Abstract
Purpose
This study aimed to analyze the current status of women’s perception of social support levels, psychological resilience, anxiety, and depression levels during IVF-ET, as well as investigate the influence of perceived social support and psychological resilience on the anxiety and depression levels of women undergoing IVF-ET and the mediating role of psychological resilience in this process.
Methods
In this study, a convenience sampling method was used to administer a questionnaire survey among 433 women undergoing IVF-ET. Then, multivariate linear regression models were applied to identify factors influencing anxiety and depression. Lastly, mediation effect analysis was conducted to explore the mediating role of psychological resilience.
Results
The incidence of anxiety and depression was 42% and 46.4%, respectively. The mean score of the Perceived Social Support Scale (PSSS) indicated a high to moderate level of support, while the mean score of the Conner-Davidson Resilience Scale (CD-RISC) suggested moderate psychological resilience. Perceived social support was positively correlated with psychological resilience, and both were negatively correlated with anxiety and depression. Perceived social support and psychological resilience were identified as influencing factors of anxiety and depression (P < 0.001). Moreover, there was a partial mediating effect of psychological resilience between perceived social support and both anxiety and depression (P < 0.01).
Conclusions
These results highlight the need for healthcare providers to assess patients’ levels of psychological resilience and perceived social support when developing mental health interventions in order to mitigate the risk of anxiety and depression and concomitantly enhance fertility outcomes.
Keywords: Perceived social support, Psychological resilience, Anxiety, Depression, Mediating effect
Introduction
Infertility, as a unique reproductive health concern, directly influences the physical and mental health of patients, family harmony, and social stability [1]. Previous studies have reported that both infertile patients and their spouses face varying degrees of reproductive pressure, which has a negative predictive effect on quality of life [2]. In the specific socio-cultural context of mainland China, marriage is a key component of social structure. In the field of assisted reproductive technology (ART) treatment, marital status is typically a prerequisite for participation, which may differ from practices in Western countries. Influenced by traditional ideas such as “having no descendants is a great loss,” infertile patients and their spouses in China bear tremendous psychological pressure, which affects family stability [3]. Infertility is generally regarded as a failure for the individual or the family, leading to considerable pressure from family and society [4]. Moreover, social beliefs and stigma surrounding in vitro fertilization treatment remain prevalent, which may adversely impact the mental health of patients and treatment decisions.
In recent years, in vitro fertilization-embryo transfer (IVF-ET) has been extensively utilized in the treatment of infertility patients. It involves processes such as superovulation, oocyte retrieval, sperm collection, in vitro fertilization, embryo culture, embryo transfer, luteal support, and confirmation of clinical pregnancy through serological and ultrasound examinations. The entire treatment cycle is long and complex, easily leading to negative emotions such as anxiety and depression. In severe cases, it can result in psychological disorders. A study reported that negative emotions such as anxiety and depression can affect the quality of the reproductive life of patients undergoing IVF-ET [5]. Earlier research established that approximately 25.2% of women undergoing IVF-ET treatment exhibit varying levels of anxiety symptoms, while 31.3% manifest varying degrees of depressive feelings [6]. These findings highlight the need for healthcare professionals to assess the levels of anxiety and depression in women undergoing IVF-ET and offer personalized psychological support and intervention to promote fertility health and improve treatment outcomes.
Perceived social support refers to the degree of support that individuals feel from family, friends, or other sources. Compared to actual social support, perceived social support can be used to predict and assess an individual’s mental health status [7]. Studies have found that family dysfunction and insufficient utilization of family support may further exacerbate the psychological condition of female infertility patients [8]. Other studies indicated that family function is closely related to the mental health of infertile women with family dysfunction potentially being a major factor leading to psychological distress and treatment discontinuation [9]. In addition, this study particularly focused on the norms of family support and information disclosure. In traditional Chinese culture, the family is frequently regarded as the primary source of emotional and material support, and infertility patients may opt to withhold information regarding their treatment status due to fear of discrimination or shame [10]. Therefore, elucidating the psychological state and perceived social support of patients in this context is crucial for developing effective intervention measures.
