Introduction Macrosomia has short-term and long-term adverse health effects and is thus an important public health concern. Recent decades have witnessed increasing incidence of macrosomia in many countries. Methods The present study used a large population-based birth cohort study to depict incidence of macrosomia among live births in rural areas of Henan Province of China from 2013 to 2017. Results Among the 1,262,916 births, 82,353 were cases of macrosomia. The overall incidence of all types of macrosomia, of macrosomia with birth weight <4,500 g, and of macrosomia with birth weight ≥4,500 g were 6.52%, 5.30%, and 1.22%, respectively. From 2013 to 2017, the incidence of macrosomia decreased by 31.3% from 7.96% in 2013 to 5.47% in 2017 ($ \chi _{trend}^2 $=946.96, $ {P}_{trend} $<0.001). Male infants and infants ≥42 gestational weeks had significantly higher incidence of macrosomia than that of female infants and infants <42 gestational weeks (P<0.001). Conclusion Gestational weight control through nutrition management and physical activities during pregnancy are needed to reduce incidence of macrosomia.

Background: Maternal vitamin D deficiency might generate adverse reproductive outcomes, and socio-economic inequalities in micronutrient-related diseases have often been found. This study aimed to explore the interactive effects of maternal vitamin D status and socio-economic status (SES) on risk of spontaneous abortion. Methods: A population-based case–control study was conducted including 293 women with spontaneous abortion and 498 control women in December 2009 and January, 2010 in Henan Province, China. Information on pregnancy outcomes, maternal demographic, lifestyle and exposure factors and blood samples were collected at the same time. Vitamin D deficiency was defined as 25(OH)D < 20 ng/mL. SES index was constructed with principal component analysis by aggregating women’s and their husbands’ education level and occupation, and household income and expenditure. Interactive effects were assessed on a multiplicative scale with ratio of the odds ratio (ROR). Results: Compared to those with high SES and vitamin D sufficiency, women with vitamin D deficiency and low SES index had an increased risk of spontaneous abortion (aOR: 1.99; 95% CI: 1.23–3.23). The ROR was 2.06 (95% CI: 1.04–4.10), indicating a significant positive multiplicative interaction. Conclusions: Maternal low SES may strengthen the effect of vitamin D deficiency exposure on spontaneous abortion risk in this Chinese population.

The spatial patterns of adverse pregnancy outcomes (APOs) are complex, vary by place, and remain not entirely clear. This study investigated spatiotemporal patterns of APOs in rural areas of Henan, China. We used data from 1,315,327 singleton pregnancies during 2013–2016 in rural areas of Henan, China, from the National Free Pre-pregnancy Checkup Program (NFPCP). A spatiotemporal analysis of APOs was conducted based on the time of conception and current address. Results of seasonality decomposed showed a slight decline in the incidence rate of APOs (12.93% to 11.27% in the compound trend) among the participants from 2013 to 2016 and also variation in annual periodicity (peaking in autumn at 12.66% and hitting bottom in spring at 11.16%). Spatial clusters of APOs were concentrated in an intersection band of northwestern to southeastern Henan Province (with a relative risk ratio ranging from 3.66 to 1.20), the northwestern and northern portion for temporal variation (having a trend in the cluster ranged from −6.25% to 83.93). This study provides an overall picture of APOs that presented downward trends over time, seasonal fluctuation, and clustered patterns across space and over time in Henan Province—the most populated province in China. The findings of this study warrant future studies to investigate underlying influential factors of spatial variation of APOs.