Preterm birth and neonatal mortality in China in 2011

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

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.

Maternal exposure to nickel in relation to preterm delivery

Prior studies have suggested the reproductive effects of nickel; however, few epidemiological studies have investigated the associations of maternal exposure to nickel with preterm delivery. To investigate prenatal exposure to nickel as a risk factor for preterm delivery (< 37 weeks) in a large birth cohort. A total of 7291 pregnant women participated in the study were recruited between September 2012 and October 2014 in the longitudinal Healthy Baby Cohort (HBC) in Wuhan, China. Inductively Coupled Plasma Mass Spectrometry was employed to examine levels of nickel in urine from pregnant women collected before labor. The median urinary creatinine-corrected nickel was 5.05 creatinine μg/g with an inter-quartile range of 2.65-9.51 creatinine μg/g. We adjusted for potential confounders and found that each doubling in concentration of maternal urinary nickel was associated with an increase of 16% in adjusted odds ratios (ORs) for preterm delivery (95% CI: 1.08, 1.24). The associations were consistent for both spontaneous and iatrogenic preterm delivery. Our findings suggest that higher maternal urinary nickel concentrations were associated with an increased risk of preterm delivery.

[Application of movement recognition technology in assessing spontaneous general movements in preterm infants]

Preterm birth is a major factor which induces neurological and motor impairments, particularly cerebral palsy, in high-risk infants. Early identification of potential neurodevelopmental impairments provides the opportunity to improve neurodevelopmental outcomes in preterm infants through early rehabilitation interventions. Clinically, the general movement assessment is a pivotal tool to predict neurodevelopmental outcomes, especially motor developmental outcomes, in high-risk infants. Movement recognition can continuously capture relevant limb movements and perform objective and quantitative assessment using computerized approaches. Various methods of recording and analyzing spontaneous general movements for infants at a risk of cerebral palsy have been extensively explored. This article summarizes the general movement assessment method and reviews the translational research on using movement recognition technology for the assessment of spontaneous general movements of preterm infants.

New model for predicting preterm delivery during the second trimester of pregnancy

In this study, a new model for predicting preterm delivery (PD) was proposed. The primary model was constructed using ten selected variables, as previously defined in seventeen different studies. The ability of the model to predict PD was evaluated using the combined measurement from these variables. Therefore, a prospective investigation was performed by enrolling 130 pregnant patients whose gestational ages varied from 17⁺⁰ to 28⁺⁶ weeks. The patients underwent epidemiological surveys and ultrasonographic measurements of their cervixes, and cervicovaginal fluid and serum were collected during a routine speculum examination performed by the managing gynecologist. The results showed eight significant variables were included in the present analysis, and combination of the positive variables indicated an increased probability of PD in pregnant patients. The accuracy for predicting PD were as follows: one positive – 42.9%; two positives – 75.0%; three positives – 81.8% and four positives – 100.0%. In particular, the combination of ≥2× positives had the best predictive value, with a relatively high sensitivity (82.6%), specificity (88.1%) and accuracy rate (79.2%), and was considered the cut-off point for predicting PD. In conclusion, the new model provides a useful reference for evaluating the risk of PD in clinical cases.

Does tea consumption during early pregnancy have an adverse effect on birth outcomes?

BACKGROUND

Tea, a common beverage, has been suggested to exhibit a number of health benefits. However, one of its active ingredients, caffeine, has been associated with preterm birth and low birthweight. We investigated whether tea consumption during early pregnancy is associated with an increased risk of preterm birth and abnormal fetal growth.

METHODS

A total of 8775 pregnant women were included from the Born in Guangzhou Cohort Study. Tea consumption (type, frequency, and strength) during their first trimester and social and demographic factors were obtained by way of questionnaires administered during pregnancy. Information on birth outcomes and complications during pregnancy was obtained from hospital medical records.

RESULTS

Overall habitual tea drinking (≥1 serving/week) prevalence among pregnant women was low, at 16%. After adjustment for potential confounding factors (eg, maternal age, educational level, monthly income) tea drinking during early pregnancy was not associated with an increased risk of preterm birth or abnormal fetal growth (small or large for gestational age) (P>.05).