Psychological resilience refers to an individual’s ability to adapt well and recover in the face of adversity, which can help patients adjust their mindset and face challenges with optimism [11]. Previous research demonstrated that psychological resilience, as an important protective factor for mental health, is associated with the level of perceived social support [12]. Some studies described that psychological resilience plays a partial mediating role in the relationship between reproductive pressure and depressive symptoms in women with infertility, but have overlooked the effect of perceived social support [13]. Other studies indicated that psychological resilience exerts a partial mediating effect between the stigma experienced by women with infertility and depression, but similarly ignored the significance of perceived social support. Therefore, existing research has not comprehensively explored the relationship and mechanism of action between anxiety, depression, psychological resilience, and perceived social support in women undergoing IVF-ET.
Based on this, this study aimed to investigate the impact path of psychological resilience and perceived social support levels on anxiety and depression in women undergoing IVF-ET to identify potential mechanisms influencing anxiety and depression and provide theoretical evidence and empirical support for clinical healthcare professionals to alleviate anxiety and depression in women undergoing IVF-ET.
Subjects and methods
Subjects
This study employed the convenience sampling method, and promotional posters (The posters publicizing the purpose of the study, participation criteria, and potential benefits.) were posted at a reproductive center in a Grade A tertiary hospital in Zhejiang Province, China. All female patients undergoing IVF-ET who had registered at the center were invited to participate in the study. A total of 433 female patients undergoing IVF-ET were eventually recruited as survey subjects from June 2023 to December 2023. The inclusion criteria includes:(1) women aged 20 years or older and undergoing IVF-ET treatment at our hospital; (2) women with a minimum educational attainment of junior high school who can recognize and understand the Chinese language without communication impairments; (3) women with clear consciousness, no history of severe mental illness, and willing to participate in this study. The exclusion criteria includes: (1) women who had experienced other negative life events during the same period; (2) women participating in other clinical drug trials or psychological interventions. The required sample size for this study was estimated using the Kendall method. Based on the total number of study variables (23), the sample size (n) was calculated to be 23 times the number of variables (10 to 15 times), resulting in a target of 230 to 345 cases. Considering a 20% margin of invalid questionnaires, the required sample size for this study was adjusted to 276 to 414 cases. Ultimately, a total of 433 cases were included in the study.
Methods
This study employed a cross-sectional research design. Two trained investigators conducted face-to-face interviews with study participants 1 day before ovarian follicle aspiration to ensure that the research subjects could independently fill out the paper questionnaire without disruption. A standardized script was used to explain the purpose of the study, and informed consent was obtained from all participants who met the inclusion and exclusion criteria. The questionnaires were distributed and collected on-site, and investigators promptly instructed participants to complete any missing or incomplete items. A total of 450 questionnaires were distributed, and 433 valid questionnaires were recovered, yielding a recovery rate of 96.2%. During this process, the number of research subjects who did not meet the inclusion/exclusion criteria and their specific reasons were thoroughly recorded. Specifically, a total of 17 women were excluded from this study for the following reasons: (1) Seven were excluded due to obviously patterned responses; (2) Four were excluded because they were unable to understand or sign the informed consent form; (3) Six withdrew from the study for personal reasons.
Tools
General information questionnaire
The research team designed a general information questionnaire consisting of two sections, namely the social demographic data and fertility challenge-related data sections. The former included age, educational attainment, occupation, place of residence, age at marriage, annual family income, and types of family financial support, whereas the latter encompassed the number of pregnancies, number of births, duration of infertility, sources of family stress, number of treatment cycles, treatment costs, causes of infertility, and comorbidities.
Perceived social support scale (PSSS)
The PSSS, developed by Zimet et al. [14] and revised by Jiang [15], is a tool designed to evaluate the level of social support perceived by individuals. This support, crucial for an individual’s mental health and their ability to cope with life’s stressors, originates from sources such as family, friends, and colleagues. The scale consists of 12 items and covers three dimensions: family support, friend support, and support from others. It uses a 7-point Likert scale, with scores ranging from 1 to 7, and the total score ranging between 12 and 84. A score of 12–36 indicates a low level of social support, 37–60 indicates a moderate level, and 61–84 indicates a high level. Higher scores on the scale indicate greater perceived social support. The Cronbach’s α coefficients for the dimensions of the scale range from 0.799 to 0.831, indicating good reliability and validity. In the current study, the Cronbach’s α coefficient for the scale was 0.855, highlighting its reliability.
