Time trends in the prevalence and epidemiological characteristics of neural tube defects in Liaoning Province, China, 2006-2015: A population-based study

Perinatal prevalence of birth defects in the Mainland of China, 2000-2021: a systematic review and meta-analysis

BACKGROUND

Although birth defects are of great concern globally, the latest national prevalence has not yet been quantified in China. We conducted a systematic review and meta-analysis to estimate the perinatal prevalence of birth defects in the Mainland of China between 2000 and 2021.

METHODS

We performed a systematic literature search of six databases for relevant articles published between January 1, 2000, and March 1, 2023. We included published studies that reported data on the perinatal prevalence of birth defects in the Mainland of China. The DerSimonian and Laird random-effects models were used to estimate the pooled prevalence and its 95% confidence interval (CI). We also conducted subgroup analyses and univariable meta-regressions to explore differences in prevalence by time period, geographic region, and other characteristics.

RESULTS

We included 254 studies reporting the perinatal prevalence of birth defects and 86 studies reporting only the prevalence of specific types of birth defects. Based on 254 studies covering 74,307,037 perinatal births and 985,115 cases with birth defects, the pooled perinatal prevalence of birth defects was 122.54 (95% CI 116.20-128.89) per 10,000 perinatal births in the Mainland of China during 2000-2021. Overall, the perinatal prevalence of birth defects increased from 95.60 (86.51-104.69) per 10,000 in 2000-2004 to 208.94 (175.67-242.22) per 10,000 in 2020-2021. There were also significant disparities among different geographical regions. Congenital heart defects (33.35 per 10,000), clefts of the lip and/or palate (13.52 per 10,000), polydactyly (12.82 per 10,000), neural tube defects (12.82 per 10,000), and inborn errors of metabolism (11.41 per 10,000) were the five most common types of birth defects. The perinatal prevalence among males was significantly higher than that among females (β = 2.44 × 10-3, P = 0.003); a higher perinatal prevalence of birth defects was observed among perinatal births whose mothers were ≥ 35 years (β = 4.34 × 10-3, P < 0.001).

CONCLUSION

Comprehensive and sustained efforts are needed to strengthen surveillance and detection of birth defects, improve prenatal and postnatal healthcare, and promote rehabilitation, especially in underdeveloped areas.

Secular trends and age-period-cohort effect on adverse perinatal outcomes in Hubei, China (2011-2019)

The increasing trend in the incidence of adverse perinatal outcomes is a public health concern globally as well as in China. However, the causes of the increasing trend are not well understood. The present tertiary-hospital-based retrospective study (2011-2019) aims to determine the secular trends and age-period-cohort effect on adverse perinatal outcomes in Hubei, China. The age-standardized incidence rates of adverse perinatal outcomes significantly decreased such as preterm births by 22% [AAPC - 3.4% (95% CI - 7.8, - 1.2)], low birth weight (LBW) by 28.5% [AAPC - 4.7% (95% CI - 6.0, - 3.3)], and fetal distress by 64.2% [AAPC - 14.0% (95% CI - 17.8, - 10.0)] during 2011-2019. Both extremes of maternal age groups (18-20 years and 42-44 years) had a higher risk ratio for adverse perinatal outcomes including preterm birth, perinatal mortality, LBW, low ponderal index (LPI), low Apgar score, and congenital defect compared to the reference age group (30-32 years). A higher risk ratio for perinatal mortality, intrauterine growth restriction (IUGR), and fetal distress and a lower risk ratio for preterm births and LBW were observed in the period 2017-2019. Both the young cohort (1997-1999) and the old cohort (1976-1969) had a higher risk ratio for preterm birth, perinatal mortality, macrosomia, and congenital defect compared to the reference cohort (1982-1984). In conclusion, some of the adverse perinatal outcomes incidence significantly decreased in the last 9 years in Hubei. However, extremes of maternal age groups and both young and old cohorts were associated with a higher risk of preterm birth, perinatal mortality, and congenital defect.

Study on the relationship between genetic polymorphism of reductive folic acid carrier and the risk of neural tube defects

BACKGROUND

To investigate the association of folate metabolism gene polymorphism with neural tube defects (NTDs) in Chinese population.

METHODS

The subjects were divided into two groups, 495 children with NTDs (NTD group) and 255 healthy children (control group).

