In March 2021, researchers at the University of Washington published in Lancet, the top international medical journal[1], that the global population is expected to peak at 9.73 billion in 2064 and fall to 8.79 billion by 2100. By 2024, Chinese are expected to peak at about 1.43 billion, up from 1.41 billion in 2017, followed by a 49% decline in 2100 to around 732 million, making it the world's third most populous country.
Asia, Central and Eastern Europe will be the region with the fastest rate of population shrinkage, and the population of 23 countries and regions, including China, Japan, South Korea and Italy, will be reduced to half of the original. Reference projections for the five largest countries in 2100 are India (1.09 billion), Nigeria (791 million), China (732 million), the United States (336 million) and Pakistan (248 million). The findings also show that by 2100, the age structure in many parts of the world is changing, with 2.37 billion individuals over the age of 65 and 1.70 billion individuals under the age of 20.
As early as December 2020, the news that "the total fertility rate broke the warning line" was on Weibo's hot search and triggered heated discussions. Weibo mentioned that Li Jiheng, minister of civil affairs, recently wrote an article saying that the mainland's school-age population has a low willingness to have children, the mainland's population development has entered a critical turning point, and the number of newborn populations has declined for several consecutive years. Prior to this, Ren Zeping of Evergrande Research Institute had said that it was recommended to let go of the three children as soon as possible during the "14th Five-Year Plan" period, gradually promote and observe the effect, and the successive statements of the two authoritative figures could not help but make people wonder whether the "three children" era was coming?
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On May 31, 2021, the Political Bureau of the CPC Central Committee held a meeting to review the Decision on Optimizing The Birth Policy to Promote the Long-term Balanced Development of the Population and pointed out that in order to further optimize the birth policy, the policy of three children for a couple and supporting measures were implemented. On July 20, 2021, the Decision of the CPC Central Committee and the State Council on Optimizing The Birth Policy to Promote the Long-term Balanced Development of the Population was announced, and on July 21, the Office of the National Medical Security Bureau issued the Notice on Supporting The Birth Insurance Work of the Three-Child Policy. On August 20, 2021, the Standing Committee of the National People's Congress voted to pass a decision on amending the Population and Family Planning Law, which stipulates that the state advocates marriage and childbearing of appropriate age and eugenics, and a couple can have three children.
In fact, the liberalization of the three-child policy has many benefits, such as allowing only children to be accompanied and reducing the aging of the population.
But how many people are willing to have three children? A few days ago, the Xi'an survey team of the National Bureau of Statistics selected 100 young people of childbearing age in the city to carry out a special survey, and the survey showed that 2% of young people of childbearing age chose to be "Dink" and did not consider having children; 67% of young people of childbearing age were only willing to have one child; 23% of young people of childbearing age were willing to accept "two children"; only 8% of young people of childbearing age could accept "three children". The survey also shows that in the 20-25-25-year-old, 25-30-year-old, 30-35-year-old, 35-40-year-old age age is willing to have a second child, "three-child" young people of childbearing age accounted for 10%, 12.8%, 14.3% and 15.4% respectively, according to which the older the age of young people of childbearing age, the stronger the fertility intention of "two children" and "three children", these families have a more stable economic foundation, and can afford the cost of having children, so the willingness to have children is relatively high.
Image source: National Bureau of Statistics, Essence Securities Research Center
So what is the impact of a woman's pregnancy and childbirth on her physical health?
In a study published in the journal Nature Communications[2], scientists from institutions such as the Cold Spring Harbor Laboratory in the United States found that pregnancy may reduce the risk of breast cancer through epigenetic reprogramming, and pregnancy reprogramming chromatin enhancers in mouse MECs and affecting the transcriptional output of oncogenic transcription factors (cMYC).
Previously, researchers at Columbia University and other institutions found that the number and age of pregnancies affect a woman's risk of breast cancer. In the article, the researchers found that women with multiple pregnancies and breastfeeding had a lower risk of breast cancer. However, in a study published in the international journal Annals of Internal Medicine[4], scientists from the University of North Carolina's Linearberger Comprehensive Cancer Center conducted a large-scale analysis and found that young women who have recently given birth to children are at higher risk than women of the same age who have not had children or develop breast cancer, and that the association between fertility and women's risk of breast cancer may need further research to be clarified.
In a study published in the journal European Society of Cardiology[5], scientists from the Tongji School of Medicine of Huazhong University of Science and Technology found that women who had never had children had a relatively 14% higher risk of heart disease and stroke than women who had never had children. Researchers say there is a significant correlation between pregnancy and the risk of cardiovascular disease, which adds up with an increase in the number of pregnancies; there is evidence that there is a "J-shaped" relationship between the two.
As early as 2018, scientists from Northwestern University in the United States found through research [6] that multiple pregnancies can make women's cells aging faster. In the paper, the researchers looked at two markers of cell senescence: telomere length and epigenetic age. The findings suggest that each pregnancy experiences a woman's cells to age 0.5-2 years, and that women who are pregnant are younger than expected.
We often hear people say that it is true that a fool of three years in pregnancy is not true? In a study published in the Medical Journal of Australia[7], scientists from Deakin University found that pregnant women performed poorly on memory tests and executive function tests compared to non-pregnant women, and these differences were most pronounced during the third trimester. The researchers also found that the results of the same women tested at different times showed that these functional reductions began to appear in the first trimester of pregnancy and then stabilized in the second trimester until giving birth. The researchers believe that pregnancy stupidity is actually an important adaptive phenomenon, perhaps by changing women's brains to make them more suitable for raising children, and more importantly, the study also found that the reduced hippocampal gray matter in women's brains will recover two years after the birth of the child, which means that cognitive decline is not permanent.
It can be seen that pregnancy will affect the health of women in many aspects, with the three-child policy and supporting measures continue to be promulgated, will you consider having three children?
bibliography:
【1】Stein Emil Vollset，Emily Goren，Chun-Wei Yuan， et al. Fertility， mortality， migration， and population scenarios for 195 countries and territories from 2017 to 2100：a forecasting analysis for the Global Burden of Disease Study， Lancet. 2020 Oct 17；396(10258)：1285-1306. doi：10.1016/S0140-6736(20)30677-2. Epub 2020 Jul 14.
【3】Mary Beth Terry，Yuyan Liao，Karin Kast， et al. The Influence of Number and Timing of Pregnancies on Breast Cancer Risk for Women With BRCA1 or BRCA2 Mutations， JNCI Cancer Spectrum (2018).doi：10.1093/jncics/pky078
【4】Hazel B. Nichols et al. Breast Cancer Risk After Recent Childbirth：A Pooled Analysis of 15 Prospective Studies. Annals of Internal Medicine， 2018 DOI：10.7326/M18-1323
【5】Wenzhen Li， Wenyu Ruan， Zuxun Lu，et al. Parity and risk of maternal cardiovascular disease：A dose–response meta-analysis of cohort studies， European Society of Cardiology (2018)，December 19， 2018， doi：10.1177/2047487318818265
【7】Sasha J Davies，Jarrad Ag Lum，Helen Skouteris， et al. Cognitive impairment during pregnancy：a meta-analysis， MJA，2018 Jan 15；208(1)：35-40. doi：10.5694/mja17.00131.