Dataset Information

Temporal trends of preterm birth in Shenzhen, China: a retrospective study.

ABSTRACT: BACKGROUND:Preterm birth is the leading cause of child mortality under 5 years of age. Temporal trends in preterm birth rates are highly heterogeneous among countries and little information exists for China. To address this data gap, we investigated annual changes in preterm birth incidence rate and explored potential determinants of these changes in Shenzhen, China. METHODS:A total of 1.4 million live births, during 2003-2012, were included from the Shenzhen birth registry. Negative-binominal regression models were used to estimate the annual percent changes in incidence. To identify the potential determinants behind temporal trends, we estimated the contribution of each changing risk factor to changes in rate by calculating the difference in population-attributable risk fraction. RESULTS:Annual preterm birth incidence rates increased by 0.94% (95% CI 0.30%, 1.58%) overall, 3.60% (95% CI 2.73%, 4.48%) for medically induced, and 3.13% (95% CI 1.01%, 5.31%) for preterm premature rupture of membranes, but decreased by 2.34% (95% CI 1.62%, 3.06%) for spontaneous preterm labor. Higher maternal educational attainment (0.20 rate increase), lower proportion of inadequate prenatal care (0.15 rate reduction), more multipara (0.08 rate reduction), decreased proportion of preeclampsia or eclampsia (0.05 rate reduction), and larger proportion of young and older pregnant women (0.04 rate increase) were significant contributors to the overall change over time. Contributions of changing risk factors were different between preterm birth subtypes. CONCLUSIONS:Preterm birth rate in Shenzhen, China increased overall during 2003-2012, although trends varied across three preterm birth subtypes. The rising rates were associated with changes in maternal education and age.

SUBMITTER: Li C

PROVIDER: S-EPMC5851155 | biostudies-literature | 2018 Mar

REPOSITORIES: biostudies-literature

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Temporal trends of preterm birth in Shenzhen, China: a retrospective study.

Li Changchang C Liang Zhijiang Z Bloom Michael S MS Wang Qiong Q Shen Xiaoting X Zhang Huanhuan H Wang Suhan S Chen Weiqing W Lin Yan Y Zhao Qingguo Q Huang Cunrui C

Reproductive health 20180313 1

<h4>Background</h4>Preterm birth is the leading cause of child mortality under 5 years of age. Temporal trends in preterm birth rates are highly heterogeneous among countries and little information exists for China. To address this data gap, we investigated annual changes in preterm birth incidence rate and explored potential determinants of these changes in Shenzhen, China.<h4>Methods</h4>A total of 1.4 million live births, during 2003-2012, were included from the Shenzhen birth registry. Negat ...[more]

PMID: 29534760

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Project description:BackgroundNorovirus (NoV) is the main cause of non-bacterial acute gastroenteritis (AGE) outbreaks worldwide. From September 2015 through August 2018, 203 NoV outbreaks involving 2500 cases were reported to the Shenzhen Center for Disease Control and Prevention.MethodsFaecal specimens for 203 outbreaks were collected and epidemiological data were obtained through the AGE outbreak surveillance system in Shenzhen. Genotypes were determined by sequencing analysis. To gain a better understanding of the evolutionary characteristics of NoV in Shenzhen, molecular evolution and mutations were evaluated based on time-scale evolutionary phylogeny and amino acid mutations.ResultsA total of nine districts reported NoV outbreaks and the reported NoV outbreaks peaked from November to March. Among the 203 NoV outbreaks, 150 were sequenced successfully. Most of these outbreaks were associated with the NoV GII.2[P16] strain (45.3%, 92/203) and occurred in school settings (91.6%, 186/203). The evolutionary rates of the RdRp region and the VP1 sequence were 2.1 × 10-3 (95% HPD interval, 1.7 × 10-3-2.5 × 10-3) substitutions/site/year and 2.7 × 10-3 (95% HPD interval, 2.4 × 10-3-3.1 × 10-3) substitutions/site/year, respectively. The common ancestors of the GII.2[P16] strain from Shenzhen and GII.4 Sydney 2012[P16] diverged from 2011 to 2012. The common ancestors of the GII.2[P16] strain from Shenzhen and previous GII.2[P16] (2010-2012) diverged from 2003 to 2004. The results of amino acid mutations showed 6 amino acid substitutions (*77E, R750K, P845Q, H1310Y, K1546Q, T1549A) were found only in GII.4 Sydney 2012[P16] and the GII.2[P16] recombinant strain.ConclusionsThis study illustrates the molecular epidemiological patterns in Shenzhen, China, from September 2015 to August 2018 and provides evidence that the epidemic trend of GII.2[P16] recombinant strain had weakened and the non-structural proteins of the recombinant strain might have played a more significant role than VP1.