RESULTS

The levels of folic acid, s-adenosine methionine (SAM), and Sam/s-adenosine homocysteine (SAH) in NTD group were lower than those in control group. There were significant differences in hey, SAH, and Sam levels between two groups, but there was no significant difference in folic acid content. High fever in early pregnancy, taking antiepileptic drugs, father's exposure to organic solvents, folic acid deficiency, and mother's diabetes were the important risk factors in NTDs. MTHFR 677C > T gene was a risk factor for NTD in children, while 1298A > C gene was a protective factor.

CONCLUSION

Folic acid metabolism markers were different in NTD children and their mothers, and the overall trend showed that folate, SAM, and SAM/SAH levels were decreased, while Hcy and SAH levels were increased; MTHFR 677C > T gene of SNPs was a risk factor for the occurrence of NTDs, and MTHFR 1298A > C gene was a protective factor, and the environmental risk factor had a synergistic effect on occurrence of NTDs.

Global prevalence of congenital anencephaly: a comprehensive systematic review and meta-analysis

Background

Anencephaly is a fatal congenital anomaly characterized by the absence of brain hemispheres and cranial arch. Timely preventive measures can be taken by knowing the exact prevalence of this common neural tube defect; thus, carried out through systematic review and meta-analysis, the present study was conducted to determine the worldwide prevalence, incidence and mortality of anencephaly.

Methods

Cochran’s seven-step instructions were used as the guideline. Having determined the research question and inclusion and exclusion criteria, we studied MagIran, SID, Science Direct, WoS, Web of Science, Medline (PubMed), Scopus, and Google Scholar databases. Moreover, the search strategy in each database included using all possible keyword combinations with the help of “AND” and “OR” operators with no time limit to 2021. The I² test was used to calculate study heterogeneity, and Begg and Mazumdar rank correlation tests were employed to assess the publication bias. Data were analyzed by Comprehensive Meta-Analysis software (Version 2).

Results

In this study, the statements of Preferred Reporting Items for Systematic Reviews and Meta-Analyzes (PRISMA) were used. In the first stage, 1141 articles were found, of which 330 duplicate studies were omitted. 371 articles were deleted based on the inclusion and exclusion criteria by reviewing the title and abstract of the study. 58 articles were removed by reviewing the full text of the article because it was not relevant to the research. 360 studies with a sample size of 207,639,132 people were considered for the meta-analysis. Overall estimate of the prevalence, incidence and attenuation of anencephaly worldwide were 5.1 per ten thousand births (95% confidence interval 4.7–5.5 per ten thousand births), 8.3 per ten thousand births (95% confidence interval 5.5–9.9 per ten thousand births), 5.5 per ten thousand births (95% confidence interval 1.8–15 per ten thousand births) respectively the highest of which according to the subgroup analysis, belonged to the Australian continent with 8.6 per ten thousand births (95% confidence interval 7.7–9.5 per ten thousand births).

Conclusion

The overall prevalence of anencephaly in the world is significant, indicating the urgent need for preventive and treating measures.

Anencephaly is a fatal congenital anomaly characterized by the absence of brain hemispheres and cranial arch. Cochran’s seven-step instructions were used as the guideline. Having determined the research question and inclusion and exclusion criteria, we studied MagIran, SID, Science Direct, WoS, Web of Science, Medline (PubMed), Scopus, and Google Scholar databases. Moreover, the search strategy in each database included using all possible keyword combinations with the help of “AND” and “OR” operators with no time limit to 2021. Out of 1141 initial articles found, and after excluding repetitive ones in various databases and those irrelevant to inclusion criteria, 360 studies with a sample size of 207,639,132 people were considered for the meta-analysis. Overall estimate of the prevalence, incidence and attenuation of anencephaly worldwide were 5.1 per ten thousand births (95% confidence interval 4.7–5.5 per ten thousand births), 8.3 per ten thousand births (95% confidence interval 5.5–9.9 per ten thousand births), 5.5 per ten thousand births (95% confidence interval 1.8–15 per ten thousand births) respectively the highest of which according to the subgroup analysis, belonged to the Australian continent with 8.6 per ten thousand births (95% confidence interval 7.7–9.5 per ten thousand births). The overall prevalence of anencephaly in the world is significant, indicating the urgent need for preventive and treating measures.