Conner-davidson resilience scale (CD-RISC)
The CD-RISC is a widely used measure of psychological resilience developed by Conner and Davidson [16]. It assesses the ability to cope with and recover from adversity, trauma, and stress. The scale consists of 25 items and assesses three dimensions of resilience, namely perseverance, strength, and optimism. The items are rated on a 5-point Likert scale, with scores ranging from 0 to 4. The total score on the scale ranges between 0 and 100, with scores of 0–40 indicating a low level of psychological resilience, 41–80 indicating a moderate level, and 81–100 indicating a high level. Higher scores on the scale indicate greater resilience. The Cronbach’s α coefficients for the dimensions of the CD-RISC range from 0.705 to 0.871, indicating good internal consistency and reliability. In the present study, the Cronbach’s α coefficient for the scale was 0.846, highlighting its reliability.
Generalized anxiety disorder-7 (GAD-7)
The GAD-7 is a brief self-report questionnaire developed by Spitzer et al. [17] based on the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) diagnostic criteria. It is used to screen individuals for generalized anxiety disorder (GAD) and assess the severity of anxiety symptoms. It comprises seven items and uses a 4-point Likert scale for rating, with scores ranging from 0 to 3. Higher scores on the GAD-7 indicate higher levels of anxiety. In the present study, the Cronbach’s α coefficient for the GAD-7 was 0.800, indicating robust reliability.
Patient health questionnaire (PHQ-9)
The PHQ-9 is a self-report questionnaire developed by Kroenke et al. [18] in 2001 based on the DSM-IV. It is used for the screening and diagnosis of depressive disorders. The PHQ-9 consists of nine items and uses a 4-point Likert scale for rating, with scores ranging from 0 to 3. Higher scores on the PHQ-9 reflect more severe depressive symptoms. In the current study, the Cronbach’s α coefficient for the PHQ-9 was 0.801, indicating good reliability for clinical use.
Statistical analysis
The database was established using Excel software, and statistical analyses were conducted using SPSS25.0 software. Patient general information was expressed as counts and constituent ratios. Measured data that conformed to a normal distribution were expressed as means. Independent sample t-tests and analysis of variance (ANOVA) were used for univariate analysis. Pearson correlation analysis was employed to explore the relationship between psychological resilience, perceived social support, and anxiety and depression. A multiple linear regression model was applied to investigate factors influencing anxiety and depression. Mediation effect analyses were conducted using the Process plugin in SPSS software. A P-value of less than 0.05 was considered statistically significant.
Results
General information
The age of the 433 study subjects ranged from 21 to 47 years (32.93 ± 4.71), with individuals over the age of 35 accounting for 34.9% of the cohort. The anxiety score of women undergoing IVF-ET was 4.44 ± 3.07, with an incidence rate of 42%. Similarly, the depression score was 4.40 ± 3.07, with an incidence rate of 46.4%. The general information of patients is presented in Table 1. The average scores for patient anxiety, depression, perceived social support, and psychological resilience are presented in Table 2.
Table 1.
