Analysis of unintended pregnancy and influencing factors among married women in China

Unintended pregnancy often ends with induced abortion, an outcome that affects a woman’s physical and mental health and consumes social resources. A national fertility survey conducted by the former National Health and Family Planning Commission in 2017, gathered data on pregnancies among married women aged 15–49 to analyze the changing circumstances of such pregnancies and the factors that influence their occurrence. The analysis found that the incidence of unintended pregnancies among married women in China was 42.4‰ in 2017, and that such pregnancies accounted for 22.9% of all pregnancies in China for the years 2010–2017. Of all abortions, 91.9% were used to terminate unintended pregnancies, and of unintended pregnancies, 67.1% ended with induced abortions. The incidence of unintended pregnancy and that of induced abortion to terminate the unintended pregnancy were higher among women living in an urban rather than a rural area, having previously given birth to a boy, having a large number of children, being at the older end of their childbearing years, or having a shorter interpregnancy interval. Only 37.3% of women chose long-term contraceptive methods after an induced abortion caused by an unintended pregnancy; their sense of self-protection was not strong. It is necessary to strengthen education and advocacy, enhance women's awareness of the protection contraceptives offer, and improve the quality of and access to contraceptive services to reduce the incidence of unintended pregnancy, and reduce the incidence of induced abortion to terminate unintended pregnancy.


Introduction
Conceptually, unintended pregnancy is the opposite of intended pregnancy, and includes within its scope pregnancies occurring at inappropriate times and unwanted pregnancies (Logan et al., 2007;Santelli et al., 2003). According to UNFPA's State of World Population 2022, nearly half of all pregnancies worldwide are unintended pregnancies, with an average of 121 million unintended pregnancies annually. More than 60% of these unintended pregnancies are terminated by induced abortion. More than 8.5 million abortions have been performed in China every year since 2014, and most of these have terminated unintended pregnancies. Unintended pregnancy results in a huge waste of resources and has long-term negative effects on a country and its society (Sonfield et al., 2011(Sonfield et al., , 2013Trussell, 2007;Yazdkhasti et al., 2015). Induced abortion caused by unintended pregnancy has a negative impact on some women's physical and mental health (Zhang et al., 2021). Abortion-related mortality and morbidity is higher in region where the majority of abortions are classified as unsafe (Labandera et al., 2016). The Healthy China 2030 plan clearly states that reducing the incidence of unintended pregnancies and sexually-transmitted diseases are important parts of building a healthy China and promoting national modernization outline. 1 The main objectives of the Outline for Women's Development in China (2021China ( -2030 are to popularize the knowledge women need to give birth to healthy babies, to promote healthy pregnancy and reduce unintended pregnancies, and to implement basic contraceptive services and improve service accessibility as a part of strategies for women's health designed to prevent unintended pregnancies and reduce the number of abortions for non-medical needs. The purpose of this paper is to discuss unintended pregnancy, induced abortion and the factors influencing these phenomena, and put forward countermeasures and suggestions.

Definitions
Indicators used to estimate the level of unintended pregnancies include the incidence of unintended pregnancies and the proportion of total pregnancies that are unintended. The incidence of unintended pregnancies represents the average number of unintended pregnancies per 1000 women of childbearing age over a period of time. The proportion of unintended pregnancies represents the percentage of unintended pregnancies per 100 pregnancies over a period of time.

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Analysis of unintended pregnancy and influencing factors…

Changing trend of unintended pregnancy
As a result of the widespread use of contraceptives and changes in fertility patterns worldwide in recent decades, the overall trend shows that the incidence of unintended pregnancy has experienced a significant decline, while the proportion of unintended pregnancy has not changed much (Sedgh et al., 2014). Based on existing data, it is estimated that the global incidence of unintended pregnancy decreased from 69‰ in 1995 to 57‰ in 2008 and 53‰ in 2012, while the proportion of total pregnancy that was unintended decreased from 43% in 1995to 42% in 2008and 40% in 2012(Alan Guttmacher Institute, AGI, 1999Sedgh et al., 2014;Singh et al., 2010). Another estimate based on fertility data from 105 countries shows that the global incidence of unintended pregnancy decreased from 74‰ in 1990-1994 to 62‰ in 2010-2014, while the proportion of unintended pregnancy remained virtually unchanged over the past 2 decades, accounting for about 44% of all pregnancies (Bearak et al., 2018).