Sacral Spina Bifida Occulta: A Frequency Analysis of Secular Change

Substantial relaxation of natural selection beginning around 1900 changed the mutation/selec­tion balance of modern genetic material, producing an increase in variable anatomical structures. While multiple structures have been affected, the temporal increase in variations of the sacrum, specifically, ‘Sa­cral Spina Bifida Occulta,’ have been reliably demonstrated on a localised scale. Calculation of largescale frequency has been hindered by the localised nature of these publications, the morphological variability of this variation, and potential pathological associations, which have produced divergent classifications, and conflicting reported rates of occurrence. A systematic review of the reported literature was conducted to provide an objective analysis of Sacral Spina Bifida Occulta frequency from 2500 BCE to the present. This review was designed to compensate for observed inconsistencies in reporting and to ascertain, for the first time, the temporal trajectory of this secular trend. A systematic review of Sacral Spina Bifida Occulta lit­erature was conducted through the strict use of clinical meta-analysis criteria. Publications were retrieved from four databases: PubMed, Embase, the Adelaide University Library database, and Google Scholar. Data were separated into three historical groups, (1 = <1900, 2 = 1900 to 1980 and 3 = >1980), and frequency outcomes compared, to determine temporal rates of occurrence. A total of 39/409 publications were included in the final analysis, representing data for 16,167 sacra, spanning a period of 4,500 years. Statistically significant results were obtained, with total open S1 frequen­cy increasing from 2.34%, (79 to 1900CE), to 4.80%, (1900 to 1980CE) and to 5.43% (>1980CE). These increases were significant at p<0.0001, with Chi-squared analysis. A clear secular increase in the global frequency of Sacral Spina Bifida Occulta has been demonstrated from 1900 to the present. This research provides a novel and adaptable framework for the future assessment of variation distribution, with impor­tant implications for the fields of biological anthropology and bioarchaeology.

Maternal Exposure to Sulfur Dioxide and Risk of Omphalocele in Liaoning Province, China: A Population-Based Case-Control Study

Evidence of the association between maternal sulfur dioxide (SO₂) exposure and the risk of omphalocele is limited and equivocal. We aimed to assess the aforementioned topic during the first trimester of pregnancy. A population-based case-control study was carried out in infants consisting of 292 cases of omphalocele and 7,950 healthy infant controls. Exposure to SO₂, particulate matter with aerodynamic diameters ≤ 10 μm, and nitrogen dioxide was assessed by averaging the concentration from all stations in the mother's residential city. SO₂ exposure was categorized into three groups, with the lowest tertile defined as the reference category. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using multivariable logistic regression models. Higher SO₂ exposure during the first trimester was significantly associated with omphalocele risk [per standard deviation (42 ug/m³) increment: OR = 1.39, 95% CI = 1.22–1.65]. When focusing on shorter exposure windows, similar positive associations were observed for SO₂ exposure in the first and third months of pregnancy. In addition, compared with the lowest tertile, high SO₂ exposure in the second month of pregnancy increased the risk of omphalocele (OR = 2.80, 95% CI = 1.61–4.97). Maternal exposure to SO₂ during the first trimester may increase the risk of omphalocele in offspring.

Association between maternal exposure to PM10 and risk of anorectal atresia/stenosis in offspring: a population-based case-control study in Liaoning Province, China

The potential association between maternal exposure to PM₁₀ ranging from 3 months prior to conception to the end of the early trimester and the risk of anorectal atresia/stenosis in offspring has not been established. Thus, we determined the association between maternal exposure to PM₁₀ and risk of anorectal atresia/stenosis in offspring in this study. We recruited 713 patients including 480 male and 233 female with anorectal atresia/stenosis and 7950 randomly selected healthy offspring from the Maternal and Child Health Certificate Registry of Liaoning Province and delivered between 1 January 2010 and 31 December 2015. Monthly PM₁₀ concentrations were retrieved from the Environment Protection Bureau of each city in Liaoning Province. We established a multivariable logistic regression model to calculate the adjusted odds ratios (ORs) and 95% confidence intervals (CIs). Maternal exposure to PM₁₀ was associated with an increased risk for anorectal atresia/stenosis in offspring during the 3 months prior to conception (per 10 μg/m³ increment: OR = 1.15, 95% CI = 1.03-1.20; per SD [27 μg/m³] increment: OR = 1.33, 95% CI = 1.09-1.63) and the first trimester (per 10 μg/m³ increment: OR = 1.08, 95% CI = 1.00-1.17; per SD [28 μg/m³] increment: OR = 1.26, 95% CI = 1.01-1.57). Evaluation of the association with a shorter exposure window (1 month) revealed a positive association between anorectal atresia/stenosis and PM₁₀ from the 3rd month prior to pregnancy to each month of the 1st trimester. Maternal exposure to PM₁₀ 3 months prior to conception and during the 1st trimester was associated with an increased risk of anorectal atresia/stenosis in the offspring. Future perspective cohort studies are needed to confirm our findings.

