1 Introduction

Adequate maternal health care is effective to reduce negative birth outcomes including preterm delivery, low birthweight, maternal and infant mortality (Fan et al., 2017; UNICEF, 2008). Since the 1990s, China has kept focusing on promoting maternal health including facility birth and antenatal visits. The National Plan for Action of Children (1990s) was first outlined in 1992, and the Law on Maternal and Infant Health Care was issued in 1994. In 1999, the program of maternal mortality reduction and neonatal tetanus elimination was initiated by the National Working Committee on Children and Women of National Ministry of Health cooperated with UNICEF and WHO, and it was nationalized for all women to give birth in hospital free in 2009. Meanwhile, the National Plans for Action of Women (1995–2000, 2001–2010, and 2011–2020) were formulated and implemented continuously.

All these measures have taken effects, and China realized the millennium development goal of reducing maternal mortality ratio to a quarter in 2015. Maternal mortality decreased from 88.8 per 100,000 in 1990, 20.1 per 100,000 in 2015, to 18.3 per 100,000 in 2018 (NHC, 2019). It was reported in a national study covering the years 1997 to 2014 that utilization of healthcare varied widely among maternal populations, and that higher proportions of inadequate maternal healthcare were found regionally among women of childbearing age in both the central-west and the rural areas of China (Gao et al., 2017).

With social development since early 1980s, there are always big gaps between both the east and the central-west, and the urban and rural areas in China, although those have been fixing by the national government. It is estimated officially that internal migrants have increased substantially from 6.6 million in 1980 to 245 million in 2017, most of whom migrant from rural or underdeveloped areas to the developed or industrialized cities to earn money (NHC, 2018).There are almost half women of reproductive age with relatively lower education among internal migrants, their adequate maternal healthcare is an important issue of public health (Gong, Wang, & Liu, 2017a).

With maternal healthcare promoted continuously in China, the proportion of hospitalization has increased from 60.7% in 1996 to approximate 100% nationally in 2018, and that contributes to maternal and aeonatal mortality decreasing (NHC, 2019). It is reported that maternal mortality has decreased from 63.9‰ to 17.8‰, and that infant mortality from 24‰ to 3.5‰ between 1996 and 2020 (NBS, 2020). Although pervious gaps on hospitalization are almost eliminated between regions, disparities on maternal and infant mortality exist still with relative higher mortality in rural and under-developed regions. The proportion of system management of maternal healthcare specified by The Law on Maternal and Infant Health Care has increased from 65.5% in 1996 to 89.9% in 2018, but migrant women do not have much maternal healthcare as the local in their receiving areas (NHC, 2019; NBS, 2018).

Female migrants of childbearing age utilize lower level of maternal health services than the local population (Boerleider et al., 2013). Regarding prenatal care, a national study reported that 85.4% of migrant women got a Handbook of maternal and child Health Care (HHC), and that 79.5% had 5 or more prenatal visits (Gong et al., 2017a). Some regional studies revealed that migrants were less possible to get a HHC timely (42.9% vs. 93.7% in Pujing), and much later to get a HHC (19 vs. 15 weeks in Ningbo) than the local (Ding, 2020; Zhang et al., 2019). They are also more likely to have inadequate prenatal examinations (81% vs. 90.8% in Beijing; 84.4% vs. 91.7% in Jiangsu province) compared to those long-term residency women in the receiving areas (Gu, You, & Ning, 2017; Tian et al., 2019).

As for postnatal care, migrant women were also found less service utilization of a seventh-day visit (40.6% vs. 91.3%) and a 42nd-day examination (44.7% vs. 60.9%) than the local women (Ding, 2020; Liu et al., 2019). One national study reported that 77.3% migrant women had a 42nd-day examination after the recent delivery (Gong, Wang, & Liu, 2017b). Another found only 64.2% of those after their second birth had a 42nd-day examination, and that 13.9% had never utilize any maternal healthcare service (Shi & Liu, 2018).

Different factors are found associated with maternal healthcare among migrant women. Higher education, higher income, maternal insurance and first pregnancy were significantly correlated to adequate maternal healthcare (Gong et al., 2017b; Tang et al., 2019a, Tang et al., 2019b; Zhang et al., 2012), but some studies reported migration characteristics including current status and history had positive and negative effects on adequate maternal healthcare individually (Gu, You, & Ning, 2017; Tang et al., 2019a, Tang et al., 2019b).