Regional factors
Globally, there are still significant regional differences in the level of unintended pregnancy, especially levels in developing/low-and middle-income countries, which are still significantly higher than those in developed/high-income countries (Bearak et al., 2018(Bearak et al., , 2020Gipson et al., 2008;Singh et al., 2010). It is estimated that between 2015 and 2019, there were approximately 35 unintended pregnancies per 1000 women of childbearing age in Europe and North America, compared with approximately 64 in Central and South Asia and 91 in the sub-Saharan region (Bearak et al., 2020(Bearak et al., , 2022. According to another study, the level of unintended pregnancy in developed countries decreased by about 30% in the 2 decades between 1990-1994 and 2010-2014, while it decreased by about 16% in developing regions (Bearak et al., 2018). Although the level of unintended pregnancy is declining in most regions, the incidence of unintended pregnancy in developing countries is still higher than that in developed countries, and the rate of decline is lower than that in developed countries.

Group factors
A fact that cannot be ignored is the difference in the level of unintended pregnancy between different demographic and economic groups. In the United States, for example, the incidence of unintended pregnancy is higher among women aged 18-24, low-income women, unmarried cohabiting women, and ethnic minority women (especially African-American women) (Finer & Henshaw, 2006;Finer & Zolna, 2016;Henshaw, 1998).

Economic factors
The level of socio-economic development is often positively correlated with the level of unintended pregnancy. As mentioned earlier, global economic inequality is closely linked to geographical imbalances in the level of unintended pregnancy. Women's access to reliable, quality reproductive health information, and to contraceptive and safe abortion services are often limited in regions and countries with poorly developed economies (Bearak et al., 2020). A study using the Human Development Index (HDI) found that the level of education and per capita national income were inversely proportional to the level of unintended pregnancy in a given area (Bearak et al., 2022), and in areas where the level of education and per capita income were higher, the level of unintended pregnancy was lower. In addition, high levels of socio-economic development are often accompanied by social movements promoting the cause of gender equality and the improvement of women's social status. Poverty restricts women's access to high quality, safe contraceptives and abortion services, which in turn limits the ability of these women to realize their reproductive choices (Finer & Henshaw, 2006;Finer & Zolna, 2016). Previous studies have shown that economically disadvantaged women are more likely to have unprotected sexual intercourse than other women, and even when they use contraceptives, the risk of contraceptive failure is significantly higher (Finer & Henshaw, 2006). In addition, poverty often means lower levels of education and limited access to information, which in turn leads to insufficient awareness of pregnancy risks, contraceptive methods and reproductive health needs (Qi et al., 2013;Zheng et al., 2005), resulting in a higher risk of unintended pregnancy for this group of women. Previous studies using the gender inequality index (GII) have found that the higher the level of gender inequality, the higher the incidence of unintended pregnancy (Bearak et al., 2022). According to one study, between 2008 and 2011, women living below the federal poverty line and unmarried cohabiting women had a risk of unintended pregnancy two to three times higher than the United States average (Finer & Zolna, 2016).

Cultural factors
Culture is another macro factor that affects the level of unintended pregnancy. Cultural traditions including religious beliefs and preferences for male children affect access to and the use of contraceptives, and these, in turn, affect the level of unintended pregnancy (Singh et al., 2010). In addition, changing ideas of the family's role and fertility also affect the trend line for the level of unintended pregnancy. As societal norms regarding marriage and reproductive behavior have changed, most parts of the world have experienced or are experiencing an increase in the age at which people first marry and an accelerated de-coupling of sex, marriage and fertility. The growing preference for small families and the need to control the number and timing of births more precisely also place higher demands on the availability and quality of contraception (Singh et al., 2010). During the process of population transition, the level of unintended pregnancy in some areas tends to rise at first and then decrease: in the early stage, the level of unintended pregnancy increases because available contraceptive methods fail to meet the increasing demand for birth control, but then decreases gradually with the introduction and popularization of various contraceptive methods (Marston & Cleland, 2003).