Comparison of anxiety and depression scores among women with different characteristics undergoing IVF-ET
| Variable | Group | Cases (%) | GAD-7 | PHQ-9 | ||||
|---|---|---|---|---|---|---|---|---|
| Scores | Statistics | P | Scores | Statistics | P | |||
| Age | –0.298a | 0.766 | –0.494a | 0.622 | ||||
| 20–34 y | 282 (65.1) | 4.40 ± 3.12 | 4.34 ± 2.98 | |||||
| ≥ 35 y | 151 (34.9) | 4.50 ± 2.98 | 4.50 ± 3.23 | |||||
| Educational attainment | 16.904b | < 0.001 | 17.061b | < 0.001 | ||||
| Junior high school and below | 85 (19.6) | 5.55 ± 3.07 | 5.72 ± 3.43 | |||||
| High school | 66 (15.2) | 6.08 ± 3.37 | 5.82 ± 3.14 | |||||
| University | 200 (46.2) | 3.70 ± 2.48 | 3.70 ± 2.47 | |||||
| Postgraduate and above | 82 (18.9) | 3.77 ± 3.31 | 3.59 ± 3.12 | |||||
| Marital status | –2.12a | 0.035 | –1.536a | 0.125 | ||||
| First marriage | 366 (84.5) | 4.30 ± 3.02 | 4.30 ± 3.01 | |||||
| Remarriage | 67 (15.5) | 5.16 ± 3.26 | 4.93 ± 3.33 | |||||
| Residence | 4.437a | < 0.001 | 4.874a | < 0.001 | ||||
| Rural | 162 (37.4) | 5.31 ± 3.39 | 5.30 ± 3.09 | |||||
| City | 271 (62.6) | 3.92 ± 2.73 | 3.86 ± 2.93 | |||||
| Family annual income (million yuan) | 10.325b | < 0.001 | 14.364b | < 0.001 | ||||
| < 10 | 145 (33.5) | 5.38 ± 3.18 | 5.50 ± 3.35 | |||||
| 10–30 | 176 (40.6) | 4.30 ± 2.91 | 4.26 ± 2.81 | |||||
| 30–50 | 60 (13.9) | 3.92 ± 2.76 | 3.63 ± 2.42 | |||||
| > 50 | 52 (12) | 2.88 ± 2.84 | 2.67 ± 2.58 | |||||
| Working condition | –0.788a | 0.431 | 0.344a | 0.731 | ||||
| In-service | 365 (84.3) | 4.71 ± 3.08 | 4.51 ± 3.01 | |||||
| Jobless | 68 (15.7) | 4.39 ± 3.07 | 4.38 ± 3.08 | |||||
| Husband employment status | 1.498a | 0.135 | 1.192a | 0.234 | ||||
| In-service | 419 (96.8) | 5.64 ± 4.01 | 5.36 ± 3.27 | |||||
| Jobless | 14 (3.2) | 4.40 ± 3.03 | 4.37 ± 3.06 | |||||
| Family economic source | 1.333b | 0.265 | 2.295b | 0.102 | ||||
| Both sides | 376 (86.8) | 3.67 ± 3.06 | 7.00 ± 2.00 | |||||
| Male | 54 (12.5) | 5.06 ± 3.34 | 4.98 ± 3.75 | |||||
| Female | 3 (0.7) | 4.35 ± 3.02 | 4.29 ± 2.95 | |||||
| Causes of infertility | 3.293b | 0.038 | 2.047b | 0.130 | ||||
| Male | 68 (15.7) | 3.59 ± 2.93 | 3.82 ± 2.58 | |||||
| Female | 231 (53.3) | 4.50 ± 2.96 | 4.35 ± 3.10 | |||||
| Both sides | 133 (30.7) | 4.73 ± 3.26 | 4.74 ± 3.19 | |||||
| Infertility time (years) | 18.789b | < 0.001 | 7.179b | 0.001 | ||||
| < 5 | 357 (82.4) | 4.32 ± 2.76 | 4.27 ± 2.90 | |||||