Maternal exposure to ambient SO2 and risk of polydactyly and syndactyly: a population-based case-control study in Liaoning Province, China

Evidence links exposure to maternal sulfur dioxide (SO₂) and the risk of limb defects have been inconsistent. To investigate associations between SO₂ exposure during preconception and the first trimester and risks of polydactyly and syndactyly. The study population was acquired from the Maternal and Child Health Certificate Registry of Liaoning Province between 2010 to 2015, and consisted of 2605 polydactyly, 595 syndactyly cases, and 7950 controls. Ambient air pollutants levels were retrieved from air quality monitoring stations. We used multivariable logistic regression model to assess the adjusted odds ratios (ORs) and 95% confidence intervals (CIs). We found that exposure to increased SO₂ concentrations was associated with polydactyly during both the 3 months preconception (OR_{Q4 vs. Q1} = 3.76; 95% CI 2.61, 5.42; per 10 μg/m³ increment: OR = 1.07; 95% CI 1.04, 1.10) and the first trimester (OR_{Q4 vs. Q1} = 2.03; 95% CI 1.41, 2.92; per 10 μg/m³ increment: OR = 1.07; 95% CI 1.03, 1.11). However, we only observed increased risk for syndactyly in the analysis of high vs. low quartiles (three months preconception: OR_{Q4 vs. Q1} = 3.72; 95% CI 2.05, 6.75; first trimester: OR_{Q4 vs. Q1} = 1.98; 95% CI 1.11, 3.51). Most results of analyses based on single-month exposure window generally showed similar positive associations. Additionally, these findings were broadly consistent across subgroups and sensitivity analyses. Maternal SO₂ exposure increase the risk of polydactyly and syndactyly.

Maternal exposure to ambient levels of sulfur dioxide and risk of neural tube defects in 14 cities in Liaoning province, China: a population-based case-control study

Epidemiological studies on the association of sulfur dioxide (SO₂) with neural tube defects (NTDs) are lacking. The purpose of this study was to assess the aforementioned association through a population-based case-control study. This study involved 1457 NTDs cases and 7950 randomly selected healthy infants born in 14 cities in Liaoning province between 2010 and 2015. Ambient SO₂ levels were acquired from 75 monitoring stations. The exposure assessment was based on the mean concentration of all stations in mother's residential city. We used logistic regression models to assess the associations. In multivariable models adjusted for the confounding variables selected based on the 10 percent change-in-estimate method, we found that maternal SO₂ exposure was positively associated with an increased risk of NTDs during the first month after conception (per 10 μg/m³ increase: adjusted odds ratio [aOR] = 1.02, 95% confidence interval [CI]: 1.00-1.04; highest versus lowest quartile: aOR = 2.55, 95% CI: 1.97-3.31) and the second month after conception (per 10 μg/m³ increase: aOR = 1.02, 95% CI: 1.00-1.04; highest versus lowest quartile: aOR=2.31, 95% CI: 1.77-3.00). For other exposure windows, positive associations also emerged in high- versus low-exposure analyses, except for the third month before conception; however, we could not further confirm significant findings from the continuous exposure analyses. Our study provides a new evidence that SO₂ exposure may increase the risk of NTDs.

Maternal exposure to ambient particulate matter 10 μm or less in diameter before and after pregnancy, and anencephaly risk: A population-based case-control study in China

BACKGROUND

There is no epidemiological evidence on the effects of maternal exposure to ambient particulate matter 10 μm or less in diameter (PM₁₀) and anencephaly risk in offspring.