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Analysis of unintended pregnancy and influencing factors… 2.3.3.3 Policy and service factors National and local policies and laws may affect the promotion of contraceptive information and the supply of contraceptive services, and then have a significant impact on the level of unintended pregnancy. For example, the implementation of fertility policy, increased awareness and knowledge of contraceptives, and the popularization of contraceptives have helped to reduce the number of unintended pregnancies and are due in part to declines in the fertility rates of some developing countries in recent years. According to one study, the proportion of married women using contraceptive methods in developing countries increased from 54 to 62% between 1990 and 2014 (Bearak et al., 2018). In addition, a country's legal framework also affects the supply of safe, reliable abortion services.

Individual factors
At the micro level, the quality of women's intimate relationships plays an important role in their ability to realize their reproductive choices. Support from partners has an important impact on women's use of effective contraception (Santelli et al., 2003). In many developing countries, gender inequality and sexual violence in intimate relationships are both causes of unintended pregnancies (Miller et al., 2010;Pallitto et al., 2005) and cause serious harm to women's reproductive health and mental health.
Studies in China have shown that unmarried cohabitation groups are at high risk of unintended pregnancy because they are generally young at the time of first sexual intercourse, have relatively high reproductive ability, are active sexually, and have little desire to bear children (Feng et al., 2011;Qi et al., 2013;Wei et al., 2020).
The most direct cause of unintended pregnancy is the failure of contraception and the non-use of contraception. In some cases, uncorrected use of contraception, such as COCs, condom and/spermicide, lead to failure. Culture and concerns about side effects influence the usage of contraception in some developing countries. Lack of accurate information of contraception leads to improper or non-use of contraception. Lack of affordable contraceptive services and the failure of contraceptive devices are common causes of unintended pregnancy (Li et al., 2014;Liu & Yan, 2014;Sedgh et al., 2016;Singh et al., 2010;Wang et al., 2013). According to United Nations estimates, about 257 million women who want contraception worldwide do not use safe, reliable contraception, and 172 million of them do not use any contraceptive method (UNFPA, 2022).
Although existing studies have recognized that contraceptive failure and non-use of contraception are the main causes of unintended pregnancy, there is a lack of indepth exploration of the causes of contraceptive failure or the non-use of contraception (Klima, 1998). In fact, be it macro level policy and the legal environment, the level of socio-economic development and culture, or the quality of their intimate relationships at the micro level, all of these factors profoundly affect women's ability to access contraceptive information and services in ways that affect the risk of unintended pregnancy and the realization of women's right to choose to give birth. Although the level of unintended pregnancy is declining in most regions, the incidence of unintended pregnancy in developing countries is still higher than that in developed countries, suggesting that developing countries need to pay attention to socio-economic development, changes in cultural, the popularity of contraceptive services, and the role of gender equality mechanisms to reduce unintended pregnancies.

Data sources and analysis methods
The data used in this study came from the China Fertility Survey 2017 organized by the former National Health and Family Planning Commission in 2017. The target population of the survey was Chinese women aged 15 and 60 who were living in mainland China at 00:00 on July 1, 2017. The survey adopted a probability sampling method of stratification, three stages and Probability Proportionate to Size Sampling (PPS) to cover 31 provinces (autonomous regions, cities) and the Xinjiang Production and Construction Corps. The survey included 6078 townships in 2737 counties (cities and districts); there was a total of 12,500 village (residential) level sample sites, and a total of 250,000 individual samples. The personal questionnaire collected information on four broad areas: fertility desire, fertility behavior, fertility care services and the main factors affecting fertility status; the investigation of fertility behavior included a complete "history of pregnancy". The China Fertility Survey 2017 collected only contraceptive methods after the last delivery/abortion, not previous contraceptive history. A computer-aided interview system (CAPI) was used in the survey.
This study used SPSS26.0 software to complete its analysis. Chi-square test and LOGISTIC regression were used for univariate and multivariate analysis.

Target objects
The data used in our analysis included three parts (Table 1). Part one consisted of data for all married women of childbearing age (15-49-year-old) to understand the development and changing trends of unintended pregnancy; part two consisted of data for married women of childbearing age with a history of pregnancy from 2010 to 2017 to analyze the factors influencing unintended pregnancy and induced abortion to end unintended pregnancy; part three consisted of data for married women of childbearing age (July 1, 2016 to June 30, 2017) to analyze the incidence rate of unintended pregnancy. The analysis involved only married women because the 2017 fertility survey did not ask unmarried women questions about pregnancy and fertility.