CONCLUSIONS

We did not identify a consistent association between frequency of tea consumption or tea strength and adverse birth outcomes among Chinese pregnant women with low tea consumption. Our findings suggest that occasional tea drinking during pregnancy is not associated with increased risk of preterm birth or abnormal fetal growth. Given the high overall number of annual births in China, our findings have important public health significance.

Effects of Prenatal Micronutrient Supplementation on Spontaneous Preterm Birth: A Double-Blind Randomized Controlled Trial in China

In this secondary analysis of data from a double-blind randomized controlled trial carried out in northern China, we aimed to assess the effect of prenatal supplementation with multiple micronutrients (MMN) or iron + folic acid (IFA), versus folic acid (FA) alone, on risk of spontaneous preterm birth (SPB) and the impact of supplementation timing on SPB. A total of 18,775 nulliparous pregnant women enrolled between 2006 and 2009 were randomly assigned to receive daily FA, IFA, or MMN from the period before 20 weeks' gestation to delivery. The incidences of SPB for women consuming FA, IFA, and MMN were 5.7%, 5.6% and 5.1%, respectively. Compared with women given FA, the relative risks of SPB for those using MMN and IFA were 0.99 (95% confidence interval: 0.85, 1.16) and 0.89 (95% confidence interval: 0.79, 1.05), respectively. SPB incidence in women who started consuming FA, IFA, and MMN before the 12th week of gestation (4.6%, 4.2%, and 3.9%, respectively) was significantly reduced compared with starting supplement use on or after the 12th gestational week (6.9%, 7.2%, and 6.4%, respectively). Starting use of FA, IFA, or MMN supplements before the 12th week of gestation produced a 41%-45% reduction in risk of SPB. Early prenatal enrollment and micronutrient use during the first trimester of pregnancy appeared to be of particular importance for prevention of SPB, regardless of supplement group.

[Mortality rate and cause of death in hospitalized neonates: an analysis of 480 cases]

OBJECTIVE

To investigate the mortality rate and the cause of death of hospitalized neonates.

METHODS

The clinical data of 480 neonates who died between January 2008 and December 2014 were collected. The mortality rates of neonates with different gestational ages, birth weights, sexes, and ages in days were analyzed. The abnormal perinatal factors, cause of death, and death grade were summarized.

RESULTS

Among the 41 910 hospitalized neonates, 480 (1.1%) died, and the mortality rates of preterm infants and full-term infants were 1.7% and 0.7%, respectively. The mortality rate of hospitalized neonates decreased from 1.4% in 2008 to 1.1% in 2014, and the decrease was more apparent in the preterm infants with a gestational age of <32 weeks and the neonates with a birth weight of <1 000 g. Among preterm infants and full-term infants, those with a lower gestational age tended to have a higher mortality rate, but post-term infants had an increased mortality rate. The infants with a lower birth weight tended to have a higher mortality rate. Male neonates had a significantly higher mortality rate than female neonates (1.31% vs 0.92%; P<0.05). Among the neonates who died, 61.3% had definite abnormal perinatal factors, including abnormal amniotic fluid (29.4%), premature rupture of membranes (16.9%), placental abnormality (16.9%), fetal intrauterine distress (14.0%), and abnormal umbilical cord (12.3%). Among the 480 neonates who died, 57 (11.9%) died within 24 hours after birth, 181 (37.7%) died within 2-7 days, and 242 (50.4%) died within 8-28 days. The three most common causes of death were infection, birth defect, and respiratory distress syndrome. The most common cause of death was respiratory distress syndrome in 2008-2011 and infection in 2012-2014. Respiratory distress syndrome was the most common cause of death in preterm infants with a gestational age of <32 weeks, neonates with a birth weight of <1 500 g, and neonates who died with 24 hours; infection was the most common cause of death in neonates with a gestational age of 32-42 weeks, neonates with a birth weight of 1 500-4 000 g, and neonates who died within 8-28 days. Neonatal asphyxia was the major cause of death in post-term infants. Inevitable deaths (grade 1) accounted for 54.4%, deaths that could be avoided under certain conditions (grade 2) accounted for 23.3%, and deaths caused by concerns about prognosis or economic reasons (grade 3) accounted for 22.3%.