Previous studies among migrant women in China have reported such important results that demographic characteristics and migration experience are significantly associated with their maternal healthcare, but the effect of their childbearing history except birth order was not given enough consideration and discussion (Chen, 2019; Gu et al., 2017; Ji et al., 2018). In this study, we provided a relatively full analysis on service utilization of maternal health, and examined associations between two groups of factors and maternal healthcare using a dataset from a sampling survey of married migrant women aged 20–39 years in Changzhou, China in 2018.

2 Methods

2.1 Setting

The Law on Maternal and Infant Health Care specified clear guidelines for maternal healthcare of women. Specification on National Basic Public Health Services recommended getting a HHC with a prenatal care taken in the first 12 weeks of pregnancy at the community medical center, at least 5 prenatal examination, receiving a home visit in 7 days and having a 42nd-day examination after delivery, and screening and further examination should be taken if abnormal symptoms are detected (NHFPC, 2017). There are not professional midwives, and delivery at home is usually forbidden in China. Qualified doctors and nurses in hospital provide maternal healthcare, and the health insurance systems, which more than 95% of residents enjoy, cover regular service of maternal health.

2.2 Data collection

We collected the cross-sectional data for this article in a questionnaire-based study of reproductive health and service among married female migrants of 20–39 years in Changzhou city. Changzhou is one of the typical cities in eastern China where the local residents cannot meet the huge demand for labor with socio-economy and manufacturing sector developing rapidly and a large quantity of labor population migrate there to work, most of whom are from rural and undeveloped areas. In 2018, Changzhou was projected to hold 1.76 million migrants, accounting for a third of the total population approximately, most of whom are manufacturing workers in factories, and about 75% of migrant population including almost 0.66 million migrant women are aged 20–39, to whom maternal healthcare is crucial (CBS, 2019; Ding, Zhang, & Du, 2018).

To collect data, purposive sampling was used to select 12 factories from five municipal districts manufacturing different products covering clothing, electronics, and auto parts. To get a representative sample in every sampled factory, systematic sampling was used based on working ID numbers of migrant women aged 20–39 years with a 10% sampling fraction, and 50–150 women were selected correspondingly in each factory. Our sample size was 801, and 373 married migrant women aged 20–39 who had a delivery history since the recent 5 years were screened for the sub-sample of this study to reduce recall bias.

After a pretest with 15 married migrant women we developed a self-administered questionnaire. Measuring contents of the questionnaire included social demographic characteristics, working and internal migration history, pregnancy and maternity, utilization of maternal services. After consent from management of each sampled factory, the field survey was conducted by 28 trained investigators, 2–3 of whom administered questionnaires in each of 12 factories over 1–3 days. A list of sampled women was provided by a survey coordinator for the head of each factory, and then they were invited to the factory infirmary to administrate a questionnaire at their free will after work shift. Researchers explained the study before oral consent was obtained, and respondents were told the survey was anonymous. It is so common for rare refusals for interviewed survey in China that refusals were not recorded. It took about 20 min for respondents completing the questionnaire and they received a little gift valued at US$5.

2.3 Independent variables

We analyzed two main groups of independent variables including social- demographic characteristics and childbearing history. With those similar factors considered in previous studies (Gong et al., 2017b; Gu et al., 2017), one group of social-demographic characteristics included age, education level, income, area of origin and maternity insurance; another group of childbearing history included birth order, birth year and location in maternal duration. Location in maternal duration indicated different maternal health service contexts to some extent, and taking birth year as an independent variable indicated the secular trend of maternal healthcare especially in different policy contexts with the two-child fertility policy implemented since 2016. Associations were also examined between these two independent variables and maternal healthcare among migrant women.

Regarding the demographic variables, age was coded into 2 categories: 20–29 and 30–39 years; educational level was divided into 3 categories: junior, senior high school and college; average personal income per month (CNY) was grouped into < 3000, 3000–4000, and ≥ 4000; area of origin was coded into the interior of Jiangsu province and other provinces; whether having maternity insurance was coded into yes or no. About childbearing history, birth year of the younger child was coded into 2016–2018 and 2013–2015; birth order of the younger child was divided into first and second (for only 9 respondents have 3 or 4 children their order of the younger child was merged into the category of second); location in the maternal duration of the younger child was coded as Changzhou and hometown.