Analytical framework
The factor most directly influencing the occurrence of unintended pregnancy was the failure of contraception due to a failure to use effective contraceptive methods or the incorrect or unsustainable use of contraception before pregnancy. Previous research has shown that social and cultural context and personal factors have important indirect impacts on unintended pregnancy. This study focused on the indirect factors affecting unintended pregnancy. Based on the data available from the survey, we divided the indirect factors into two categories: social and cultural factors and personal factors (Fig. 1). When analyzing social and cultural factors, we chose whether a woman had a preference for boys, whether the woman's place of residence was urban or rural, and whether a relaxed fertility policy effectively reduced unintended pregnancy and the incidence of induced abortion. We wanted to determine whether women whose preference for a male child had not been satisfied had a lower risk of unintended pregnancy, and whether living in urban or rural areas affected the incidence of unintended pregnancy.
With respect to personal factors, we sought to determine whether women of childbearing age who were older had a lower desire to give birth and, thus, were likely to have a higher risk of unintended pregnancy and abortion. If women had more children, was the likelihood that their fertility desires had been satisfied higher, thus increasing the likelihood of unintended pregnancy? If the interpregnancy interval was short, did this mean that many women may not be ready for another pregnancy, thus increasing the risk of unintended pregnancy? Does the risk of unintended pregnancy increase if a woman's childbearing desire has been met? Are women in poor health especially vulnerable to the risks of unintended pregnancy and induced abortion?

Unintended pregnancy
Analysis of the data showed that the incidence of unintended pregnancy among married women in 2017 was 42.4‰, similar to that of 45‰ in developed countries from  (Bearak et al., 2018). The older the women were, the higher the incidence of unintended pregnancy. The incidence of unintended pregnancy was lowest in the group under 30 years old (34.5‰), second lowest in the group 30-39 years old (51.5‰), and highest in the group 40-49 years old (73.1‰).
Of women of childbearing age who had a history of pregnancy from 2010 to 2017, 22.9% of their pregnancies were unintended. As the age of women increased, the proportion of unintended pregnancy gradually increased. The lowest proportion of unintended pregnancies (16.8%) was among women under the age of 30, followed by the 30-39 age group (28.8%), and the 40-49 age group (54.9%).
The proportion of unintended pregnancies worldwide fell from 43% of all pregnancies in 1995 to 42% in 2008and 40% in 2012(Alan Guttmacher Institute, AGI, 1999Sedgh et al., 2014;Singh et al., 2010). In China, the proportion of unintended pregnancy has been less than 30% since 1990, which is lower than that of the global average. The proportion of unintended pregnancies increased gradually from 1990 to 2017, but declined rapidly after China's adjustment of fertility policy in 2016 (Fig. 2), which may be due to China's economic development, the improvement of family planning service policies, and the promotion of gender equity.

Unintended pregnancy and induced abortion
Although the number of women of childbearing age has declined, the number of induced abortions in China has remained above 8.   health, and consume a considerable amount of medical resources. The survey results show that between 2010 and 2017, 91.9% of all abortions terminated unintended pregnancies, while only 8.1% ended intentional pregnancies. It can be seen that unintended pregnancies have a great impact on the number of induced abortions. This means that preventing unintended pregnancies can greatly reduce the incidence of induced abortion. Further analysis found that of all unintended pregnancies, 71.9% ended in induced abortion, and only 19.9% ended with a live birth; the small remaining percentage ended in spontaneous abortion or stillbirth. Between 1990Between -1994Between and 2015Between -2019, the global proportion of unintended pregnancies ending in abortion has increased (Bearak et al., 2020). The proportion of induced abortion among unintended pregnancies in China is declining (Fig. 2), which is not consistent with the global trend, indicating that more and more families are choosing to have children rather than terminate pregnancies, even those that are unintended. which may be related to China's rapid economic development and the adjustment of fertility policy.