| 5–10 | 44 (10.2) | 6.66 ± 4.11 | 5.95 ± 3.31 | |||||
| > 10 | 32 (7.4) | 2.63 ± 3.09 | 3.63 ± 3.90 | |||||
| Number of abortions | 0.342b | 0.795 | 1.057b | 0.367 | ||||
| 0 | 242 (55.9) | 4.50 ± 3.10 | 4.48 ± 2.92 | |||||
| 1 | 97 (22.4) | 4.21 ± 3.13 | 4.01 ± 3.24 | |||||
| 2 | 48 (11.1) | 4.69 ± 2.97 | 4.92 ± 3.32 | |||||
| ≥ 3 | 46 (10.6) | 4.33 ± 2.95 | 4.26 ± 3.17 | |||||
| Fertility pressure | 0.453b | 0.636 | 0.355b | 0.701 | ||||
| Own | 290 (67.0) | 4.47 ± 2.94 | 4.34 ± 3.02 | |||||
| spouse | 69 (15.9) | 4.59 ± 3.38 | 4.68 ± 3.34 | |||||
| Relative | 73 (16.9) | 4.14 ± 3.29 | 4.36 ± 3.01 | |||||
| Treatment time | 12.624b | < 0.001 | 16.037b | < 0.001 | ||||
| 1 | 225 (52.0) | 5.01 ± 2.87 | 5.12 ± 2.95 | |||||
| 2 | 92 (21.2) | 4.48 ± 2.85 | 4.07 ± 2.65 | |||||
| ≥ 3 | 116 (26.8) | 3.29 ± 3.30 | 3.25 ± 3.33 | |||||
| Treatment expense (million yuan) | 3.389b | 0.035 | 5.327b | 0.005 | ||||
| < 3 | 198 (45.7) | 4.78 ± 3.14 | 4.87 ± 3.05 | |||||
| 3 ~ 8 | 137 (31.6) | 4.39 ± 2.94 | 4.21 ± 2.86 | |||||
| > 8 | 98 (22.6) | 3.81 ± 3.03 | 3.69 ± 3.23 | |||||
a, t statistic; b, F-statistic; GAD-7, Generalized anxiety Disorder-7; PHQ-9, Patient Health Questionnaire
Table 2.
Mean ± standard deviation of anxiety, depression, psychological resilience, and perceived social support in women undergoing IVF-ET
| Items | Mean ± SD |
|---|---|
| GAD-7 | 4.44 ± 3.07 |
| PHQ-9 | 4.40 ± 3.07 |
| PSSS | 64.54 ± 10.69 |
| Family support | 22.68 ± 3.94 |
| Friend support | 20.92 ± 4.33 |
| Other support | 20.95 ± 4.00 |
| CD-RISC | 64.07 ± 14.73 |
| Perseverance | 31.70 ± 8.29 |
| Force | 21.94 ± 4.91 |
| Optimism | 10.43 ± 3.27 |
GAD-7, Generalized anxiety Disorder-7; PHQ-9, Patient Health Questionnaire; PSSS, Perceived Social Support Scale; CD-RISC, Conner-Davidson Resilience Scale; Mean ± SD, Mean ± standard deviation
Correlation between perceived social support, psychological resilience, and anxiety and depression
The GAD-7 was positively correlated with the PHQ-9 score (r = 0.640, P < 0.01). GAD-7 and PHQ-9 scores were negatively correlated with the PSSS scores, with correlation coefficients of –0.458 and –0.405, and negatively correlated with CD-RISC scores, with correlation coefficients of –0.349 and –0.366, respectively. Finally, perceived social support was positively correlated with psychological resilience (r = 0.312, P < 0.01), as detailed in Table 3.
Table 3.