2.4 Dependent variables

Four dependent variables were considered in this study. The first was “Did you get a HHC in the first trimester of your recent pregnancy” with an answer of “yes” or “no”; the second was whether respondents had adequate prenatal visits(≥ 5) during the recent pregnancy period, which was recoded from the question “how many prenatal visits did you have in a period of your recent pregnancy”; the third was “Did you receiving a seventh-day home visit after delivery of the younger child” with an answer of “yes” or “no”; the last was “Did you have a 42nd-day examination after delivery of the younger child” with an answer of “yes” or “no”.

Regarding the reliability of these 4 items, the Cronbach’s α is 0.852. Exploring factor analysis was used to analyze construct validity, KMO statistics is 0.71 > 0.7, and Bartlett's Test of Sphericity is significant (p = 0.000 < 0.05). These four items of prenatal and postnatal health were associated strongly with a factor explaining maternal health, and their factor loadings were 0.896, 0.904, 0.687, and 0.867 individually.

2.5 Statistical methods

Data were analyzed with SPSS version 20. We examined bivariate associations using Chi-square test between dependent and independent variables. We fitted multivariate logistic models to assess independent predicators of four dependent variables including social-demographic characteristics and childbearing history that were considered significant at level of p < 0.05.

3 Results

3.1 Sample characteristics

The sample consisted of 373 respondents. As shown in Table 1, 51.2% of married migrant women were aged 20–29 years, 54.2% had junior high school education, only 32.7% had personal average income of more than 4000 CNY monthly, 68.6% had rural household registration, 73.7% migrated from other provinces, and 33.2% had maternity insurance. Regarding childbearing history, 48.5% of women’s younger children were born in 2016–2018, 55.2% only had one child, and 42.1% stayed in Changzhou in the recent maternal duration.

Table 1 Sample composition (N = 373)
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3.2 Getting a HHC in the first trimester

Regarding a HHC, 30% of migrant women reported that they did not get a HHC timely in the first trimester of pregnancy, and four respondents could not remember it clearly. Among 269 women with complete data as presented in Table 2, bivariate predictors of not getting a HHC in the first trimester included lower educational level, no maternity insurance, hometown in other provinces, returning hometown in maternal duration, and higher birth order.

Table 2 Bivariate predictors of inadequate maternal healthcare
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Only three variables were significant in the logistic model presented in the first column of Table 3, and having no maternity insurance, hometown in other provinces and the second child had independent associations with no establishment of a HHC in time. Migrant women in their pregnancy of the second child were more unlikely to get a HHC in the first trimester, and birth year of the younger child and location in maternal duration did not reach statistical significance.

Table 3 Multivariate predictors of inadequate maternal health
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3.3 Inadequate prenatal visits

Among 268 respondents excepting five remembering unclearly, 4.6% of them had 1–2 prenatal visits, 15.5% had 3–4, 34% had 5–7 and 45.9% had eight or more in the period of their recent pregnancy. Totally, 20.1% of married migrant women with less than five visits had inadequate prenatal care. Bivariate predictors of absent prenatal visits included no maternity insurance, higher birth order (Table 2). Migrants with lower educational level and staying in hometown during maternal period were also more likely to inadequate prenatal care although these two predictors were not quite significant (p = 0.056 and 0.052 individually).

Multivariate associations were shown in the second column of Table 3 with absent antenatal care, and two independent variables of childbearing history were significant. Married migrant women who had an earlier birth and who had a second child were more likely to have inadequate prenatal care, but location in maternal duration had no significant effect.

3.4 Postnatal healthcare

Regarding postnatal services, 37% of married migrant women reported that they had not received a seventh-day home visit after the recent delivery by community medical staff. Significant bivariate predictors for no this home visit included educational level, personal income, location in maternal duration (Table 2). The logistic regression of no seventh-day home visit in the third column of Table 3 shows that only age, income and staying in Changzhou during maternal period were significant, and that others variables were not independent predictors for a seventh-day home visit after delivery.

Most of married migrant women reported having a 42nd-day examination after delivery, but 16.4% had no such postnatal healthcare. Bivariate predictors of no postnatal check included lower educational level, having no maternity insurance and location in maternal duration (Table 2). The logistic model was fitted to examine independent predictors of no 42nd-day check as shown in the last column of Table 3. Migrant women who had lower educational level and who returned hometown during maternal period were more probable to have no postanal examination, and higher birth order was also more likely to be associated with no postnatal check although p value (0.07) was not less than 0.05.