Variable description
The last pregnancy of a woman who was pregnant one or more times during the years 2010-2017 was selected as a dependent variable, with an unintended pregnancy assigned the value 0 and an intended pregnancy assigned the value 1. The survey ended in 2017. In order to avoid the bias caused by long-term memory errors, the pregnancy history from 2010 to 2017 was analyzed.
Fertility policy, preference for boy, and whether a woman's residence was in an urban or rural area were selected as social and cultural factors. Pregnancies were divided into two groups based on when they occurred: 2010-2013 and 2014-2017. The former group consisted of pregnancies before the fertility policy adjustment, and the latter group consisted of pregnancies after the fertility policy adjustment. The two groups were used to analyze the influence of fertility policy adjustment on unintended pregnancy. We divided women of childbearing age into those who gave birth to boys and those who did not in an effort to understand the impact of boy preference for children on unintended pregnancy. We also divided women into groups based on whether they lived in urban or rural areas in order to understand the impact of residential locale on unintended pregnancy ( Table 2).
The age of the woman at the time she gave birth, education level, and occupation were selected as control variables. Other personal variables included the number of children the woman had, her age when she gave birth, whether the woman's childbearing desire had been satisfied, the interpregnancy interval and the woman's personal health status. References to the number of children in this study refer to the number of children born prior to the woman's most recent pregnancy. Also, if the number of children born earlier is greater than or equal to number of children the woman expected to have, then this study considers fertility desire to have been Analysis of unintended pregnancy and influencing factors… satisfied. An interpregnancy interval of less than 2 years is set as a short interval, and 2 years or more is set as a long interval. This study recorded women's selfreported personal health status (healthy or unhealthy) ( Table 2). For individual data with true missing value, it is not included in the model. And a small number of classifications are merged, for example: women who give birth to 3-11 children, because the number is small, it is classified into a category of "giving birth to 3 or more" for calculation.

Factors influencing unintended pregnancy
The univariate analysis of the survey data found that factors such as living in an urban or rural area, whether boys had been born prior to the most recent pregnancy, the number of children, the age of the woman at the end of pregnancy, the interpregnancy interval and whether childbearing desire had been satisfied yielded different results. These factors all had important impacts on the occurrence of unintended pregnancy (chi-square test, P < 0.01), and fertility policy also had a significant impact on the occurrence of these pregnancies (chi-square test, P < 0.05).
In order to constrain the interaction among various factors, logistic regression analysis was carried out (Nagelkerke R 2 = 0.3422) ( Table 3). This analysis found that urban women were more likely to have an unintended pregnancy than rural women (1.5 times in Odds), and that women without a boy had a significantly higher risk of unintended pregnancy than women with a boy (1.5 times). A subconscious desire to have a boy may remain in some women who do not have boys, and the failure to take contraceptive measures or use effective contraceptive methods may be behavioral manifestations of such a desire. To a certain extent, failure to take contraceptive measure or use effective contraceptive method reflects the impact of boy preference for children on pregnancy. Our analysis found that fertility policy adjustment had no significant impact on the incidence of unintended pregnancy. At the time fertility policy was adjusted, we believed that the loosening of the policy would stimulate to a certain extent people's desire to have children, and the risk of unintended pregnancy would be reduced. However, the results of our analysis show that fertility policy adjustment has not had much impact. Of course, the loosened fertility policy has not been in place for long, and it is possible that its impact on fertility desire has yet to become apparent. Or the lack of impact may indicate that Chinese people's fertility desires have changed significantly over time. One thing is clear: To date the adjustment of fertility policy has not stimulated women's desire to have children.
After controlling for the birth cohort, education level, employment and other variables of women of childbearing age, the analysis found that, compared to women who had had no children, the risk of unintended pregnancy was 10 times higher for women who had one child, and 12 times higher for those with two children. However, the risk of unintended pregnancy for women with three children decreased to 8 times. The fact that women with 3 children had a lower risk of involuntary pregnancy than those with 1 or 2 children suggests that most women who have 3 children have the desire for 3 or more children, so the risk of unintended pregnancy is reduced. A short interpregnancy interval was found more likely to lead to unintended pregnancy; women with short intervals had 1.7 times greater risk of 1 3 Analysis of unintended pregnancy and influencing factors… Table 3 Analysis of factors influencing unintended pregnancy and induced abortion after unintended pregnancy unintended pregnancy than those with an interval of 2 years or more. This indicates that it is necessary to strengthen education about and advocacy for birth intervals of at least 2 years. The risk of unintended pregnancy for women who had satisfied childbearing desire was 5.9 times higher than it was for women whose desires were yet to be unsatisfied. Making contraceptive services readily available to those who satisfy childbearing desire can effectively reduce the risk of unintended pregnancy.