METHODS

We conducted a population-based case-control study in Liaoning Province, China. The case group consisted of 663 cases with anencephaly and the control group consisted of 7950 healthy infants from the Maternal and Child Health Certificate Registry of Liaoning Province that were born between 2010 and 2015. Daily PM₁₀ concentrations were obtained from 77 monitoring stations located within the study area. A multivariable logistic regression model was established to calculate the adjusted odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Maternal PM₁₀ exposure was significantly associated with an increased risk of anencephaly at three months before conception (highest versus lowest tertile: OR = 1.74, 95% CI: 1.29-2.34; per 10 μg/m³ increment: OR = 1.13, 95% CI: 1.06-1.20) and three months after conception (highest versus lowest tertile: OR = 1.93, 95% CI: 1.44-2.60; per 10 μg/m³ increment: OR = 1.01, 95% CI: 0.95-1.08). The evaluation of shorter exposure windows revealed similar associations for PM₁₀ exposure from the third month before pregnancy to the third month after pregnancy.

CONCLUSIONS

Maternal PM₁₀ exposure is positively associated with anencephaly risk during the critical period of neural system development.

Association between maternal exposure to PM10 and polydactyly and syndactyly: A population-based case-control study in Liaoning province, China

BACKGROUND

The number of studies on air pollution with birth defects as the primary outcome has increased dramatically over the past two decades, but the potential role of specific air pollutants in congenital limb anomalies remains unclear.

OBJECTIVES

To evaluate associations between preconception and first-trimester PM₁₀ exposure and polydactyly and syndactyly in a population-based case-control study.

METHODS

Polydactyly cases (n = 2605), syndactyly cases (n = 595), and controls without any birth defects (n = 7950) born between 2010 and 2015 were selected from the Maternal and Child Health Certificate Registry of Liaoning Province. The monthly mean PM₁₀ concentrations were obtained from 75 air monitoring stations, and the exposure assessment was based on the mean concentration of all stations in mother's residential city. A multivariable logistic regression model was constructed to calculate adjusted odds ratios (aORs) and 95% confidence intervals (CIs).

RESULTS

PM₁₀ exposure was positively associated with the risks of polydactyly (preconception: aOR_{T3 vs. T1} = 1.95, 95% CI 1.56-2.45, aOR = 1.06, 95% CI 1.01-1.10 [per 10-μg/m³ increment]; first-trimester: aOR_{T3 vs. T1} = 2.51, 95% CI 2.00-3.15) and syndactyly (preconception: aOR_{T3 vs. T1} = 2.86, 95% CI 1.98-4.13, aOR = 1.11, 95% CI 1.03-1.20 [per 10-μg/m³ increment]; first-trimester: aOR_{T3 vs. T1} = 3.10, 95% CI 2.11-4.56). Analyses based on single month exposure windows basically showed similar positive associations. Additionally, these findings were robust in sensitivity analyses and broadly consistent across subgroups.

CONCLUSION

Our study suggest that preconception and first-trimester PM₁₀ exposures are related to increased risks of polydactyly and syndactyly.

Epidemiology and determinant factors of neural tube defect: Narrative review

Background

The epidemiology of neural tube defect (NTD) is face ignorance from the global community. However, the problem is complex and it is a cause for child mortality and morbidity. We provide the latest insights with respect to determinant factors of NTD.

Methods

Google Scholar and PubMed were systematically searched to identify potential research articles concerning the epidemiology and its determinant factors of NTD.

Results

The epidemiology of Neural tube defects increased in some countries. The epidemiology and determinant factors were varies across countries,geographical regions and socioeconomic status of the populations. In general, the determinant factors of NTD were summarized as behavioral, nutrition-related, environmental, medical illness, and health service-related factors.

Conclusion

Birth defect is fatal which affects the new generation; specifically, NTD is the problem of middle- and low-income countries. It is a direct cause for neonatal and perinatal mortality rate globally. Even if little factors identified, yet conducting experimental and clinical trial researches are a better approach to slow down the progress.

Changes in maternal age and prevalence of congenital anomalies during the enactment of China's universal two-child policy (2013-2017) in Zhejiang Province, China: An observational study

BACKGROUND

China implemented a partial two-child policy (2013) followed by a universal two-child policy (2015), replacing the former one-child policy mandated by the government. The changes affect many aspects of China's population as well as maternal and infant health, but their potential impact on birth defects (BDs) remains unknown. In this study, we investigated the associations of these policy changes with BDs in Zhejiang Province, China.