4 Conclusion and discussion

In this study substantial married migrant women of 20–39 years in Changzhou, China reported inadequate utilization of maternal healthcare, and childbearing history including birth year, higher birth order and location in maternal duration have significant effects. Their personal experience and institutional obstacles could be involved so that adopting feasible measures is crucial to improve their scientific maternal health awareness and ability of accessing maternal health care and to improve maternal healthcare providing.

Proportions of different absent maternal healthcare ranged from 16.4% to 37% respectively among migrant women in Changzhou. The prevalence of maternal healthcare utilization among married migrant women in this study were consistent with a study of national migrants in 2017, but lower than the local population (Han, 2011; Han, Chen, & Lin, 2017). Migrant women also have relatively higher maternal mortality resulted mainly from inadequate maternal care, and decreasing the maternal mortality among migrant women is one key goal of the National Plan for Action for Women (2011–2020) (Tang et al., 2008; Zhang et al., 2014).

An interesting finding was that migrant women who stayed Changzhou in their maternal duration had better utilization of maternal healthcare service than those returning hometown. These similar results were reported in a previous national study that only focused on prenatal care among migrant women (Zong et al., 2018), and this study further demonstrated positive associations between postnatal care and receiving areas. Migrant women with better maternal service in Changzhou suggest two points, demand and supply. One is better access to health service in Changzhou compared to their underdeveloped hometown for migrants. Those migrant women, who stayed Changzhou in their maternal duration and imitated the local residents in their receiving communities, were more likely to utilized adequate maternal healthcare actively and meet their health demand.

Another is that relatively higher-quality of maternal care system in Changzhou ensure migrant women could enjoy better service while equality to basic health service was kept promoting with 95% coverage proportion of a basic healthcare goal among migrants achieved in 2030 (CG, 2017a). Meanwhile, earlier birth year of childbearing history associated with inadequate maternal healthcare may be the secular trend. The better utilization of maternal health services for the younger child showed that prevalence of maternal healthcare kept rising among married migrant women in spite of relatively lower than the local in the receiving communities in the past years (NHC, 2019).

Higher birth order positively associated with absent utilization of maternal healthcare was also a significant finding in this study. These negative associations probably were involved with personal experience. Previous childbearing experience maybe an obstacle for adequate maternal healthcare. According to personal maternal history, migrant women could not go to a doctor but make empirical judgement when they feel well, although these decisions instead of professional healthcare will definitely expose migrant women to higher risks for negative maternal outcomes (Yao et al., 2013). In addition, more or less overtreatment they had in hospital may also prevent migrant women from enough maternal healthcare. The model of maternal healthcare is facility-based and doctor-led in China, and now large hospitals have been equipped with much advanced technology and costly interventions. Many migrant women have excessively medicalized pregnancies and deliveries with unnecessary check and treatment, but they have to pay these items out-of-pocket that are usually not covered by their health insurance (Yao et al., 2013). In this point, it is probably easy to understand why some migrant women who have another child would rather monitor their maternal health by themselves than look for professional service.

Consistent with findings from previous studies, migrant women of childbearing age who usually are in lower socio-economic status with farther migration distance are more likely to have inadequate maternal healthcare, and those who have maternity insurance are more possible to have adequate maternal services (Gu et al., 2017; Ji et al., 2018).The goal of maternal and child health in 2020 is to sustain maternal and infant mortality less than 6 per 100,000 and 5‰ individually in Changzhou, and available work on reducing maternal and infant mortality among migrant women looks more important (CG, 2017b).

International studies also found that migrant women had inadequate maternal healthcare (Phillimore, 2016; Renzaho & Oldroyd, 2014). Less than a third of migrant women received basic prenatal care in their receiving areas in India, factors including lower socio-economic status, different cultural background of origin and lack of social support prevent migrant women accessing adequate prenatal and postnatal healthcare (Gawde, Sivakami, & Babu, 2016; Yu, Bowers, & Yeoh, 2020).

There are several limitations in this study. We cannot examine causation but association using a cross-sectional dataset. Retrospective self-reported data may have recall bias, and 4–10 respondents could not remember their maternal healthcare information clearly. A non-migrant group was not included for direct comparison. Results of this study in 12 factories may not generalize to other migrant women, but there are thousands of married migrant women working in Changzhou who likely face similar problems, as may other migrant women elsewhere in China and in other industrializing countries. So, we believe this study provides useful information about married migrant women at risk for maternal health.