CONCLUSIONS

In recent years, the treatment of neonates has gradually improved, and the mortality rate of neonates is gradually decreasing, especially in neonates with low gestational age and birth weight. Important measures for reducing the mortality rate in neonates include enhancing perinatal management, reducing abnormal perinatal factors, preventing infection, and increasing parents' confidence in treatment.

Delivery modes and pregnancy outcomes of low birth weight infants in China

OBJECTIVE

To investigate and analyze the perinatal outcomes of low birth weight (LBW) infants, thereby selecting the appropriate mode and suitable time of delivery to improve the adverse pregnancy outcomes.

STUDY DESIGN

A retrospective analysis of 112,441 deliveries (from 39 hospitals of different levels in 14 provinces and autonomous regions in China throughout 2011) were performed in this study to further evaluate the modes of delivery and pregnancy outcomes of LBW infants.

RESULTS

The rate of cesarean section, stillbirth, neonatal asphyxia and mortality of LBW were significantly higher than those of normal birth weight (NBW) infants (odds ratio, 1.24, 56.56, 57.27 and 10.40 times higher, respectively). Stratified analysis showed that adverse events were reduced with the increase in gestational weeks, especially at 34 to 36(+6) weeks. However, LBW infants still had higher risks of adverse events as compared with NBW infants. In particular, full-term LBW babies had a 23.81- and 26.06-fold higher risk of stillbirth and neonatal death as compared with term babies with NBW. In addition, the cesarean delivery rate was 1.24-fold higher for LBW babies than for NBW babies. With an increase in gestational age in LBW infants, the rate of cesarean section was also increased. The rates of stillbirth and neonatal mortality of full-term LBW infants who were delivered via cesarean section (0.5% and 1.0%, respectively) were significantly lower than in the vaginal-delivery group (5.2% and 6.9%, respectively).

CONCLUSION

LBW is one of the causes of perinatal death and other adverse pregnancy outcomes and increases the rate of cesarean section. Individualized analysis according to gestational age and intrauterine fetal condition should be performed to extend the gestational age to at least 34 weeks before delivery, cesarean section is a relatively safe mode of delivery, but cannot completely eliminate complications. The key to improving mother and child outcomes is to strengthen pregnancy care and reduce low birth weight infants and premature birth. LBW is one of the causes of adverse pregnancy outcomes in both premature and full-term infants and increases the rate of cesarean section. Individualized analysis of the mode of delivery should be performed to extend the gestational age to 34 weeks and so improve the survival rate.

Time trends and risk factor associated with premature birth and infants deaths due to prematurity in Hubei Province, China from 2001 to 2012

Background

The nutrition and epidemiologic transition has been associated with an increasing incidence of preterm birth in developing countries, but data from large observational studies in China have been limited. Our study was to describe the trends and factors associated with the incidence of preterm birth and infant mortality due to prematurity in Hubei Province, China.

Methods

We conducted a population-based survey through the Maternal and Child Health Care Network in Hubei Province from January 2001 to December 2012. We used data from 16 monitoring sites to examine the trend and risk factors for premature birth as well as infant mortality associated with prematurity.

Results

A total of 818,481 live births were documented, including 76,923 preterm infants (94 preterm infants per 1,000 live births) and 2,248 deaths due to prematurity (2.75 preterm deaths per 1,000 live births). From 2001 to 2012, the incidence of preterm birth increased from 56.7 to 105.2 per 1,000 live births (P for trend < 0.05), while the infant mortality rate due to prematurity declined from 95.0 to 13.4 per 1,000 live births (P for trend < 0.05). Older maternal age, lower maternal education, use of assisted reproductive technology (ART), higher income, residence in urban areas, and infant male sex were independently associated with a higher incidence of preterm birth (all p values < 0.05). Shorter gestation, lower birth weight, and lower income were associated with a higher mortality rate, while use of newborn emergency transport services (NETS) was associated with a lower preterm mortality rate (all p values < 0.05).

Conclusion

An increasing incidence of preterm birth and a parallel reduction in infant mortality due to prematurity were observed in Hubei Province from 2001 to 2012. Our results provide important information for areas of improvements in reducing incidence and mortality of premature birth.