Factors influencing induced abortion after unintended pregnancy
Not all women who become pregnant unintentionally chose to have an induced abortion. According to the results of the survey, 71.9% of women with unintended pregnancies chose induced abortion, 6.7% of the pregnancies ended in spontaneous abortion, while only 19.9% of the women chose to give birth. The results of univariate analysis for these factors-residence in an urban or rural area, whether the survey respondent had or did not have a boy, the age of the woman at the end of pregnancy, differences in health status of the woman, differences in the number of children women had before the most recent pregnancy, whether the interpregnancy interval was more or less than 2 years, whether the childbearing desire had been met, and whether the pregnancy occurred before or after the fertility policy adjustment-each showed significant differences in the proportion of unintended pregnancies that ended with induced abortion (Chi-square test, P < 0.01).
Logistic regression was used to analyze the influence given factors had on the occurrence of induced abortion after unintended pregnancy (Nagelkerke R 2 = 0.2372) ( Table 3). After controlling for variables such as birth cohort, employment and education, the results showed that the risk of induced abortion after unintended pregnancy was 1.4 times higher in Odds for urban women than it was for rural women. This finding is related to the fact that urban women have less access to contraceptive services than rural women. The risk of abortion to end an unintended pregnancy was 1.8 times higher for women who had a male child than for women who did not. Women without boys were more likely to give birth to the child in the hope that the child would be a boy. To a certain extent, this reflects the impact of gender preference for children on abortion after unintended pregnancy. There was no significant difference in the proportion of unintended pregnancies ending in abortion before and after the adjustment of fertility policy. However, as Fig. 2 shows, the occurrence of induced abortion after unintended pregnancy since 2014 is trending downward overall.
Of note is the fact that the more times a woman had previously given birth, the lower the risk of her choosing induced abortion to end an unintended pregnancy. Women with one child who became unintentionally pregnant were 22 times more likely to end that pregnancy with abortion than was a woman who had no children. Women with two children who became unintentionally pregnant were 18 times more likely to end the pregnancy with abortion, and women with three children were 12 times more likely. Women whose interpregnancy interval was 2 years or less were at 2.4 times higher risk of induced abortion to end an unintended pregnancy than were women with intervals of more than 2 years; short intervals are not conducive to the upbringing of children born previously. Failure to control the length of the interval between pregnancies is an important factor leading to induced abortion after unintended pregnancy. Those who had satisfied their desire to have children had a 2.9 times higher risk of induced abortion to end unintended pregnancy than those who had not. Those who have more children are precisely those who have a greater desire to have children. This finding is also a reminder that contraceptive services to women who have satisfied their childbearing desires are inadequate. Women in poor health were somewhat less likely than women in good health to choose an induced abortion to end an unintended pregnancy. Women in the 35-49 age group at the time of an unintended pregnancy had a higher risk of induced abortion after the pregnancy than did women in the 25-34 and 15-24 age groups; that is, the older the woman was when she unintentionally became pregnancy, the more likely she was to abort the child rather than allowing the pregnancy to come to term. This suggests that older women of childbearing age, closer to menopause, are more likely to have an abortion to end an unintended pregnancy.

Post-abortion contraception
This study assumed that women who chose to have an abortion to end an unintended pregnancy would develop an enhanced sense of self-preservation and, after aborting an unintended pregnancy, would be more inclined to adopt effective contraceptive methods to protect themselves.
In fact, after ending an unintended pregnancy with induced abortion, 37.3% of women chose long-term contraception, compared with 41.7% of women who had had no abortion. Additionally, 56.1% of women who had induced abortion after unintended pregnancy chose short-term contraceptive methods such as condoms, a percentage significantly higher than the 50.9% of women who had had no abortion. This indicates that the warning effect on women who have induced abortion to end unintended pregnancy is not strong, and there is the possibility of repeated unintended pregnancies followed by repeated abortions. To increase the warning effect, more follow up services and better education targeting women who have an abortion to end an unintended pregnancy are called for.