METHODS AND FINDINGS

We used data from the BD surveillance system in Zhejiang Province, China, which covers 90 hospitals in 30 urban districts and rural counties, capturing one-third of the total births in this province. To fully consider the time interval between conception and delivery, we defined the one-child policy period as data from 2013 (births from October 2012 to September 2013), the partial two-child policy period as data from 2015 (births from October 2014 to September 2015), and the universal two-child policy period as data from 2017 (births from October 2016 to September 2017). Data from 2009 and 2011 were also used to show the changes in the proportion of births to women with advanced maternal age (35 years and older) prior to the policy changes. Main outcome measures were changes in the proportion of mothers with advanced maternal age, prevalence of BDs, rankings of BD subtypes by prevalence, prenatal diagnosis rate, and live birth rate of BDs over time. A total of 1,260,684 births (including live births, early fetal losses, stillbirths, and early neonatal deaths) were included in the analyses. Of these, 644,973 (51.16%) births were to women from urban areas, and 615,711 (48.84%) births were to women from rural areas. In total, 135,543 (10.75%) births were to women with advanced maternal age. The proportion increased by 85.68%, from 8.52% in 2013 to 15.82% in 2017. However, it had remained stable prior to policy changes. Overall, 23,095 BDs were identified over the policy changes (2013-2017). The prevalence of BDs during 2013, 2015, and 2017 was 245.95, 264.86, and 304.36 per 10,000 births, respectively. Trisomy 21 and other chromosomal defects increased in both risk and ranking from 2013 to 2017 (crude odds ratio [95% confidence interval] 2.13 [1.75-2.60], from ranking 10th to 5th, and 3.63 [2.84-4.69], from ranking 16th to 6th, respectively). The prenatal diagnosis rate increased by 3.63 (2.2-5.1) percentage points (P < 0.001), from 31.10% to 34.72%, and identification of BDs occurred 1.88 (1.81-1.95) weeks earlier (P < 0.001). The live birth rate for infants with BDs born before 28 gestational weeks increased from 1.29% to 11.45%. The major limitations of this observational study include an inability to establish causality and the possible existence of unknown confounding factors, some of which could contribute to BDs.

CONCLUSIONS

In this study, we observed significant increases in maternal age and the prevalence of total and age-related anomalies following China's new two-child policy. Increases in live birth rate for infants with BDs born before 28 gestational weeks suggest that healthcare for very preterm births with BDs may be warranted in the future, as well as updating the definition of perinatal period.

Association between maternal exposure to ambient PM10 and neural tube defects: A case-control study in Liaoning Province, China

BACKGROUND

The potential association between maternal exposure to ambient PM₁₀ and offspring neural tube defects (NTDs) is a contentious issue. This study aims to evaluate the aforementioned association at a provincial level in China.

METHODS

A total of 2736 cases and 7950 randomly selected healthy infants included in the Maternal and Child Health Certificate Registry of Liaoning Province and delivered between 2010 and 2015 were recruited. Daily PM₁₀ concentrations were obtained from all available monitoring stations located within the study area. A multivariable logistic regression model was established to calculate the adjusted odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

PM₁₀ exposure was significantly associated with the risk of NTDs during the three months preconception (per 10 μg/m³ increment: OR = 1.10, 95% CI 1.07-1.14; per standard deviation [27 μg/m³] increment: OR = 1.29, 95% CI 1.18-1.41; highest tertile: OR = 1.61, 95% CI 1.37-1.91) and the first trimester (highest tertile: OR = 1.57, 95% CI: 1.31-1.87). When focusing on shorter exposure windows, similar associations were observed for PM₁₀ exposure from the third month before pregnancy to the third month after pregnancy. Sensitivity analyses using propensity score matching yielded consistent findings.

CONCLUSIONS

Maternal exposure to PM₁₀ is positively associated with NTDs during the critical period of fetal neural tube development. However, due to the limitation of the exposure assessment as well as potential residual confounding, further research is warranted to confirm our findings.

Assessment of the development of assisted reproductive technology in Liaoning province of China, from 2012 to 2016

BACKGROUND

The development of assisted reproduction techniques (ART) has resulted in rapid advances in the treatment of infertility. However, a systematic assessment of ART and its processes and outcomes in China has never been carried out. The goal of this study was to assess the features of ART status from 2012 to 2016 in clinics and in vitro fertilization (IVF) laboratories in Liaoning, the largest IVF province in the northeast of China.