Correlations between anxiety, depression, psychological resilience, and perceived social support in patients undergoing IVF-ET
| Variables | GAD-7 | PHQ-9 | PSSS | Family support | Friend support | Other support | CD-RISC | Perseverance | Force | Optimism |
|---|---|---|---|---|---|---|---|---|---|---|
| GAD-7 | 1 | - | - | - | - | - | - | - | - | - |
| PHQ-9 | 0.640* | 1 | - | - | - | - | - | - | - | - |
| PSSS | –0.458* | –0.405* | 1 | - | - | - | - | - | - | - |
| Family support | –0.451* | –0.379* | 0.839* | 1 | - | - | - | - | - | - |
| Friend support | –0.381* | –0.335* | 0.891* | 0.604* | 1 | - | - | - | - | - |
| Other support | –0.368* | –0.345* | 0.882* | 0.604* | 0.705* | 1 | - | - | - | - |
| CD-RISC | –0.467* | –0.448* | 0.312* | 0.268* | 0.270* | 0.277* | 1 | - | - | - |
| Perseverance | –0.456* | –0.436* | 0.277* | 0.261* | 0.231* | 0.233* | 0.946* | 1 | - | - |
| Force | –0.423* | –0.395* | 0.271* | 0.214* | 0.245* | 0.248* | 0.905* | 0.771* | 1 | - |
| Optimism | –0.312* | –0.323* | 0.296* | 0.226* | 0.262* | 0.286* | 0.752* | 0.574* | 0.624* | 1 |
*P < 0.01; GAD-7, Generalized anxiety Disorder-7; PHQ-9, Patient Health Questionnaire; PSSS, Perceived Social Support Scale; CD-RISC, Conner-Davidson Resilience Scale
Factors influencing anxiety and depression
Anxiety was used as the dependent variable in a multiple linear regression analysis, educational attainment, place of residence, annual family income, marital status, infertility duration, infertility cause, number of treatments, treatment costs, perceived social support, and psychological resilience as independent variables. Similarly, depression was used as the dependent variable in another multiple linear regression analysis with identical independent variables except for infertility cause, which was not included in the analysis of depression. The model with anxiety as the dependent variable yielded an adjusted R2 of 0.393, an F-statistic of 27.259, and a P-value less than 0.001. Similarly, the model with depression as the dependent variable had an adjusted R2 of 0.374, an F-statistic of 31.670, and a P-value less than 0.001. These results implied that the models satisfactorily fitted the data and were statistically significant. Overall, these findings demonstrated that place of residence, number of treatments, psychological resilience, and levels of perceived social support influenced anxiety in women undergoing IVF-ET(P < 0.05), while annual family income, place of residence, number of treatments, psychological resilience, and levels of perceived social support all influenced depression in women undergoing IVF-ET (P < 0.05), as detailed in Table 4.
Table 4.
Multiple linear regression analysis of the degree of anxiety and depression in women undergoing IVF-ET
| Variables | Beta | P | 95% CI |
|---|---|---|---|
| GAD-7 | |||
| Constant | - | < 0.001 | 14.220 to 18.515 |
| Residence | –0.099 | 0.020 | –1.158 to –0.102 |
| Treatment times | –0.152 | 0.001 | –0.863 to –0.229 |
| Perceived social support | –0.287 | < 0.001 | –0.106 to –0.059 |
| Psychological resilience | –0.333 | < 0.001 | –0.086 to –0.053 |
| PHQ-9 | |||
| Constant | - | < 0.001 | 14.725 to 18.274 |
| Family income | –0.133 | 0.003 | –0.694 to –0.140 |
| Residence | –0.112 | 0.008 | –1.24 to –0.183 |
| Treatment times | –0.163 | < 0.001 | –0.905 to –0.270 |
| Perceived social support | –0.224 | < 0.001 | –0.088 to –0.040 |
| Psychological resilience | –0.332 | < 0.001 | –0.086 to –0.052 |
GAD-7, Generalized anxiety Disorder-7; PHQ-9, Patient Health Questionnaire; PSSS, Perceived Social Support Scale; CD-RISC, Conner-Davidson Resilience Scale
Mediating effect of psychological resilience on the relationship between the level of perceived social support and anxiety and depression
To explore the mechanism underlying the significantly negative impact of the level of perceived social support on anxiety and depression, this study further introduced psychological resilience as a mediating variable into the structural equation model. The mediating effect was examined using Model 4 from the SPSS macro program Process, and the Bootstrap method outlined by Hayes [19] was used to validate the mediating effect of psychological resilience between the level of perceived social support and anxiety and depression. The results, as summarized in Table 5, indicated a total effect coefficient of perceived social support on anxiety of –0.131, with a 95% confidence interval (CI) ranging between –0.156 and –0.110, and a total effect coefficient of perceived social support on depression of –0.116, with a 95% CI between –0.141 and –0.091. Following the introduction of the mediating variable of psychological resilience, the direct effects of perceived social support on anxiety and depression remained significant (P < 0.01), and the indirect effect through psychological resilience was also significant (P < 0.01). This finding signaled that perceived social support can directly predicts anxiety and depression, with psychological resilience playing a partial mediating role between perceived social support and anxiety and depression. The mediating effect of psychological resilience between perceived social support and anxiety accounted for 24.43% of the total effect, while that between perceived social support and depression constituted 27.59%. The path coefficient of psychological resilience between the level of perceived social support and the variables of anxiety and depression is illustrated in Fig. 1.