Project description:OBJECTIVE: To determine whether a short interval between pregnancies is an independent risk factor for adverse obstetric outcome. DESIGN: Retrospective cohort study. SETTING: Scotland. SUBJECTS: 89 143 women having second births in 1992-8 who conceived within five years of their first birth. MAIN OUTCOME MEASURES: Intrauterine growth restriction (birth weight less than the 5th centile for gestational age), extremely preterm birth (24-32 weeks), moderately preterm birth (33-36 weeks), and perinatal death. RESULTS: Women whose subsequent interpregnancy interval was less than six months were more likely than other women to have had a first birth complicated by intrauterine growth restriction (odds ratio 1.3, 95% confidence interval 1.1 to 1.5), extremely preterm birth (4.1, 3.2 to 5.3), moderately preterm birth (1.5, 1.3 to 1.7), or perinatal death (24.4, 18.9 to 31.5). They were also shorter, less likely to be married, and more likely to be aged less than 20 years at the time of the second birth, to smoke, and to live in an area of high socioeconomic deprivation. When the outcome of the second birth was analysed in relation to the preceding interpregnancy interval and the analysis confined to women whose first birth was a term live birth (n = 69 055), no significant association occurred (adjusted for age, marital status, height, socioeconomic deprivation, smoking, previous birth weight vigesimal, and previous caesarean delivery) between interpregnancy interval and intrauterine growth restriction or stillbirth. However, a short interpregnancy interval (< 6 months) was an independent risk factor for extremely preterm birth (adjusted odds ratio 2.2, 1.3 to 3.6), moderately preterm birth (1.6, 1.3 to 2.0), and neonatal death unrelated to congenital abnormality (3.6, 1.2 to 10.7). The adjusted attributable fractions for these associations were 6.1%, 3.9%, and 13.8%. The associations were very similar when the analysis was confined to married non-smokers aged 25 and above. CONCLUSIONS: A short interpregnancy interval is an independent risk factor for preterm delivery and neonatal death in the second birth.

Project description:Despite decades of attempts to link infectious agents to preterm birth, an exact causative microbe or community of microbes remains elusive. Nonculture 16S ribosomal RNA gene sequencing suggests important racial differences and pregnancy specific changes in the vaginal microbial communities. A recent study examining the association of the vaginal microbiome and preterm birth documented important findings but was performed in a predominantly white cohort. Given the important racial differences in bacterial communities within the vagina as well as persistent racial disparities in preterm birth, it is important to examine cohorts with varied demographic compositions.To characterize vaginal microbial community characteristics in a large, predominantly African-American, longitudinal cohort of pregnant women and test whether particular vaginal microbial community characteristics are associated with the risk for subsequent preterm birth.This is a nested case-control study within a prospective cohort study of women with singleton pregnancies, not on supplemental progesterone, and without cervical cerclage in situ. Serial mid-vaginal swabs were obtained by speculum exam at their routine prenatal visits. Sequencing of the V1V3 region of the 16S rRNA gene was performed on the Roche 454 platform. Alpha diversity community characteristics including richness, Shannon diversity, and evenness as well as beta diversity metrics including Bray Curtis Dissimilarity and specific taxon abundance were compared longitudinally in women who delivered preterm to those who delivered at term.A total of 77 subjects contributed 149 vaginal swabs longitudinally across pregnancy. Participants were predominantly African-American (69%) and had a preterm birth rate of 31%. In subjects with subsequent term delivery, the vaginal microbiome demonstrated stable community richness and Shannon diversity, whereas subjects with subsequent preterm delivery had significantly decreased vaginal richness, diversity, and evenness during pregnancy (P < .01). This change occurred between the first and second trimesters. Within-subject comparisons across pregnancy showed that preterm birth is associated with increased vaginal microbiome instability compared to term birth. No distinct taxa were associated with preterm birth.In a predominantly African-American population, a significant decrease of vaginal microbial community richness and diversity is associated with preterm birth. The timing of this suppression appears early in pregnancy, between the first and second trimesters, suggesting that early gestation may be an ecologically important time for events that ordain subsequent term and preterm birth outcomes.

Project description:ObjectiveAfter a decade of increase, the preterm birth (PTB) rate has declined in the USA since 2006, with the largest decline at late preterm (34-36 weeks). We described concomitant changes in gestational age-specific rates of neonatal mortality and morbidity following spontaneous and clinician-initiated PTB among singleton infants.Design, setting and participantsThis retrospective population-based study included 754?763 singleton births in Washington State, USA, 2004-2013, using data from birth certificates and hospitalisation records. PTB subtypes included preterm premature rupture of membranes (PPROM), spontaneous onset of labour and clinician-initiated delivery.Outcome measuresThe primary outcomes were neonatal mortality and a composite outcome including death or severe neonatal morbidity. Temporal trends in the outcomes and individual morbidities were assessed by PTB subtype. Logistic regression yielded adjusted odds ratios (AOR) per 1?year change in outcome and 95% CI.ResultsThe rate of PTB following PPROM and spontaneous labour declined, while clinician-initiated PTB increased (all p<0.01). Overall neonatal mortality remained unchanged (1.3%; AOR 0.99, CI 0.95 to 1.02), though gestational age-specific mortality following clinician-initiated PTB declined at 32-33 weeks (AOR 0.85, CI 0.74 to 0.97) and increased at 34-36 weeks (AOR 1.10, CI 1.01 to 1.20). The overall rate of the composite outcome increased (from 7.9% to 11.9%; AOR 1.06, CI 1.05 to 1.08). Among late preterm infants, combined mortality or severe morbidity increased following PPROM (AOR 1.13, CI 1.08 to 1.18), spontaneous labour (AOR 1.09, CI 1.06 to 1.13) and clinician-initiated delivery (AOR 1.10, CI 1.07 to 1.13). Neonatal sepsis rates increased among all preterm infants (AOR 1.09, CI 1.08 to 1.11).ConclusionsTiming of obstetric interventions is associated with infant health outcomes at preterm. The temporal decline in late PTB among singleton infants was associated with increased mortality among late preterm infants born following clinician-initiated delivery and increased combined mortality or severe morbidity among all late preterm infants, mainly due to increased rate of sepsis.

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Temporal trends of preterm birth in Shenzhen, China: a retrospective study.

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Temporal trends of preterm birth in Shenzhen, China: a retrospective study.

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