Electronic supplementary material

The online version of this article (doi:10.1186/s12884-015-0767-x) contains supplementary material, which is available to authorized users.

Soluble receptors for advanced glycation end products and receptor activator of NF-κB ligand serum levels as markers of premature labor

Background

This study aimed to determine the relationships between secretory and endogenous secretory receptors for advanced glycation end products (sRAGE, esRAGE), sRANKL, osteoprotegerin and the interval from diagnosis of threatened premature labor or premature rupture of the fetal membranes to delivery, and to evaluate the prognostic values of the assessed parameters for preterm birth.

Methods

Ninety women between 22 and 36 weeks’ gestation were included and divided into two groups: group A comprised 41 women at 22 to 36 weeks’ gestation who were suffering from threatened premature labor; and group B comprised 49 women at 22 to 36 weeks’ gestation with preterm premature rupture of the membranes. Levels of sRAGE, esRAGE, sRANKL, and osteoprotegerin were measured. The Mann–Whitney test was used to assess differences in parameters between the groups. For statistical analysis of relationships, correlation coefficients were estimated using Spearman’s test. Receiver operating characteristics were used to determine the cut-off point and predictive values.

Results

In group A, sRAGE and sRANKL levels were correlated with the latent time from symptoms until delivery (r = 0.422; r = −0.341, respectively). The sensitivities of sRANKL and sRAGE levels for predicting preterm delivery were 0.895 and 0.929 with a negative predictive value (NPV) of 0.857 and 0.929, respectively. In group B, sRAGE and sRANKL levels were correlated with the latent time from pPROM until delivery (r = 0.381; r = −0.439). The sensitivity of sRANKL and sRAGE for predicting delivery within 24 h after pPROM was 0.682 and 0.318, with NPVs of 0.741 and 0.625, respectively. Levels of esRAGE and sRANKL were lower in group A than in group B (median = 490.2 vs 541.1 pg/mL; median = 6425.0 vs 11362.5 pg/mL, respectively).

Conclusions

Correlations between sRAGE, sRANKL, and pregnancy duration after the onset of symptoms suggest their role in preterm delivery. The high prognostic values of these biomarkers indicate their usefulness in diagnosis of pregnancies with threatened premature labor.

Preconception blood pressure and risk of preterm birth: a large historical cohort study in a Chinese rural population

OBJECTIVE

To examine the relationship between preconception blood pressure (BP) and the risk of preterm birth (PTB) using a historical cohort of reproductive-aged women and girls from a Chinese rural population.

DESIGN

A historical cohort study established between 2010 and 2013 in People's Republic of China.

SETTING

Local family-planning service agencies and maternal-child care service centers.

PATIENT(S)

A total of 367,425 reproductive-aged women and girls who participated in the National Free Pre-pregnancy Checkups in 2010-2012 and subsequently had a live birth before October 2013.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Incidence rates of PTB in reproductive-aged women and girls across preconception BP levels.

RESULT(S)

Preterm births were defined as babies born alive at 28 to 37 weeks of pregnancy. Compared with the participants with a systolic BP of <120 mm Hg, the multivariable-adjusted odds ratio (OR) for PTB was 0.99 (95% confidence interval [CI]: 0.95-1.03]), 1.21 (95% CI: 1.11-1.32), 1.47 (95% CI: 1.22-1.77), 1.80 (95% CI: 1.25-2.59), and 1.81 (95% CI: 1.20-2.73) for the participants with systolic BP of 120-129, 130-139, 140-149, 150-159, and ≥160 mm Hg, respectively. When the participants with normal BP were used as the reference, the adjusted OR for PTB was 1.04 (95% CI: 1.01-1.08), 1.38 (95% CI: 1.25-1.53), and 1.54 (95% CI: 1.21-1.97) for the participants with prehypertension, stage-1 hypertension, and stage-2 hypertension, respectively. In addition, isolated systolic and diastolic hypertension increased the risk of PTB by 55% and 30%, respectively.

CONCLUSION(S)

Our results indicated a strong linear and independent relationship between BP levels and the risk of PTB in Chinese reproductive-aged women and girls. Maternal hypertension before pregnancy can significantly increase the risk of PTB.