Table 5.
Analysis of the mediating effect of psychological resilience on the relationship between the level of perceived social support and anxiety and depression
| Path | Effect | Effect size | 95% confidence interval | Proportion of effect | Test conclusion |
|---|---|---|---|---|---|
| PSSS = > CD-RISC = > GAD-7 | Gross effect | –0.131 | –0.156 to –0.110 | 100% | Partial mediation |
| Mesomeric effect | –0.032 | –0.045 to –0.021 | 24.43% | ||
| Direct effect | –0.099 | –0.123 to –0.076 | 75.57% | ||
| PSSS = > CD-RISC = > PHQ-9 | Gross effect | –0.116 | –0.141 to –0.091 | 100% | Partial mediation |
| Mesomeric effect | –0.032 | –0.109 to –0.060 | 27.59% | ||
| Direct effect | –0.084 | –0.044 to –0.022 | 72.41% |
GAD-7, Generalized anxiety Disorder-7; PHQ-9, Patient Health Questionnaire; PSSS, Perceived Social Support Scale; CD-RISC, Conner-Davidson Resilience Scale
Fig. 1.

Mediating model of psychological resilience on the level of perceived social support and anxiety and depression. Note. **P < 0.01; GAD-7, Generalized anxiety Disorder-7; PHQ-9, Patient Health Questionnaire; PSSS, Perceived Social Support Scale; CD-RISC, Conner-Davidson Resilience Scale
Discussion
Current status of perceived social support level, psychological resilience, and anxiety and depression in women undergoing IVF-ET
Perceived social support refers to an individual’s awareness of emotional support and understanding of the external environment. It provides key psychological resources that can effectively restore and replenish the energy consumed by individuals facing life challenges [20]. Furthermore, it can effectively alleviate the impact of negative life events on individuals and concurrently enhance their resilience and self-confidence in dealing with challenges [21]. Herein, the total score for perceived social support level among IVF-ET women was 64.54 ± 10.69, which is higher than the result of Pei et al. [22] in Lanzhou, Gansu Province, China (52.99 ± 9.41). This discrepancy may be ascribed to regional variations among survey subjects. Notably, the level of perceived social support for IVF-ET women may vary based on factors such as economic level, medical resources, openness of social concepts, and government policy support in different regions. Family support usually refers to the support received by individuals from their family members regarding emotional, psychological, material, and practical assistance. The results of this study uncovered that the dimension with the highest item mean score was family support (22.68 ± 3.94), indicating that IVF-ET patients receive more emotional or financial support from their families. This also highlights the need for clinical workers to recognize the role of family support in the mental well-being of women with infertility and effectively leverage this influence to provide targeted education and guidance. Additionally, healthcare professionals should strengthen the construction and optimization of the social support system for IVF-ET female patients, encouraging them to increase communication with family, friends, and others; gain additional outlets for emotional expression; and improve their access to social support. Considering the differences in disease characteristics and mental health levels among patients, the social support network should be expanded. Health education initiatives should be offered to patients to make them feel supported by other members of society beyond their families.
Psychological resilience refers to an individual’s ability to maintain optimism, confidence, and positivity in the face of adversity, stress, and setbacks and demonstrate adaptive solid capabilities to navigate life changes and challenges [23]. The total score of psychological resilience in this study was 64.07 ± 14.73, in line with the results of Wang et al. [24], indicating a moderately low level that is marginally below the international mean [25]. This finding may be attributed to factors such as multiple failed conception attempts, significant physiological and psychological stress, economic burden, and the unpredictable nature of IVF-ET. This finding emphasizes the need for clinical healthcare professionals to impart professional mental health knowledge (such as psychological counseling, emotional education, and stress management skills) and aid in establishing a supportive social network to enhance the level of psychological resilience of infertile women.