METHODS

Data from Jan 1, 2012 to Dec 31, 2016 was retrieved from the assisted reproductive certificate registry of Liaoning province. We extracted data from: i) fresh and thawed cycles; ii) donor sperm and donor egg cycles; iii) intrauterine insemination with husband semen and donor semen (AIH and AID).

RESULTS

We showed that: (i) there has been a significant increase in the number of IVF fresh and thawed cycles, and the proportion of cases of primary infertility and secondary infertility has decreased and increased, respectively; (ii) standard long GnRH agonist was the major ovarian stimulation protocol. During the observation period, increasing trends in the use of GnRH antagonists, mild stimulation, and natural cycles were observed; (iii) significant differences in the number of cycles, number of retrieved oocytes, fertilization rates, implantation rates, and sex ratio were noticed between conventional IVF and intracytoplasmic sperm injection; (iv) significant differences in age at treatment for infertility, number of cycles, and ectopic pregnancy rates were noticed between donor sperm cycles and donor egg cycles; (v) significant differences in number of thawed cycles, number of thawed embryos, embryo recovery rates, implantation rates, and clinical pregnancy rates were noticed between day 3 and day 5 embryos; (vi) significant differences in age at treatment for infertility, number of cycles, clinical pregnancy rates, ectopic pregnancy rates, and live birth ratio were noticed between AIH and AID.

CONCLUSIONS

ART in Liaoning province has undergone substantial development from 2012 to 2016 in clinics and IVF laboratories. This presentation of detailed ART data will provide researchers, policy makers, and potential ART users a rich source of information about IVF characteristics in the northeast of China.

Prevalence and trend of isolated and complicated congenital hydrocephalus and preventive effect of folic acid in northern China, 2005-2015

Congenital hydrocephalus (CH) was a major birth defect of the central nervous system besides neural tube defects (NTDs). Few studies have focused on both the prevalence and trend of isolated and complicated CH in China. Data were drawn from a population-based birth defects surveillance program in five rural counties in northern China from 2005 to 2015. All livebirths and pregnancy terminations at any gestational age affected with CH were recorded. The prevalence and trend of isolated and complicated CH were examined. During the 11-year period, a total of 176,223 births and 357 CH cases were recorded, resulting in a prevalence rate of 20.3 CH cases per 10,000 births. Of the CH cases, 146 were isolated CH, resulting in a prevalence rate of 8.3 per 10,000 births. The pre-perinatal prevalence (<28 gestational weeks) was higher than the perinatal prevalence for both isolated and total CH. The prevalence rates of total and isolated CH showed a similar downward trend during the 11-year period. This downward trend was statistically significant after 2009 (p < 0.05), when a massive folic acid supplementation program was introduced. Although it decreased over time, the prevalence of CH remains high in this population which has a high prevalence of neural tube defects.

The recurrence risk of neural tube defects (NTDs) in a population with high prevalence of NTDs in northern China

Background

Although a number of studies have reported the recurrence risk of NTDs in developed countries, there is little data on the rate of recurrence of NTDs in northern China, a region of high prevalence of NTDs.

Methods

Based on the population-based birth defects surveillance system of five counties, we identified women who had an NTD affected pregnancy from 2004-2015 and a retrospective survey was conducted. The rate of recurrence of NTDs was calculated by the number of recurrent NTDs divided by the first NTDs. Maternal age, body mass index (BMI), gestational weeks, education, and occupation were collected. Information on folic acid (FA) supplements, time and dosage were also recorded.

Results

Among 851 women who had a previous NTD-affected pregnancy, there were 578 subsequent pregnancies, with 10 recurrent NTDs, a 1.7% recurrence rate. The recurrence rate was 1.5% and 2.6% for those taking FA supplements and without FA supplementation respectively. Women with recurrent NTDs had higher BMI before pregnancy compared to those who had a second pregnancy without NTDs. Among the recurrent NTDs, the majority were spina bifida.

Conclusions

The recurrence rate of NTDs was approximately five times higher than the overall prevalence in the same region of northern China. Risk of recurrence appeared lower among women who took FA supplements. These findings are consistent with the reduction in NTD frequency in the population since introduction of the nationwide FA supplement program. Data on recurrence rates in northern China will inform power calculations for future intervention studies.