Pay attention to the influence of social and cultural factors
Sociocultural factors affecting unintended pregnancy include residency in an urban or rural area and the gender preference for children; both of these factors also affect the likelihood of abortion after unintended pregnancy. The level of economic development is higher and medical services and education are better in urban areas than in rural areas, but women living in urban areas have a higher risk of unintended pregnancy than do women living in rural areas. This indicates that contraceptive services in urban areas may not be as easily accessible as in rural areas, or it may be due to a higher proportion of rural women using very effective contraceptive methods and fewer contraceptive failures. According to Family Planning: A Global Handbook for Providers (WHO, 2018), very effective contraceptive methods include method with a Pearl Index of less than 1, such as intrauterine device (IUD). How to strengthen the provision of contraceptive services in urban areas is a matter of concern. Women's gender preference for children is a key factor impacting the risk of unintended pregnancy and induced abortion after unintended pregnancy. Women who have already satisfied the desire to have a boy are at greater risk of unintended pregnancy and of having an abortion to end the unintended pregnancy. This indicates that followup contraceptive services need to be culturally sensitive and pay more attention to women who have already satisfied their gender preference for children.
The hypothesis was that the risks of unintended pregnancy and abortion to terminate the unintended pregnancy would decrease after two-child fertility policy adjustment in January 2016. In fact, the result of the multivariate analysis for fertility policy adjustment shows no significant change in the risks of unintended pregnancy and abortion before and after the adjustment. It is necessary to continue paying attention over the long term to the impact of the relatively recent adjustment to fertility policy; however, it may be the case that the impact of the policy factor is not pronounced.

Improve contraceptive services and expand the availability of services
China not only still has unmet demand for contraception, the level of unmet demand has trended upward in recent years (China Family Planning Association, 2020). We suggest strengthening the supply capacity of contraceptive services and the level of grass-roots technical services, based on the needs of women of childbearing age in different life cycle periods. Doing so can reduce the incidence of unintended pregnancy and induced abortion after unintended pregnancy.
The risks of unintended pregnancy and induced abortion to end the unintended pregnancy are higher for women who have already given birth to one child or two children, who have satisfied their childbearing desire, whose interpregnancy interval is short, and who are of relatively older childbearing age. We suggest increasing the supply of contraceptive services, paying particular attention to women of childbearing age who have 1 or 2 children, or whose childbearing desire is not strong. The inadequate provision of contraceptive services can easily lead to unintended pregnancies followed by induced abortions. There is a need to promote age-appropriate marriage, promote reasonable pregnancy intervals, and to strengthen the provision of contraceptive services to older women and women during pregnancy and childbirth. Such measures can reduce their risk of unintended pregnancy and induced abortion to end the unintended pregnancy.
After having an induced abortion to terminate an unintended pregnancy, only 37.3% of the women chose to use long-term contraceptive methods, suggesting that some women have a weak sense of self-preservation. It is thus important to provide high quality information and counseling services related to the prevention of unintended pregnancy, raise awareness of measures that reduce the risk of unintended pregnancy among women of childbearing age, and provide contraceptive counseling and guidance services to women after induced abortion to help women avoid repeated induced abortions. It is necessary to construct and improve on strategies designed to prevent unintended pregnancy, make use of key service nodes such as health examinations, marriage registrations, counseling on healthy pregnancy, prenatal examinations, hospital deliveries, and postpartum follow-up to implement basic contraceptive services and take the initiative to provide information. And it is important to promote the use of free contraceptive services. The key is to strengthen education that respects life and encourages responsible behavior and decisions at the family level.
The result of this study is the experience of China in the stage of developing countries, which can be used as a reference for developing countries. The results are limited by the survey data we chose. Some important issues concerning unintended pregnancy were not analyzed, such as the impact of unintended pregnancy on unmarried women and the use of contraception. The China Fertility Survey 2017 collected only contraceptive methods after the last delivery/abortion, not previous contraceptive history. It is necessary for scholars to investigate and evaluate in a timely manner changes in the demand for reproductive health services from Chinese women of different childbearing ages, and evaluate the effectiveness of existing services.
Data availability The data that support the findings of this study is available from National Health Commision of the People's Republic of China. The survey was conducted by China Population and Development Research Center.

Conflict of interest
We declare no conflict of interest.
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http:// creat iveco mmons. org/ licen ses/ by/4. 0/. Hui Wang is senior research fellow of China population and Development Research Center. Research interest: population health and reproductive health research. The vice chairman of the population health special committee of China Population Association. The executive director of nutrition monitoring and evaluation branch of Chinese Association for Student Nutrition and Health Promotion.