the subgroup of 31-33 weeks (19.23 vs 0 [both per 1000 livebirths]; P=0.035). CONCLUSION: Although the prevalence of multiple pregnancies increased during the study period, the corresponding total perinatal mortality rate improved by 45.4%.

Stillbirth rate in singleton pregnancies: a 20-year retrospective study from a public obstetric unit in Hong Kong.

INTRODUCTION: Although the stillbirth rate is low in Hong Kong, up to 50% of stillbirths have unclassifiable causes and up to one third of stillbirths have unexplained causes. This retrospective study investigated the underlying causes of singleton stillbirths in Hong Kong. METHODS: This study examined the prevalences and causes of stillbirths in a university tertiary obstetric unit between 2000 and 2019. Medical records were reviewed for all singleton pregnancies complicated by stillbirths. Causes of stillbirth were determined via clinical assessments and laboratory findings, then compared between 2000-09 and 2010-19. RESULTS: Overall perinatal mortality significantly decreased by 16.7%, from 5.52/1000 in 2000-09 to 4.59/1000 in 2010-19; the singleton stillbirth rate slightly decreased (from 3.27/1000 to 2.91/1000). These changes were related to early prenatal diagnostic improvements concerning congenital malformations and genetic disorders. Pre-eclampsia prevalence among singleton pregnancies increased from 1.5% to 1.7% because of increasing maternal age; the stillbirth rate among patients with pre-eclampsia decreased from 2.5% to 1.4%. Foetal growth restriction of unknown cause contributed to 16% of all stillbirths; this prevalence did not change over time. Moreover, foetal growth restriction was not diagnosed during routine antenatal care in 43.5% of patients. Thirty-six percent of all stillbirths were unexplained. The prevalences of stillbirth associated with chorioamnionitis and placental abruption did not change over time. CONCLUSIONS: Causes of stillbirth in Hong Kong have changed in the past 20 years because of altered demographic characteristics and improved prenatal testing. Further improvements should focus on early foetal growth restriction detection and preeclampsia prevention.