Anxiety is defined as a transient emotional experience where individuals feel uncertain about their ability to effectively manage real or imaginary threats, leading to a sense of helplessness and withdrawal [26]. Research suggests that it is a psychological experience that occurs when individuals are confronted with difficult choices and is closely associated with self-consciousness [27]. In contrast, depression is a negative emotional experience characterized by sadness and melancholy and is frequently triggered by stress or negative events [28]. In this study, the average anxiety score for patients was 4.44 ± 3.07, and the average depression score was 4.40 ± 3.07, indicating that these symptoms in participants herein were relatively mild. However, these scores may not be generalizable to all patients undergoing IVF-ET. Given that this sample may have excluded patients with more severe mental health issues, the results may be generalizable to a broader population. Indeed, it is paramount to interpret the results of this study with caution, given that the possibility of selection bias cannot be excluded. Future research should include patients with a wider range of psychological conditions to enhance the generalizability and external validity of these findings. Prior studies evinced that during IVF, the psychological state of patients fluctuates through different stages, with each stage exhibiting distinct characteristics [29]. Negative emotions such as anxiety and depression may elevate the psychological burden of infertile patients, thereby impacting physiological function and treatment outcomes. Thus, psychological support is crucial for alleviating patients’ negative emotions, optimizing treatment compliance, and increasing the success rate [30]. Nonetheless, further studies are warranted to comprehensively analyze changes in the psychological trajectory of women patients undergoing IVF-ET at different stages of treatment and implement targeted and personalized psychological interventions.
Analysis of factors influencing anxiety and depression in women undergoing IVF-ET
Family annual income
Herein, the household annual income significantly affected the levels of depression of patients, with lower annual incomes correlating with higher levels of depression, in agreement with the findings of Hu [31]. This correlation may be attributed to the following reasons: Firstly, during the study period in 2023, assisted reproductive technology in Zhejiang Province was not covered by healthcare insurance, necessitating out-of-pocket payments for IVF-ET. The high medical expenses imposed a significant financial burden on families with lower annual incomes, thereby increasing psychological stress and subsequently triggering depression. Secondly, families with lower annual incomes generally have lower educational attainment, resulting in a lack of understanding of IVF-ET and its treatment process, raising concerns about possible outcomes and increasing uncertainty, which eventually culminate in depression. Additionally, these families may receive less social support and resources, such as assistance from friends and family or access to high-quality medical services. Besides, concerns about the future cost of child-rearing may also induce depression and other negative emotions, thereby increasing the psychological burden. Al-Jadiri et al. [32] identified economic pressure as a significant factor affecting family resilience, suggesting that medical staff should provide patients and their families with information on available economic assistance, medical insurance, and government subsidy policies. This also highlights the need for the government to increase the subsidy level for assisted reproductive technology, expand the coverage of subsidies, and reduce the financial burden on families. Additionally, through measures such as mental health assessments, personalized psychological interventions, the popularization of reproductive health knowledge, and the creation of a favorable medical environment, assistance can be provided to women undergoing IVF-ET, particularly those from families with lower annual incomes, to better cope with depressive emotions.
Residences
The results of this study exposed significant differences in the levels of anxiety and depression among women undergoing in vitro fertilization-embryo transfer (IVF-ET) based on their place of residence, with those residing in rural areas showing higher levels than those in urban areas, consistent with the results of Ma et al. [33]. Of note, these differences may be related to disparities in information access and support systems, as well as cultural and social differences between rural and urban areas. Compared to urban areas, rural areas may have relatively limited transportation networks and medical services, leading to a lack of or delays in access to essential medical resources, information, and social support, which could exacerbate anxiety and depression. Thus, healthcare professionals are recommended to integrate primary healthcare resources and promote mental health services for infertile patients in rural areas by expanding medical services, optimizing reproductive health education, and managing expectations for IVF-ET.
Treatment times
Noteworthily, significant differences were observed in anxiety and depression levels among women undergoing in vitro fertilization-embryo transfer (IVF-ET) across varying numbers of treatment sessions, with the levels being higher in the first-time treatment group compared to the repeat treatment group, inconsistent with the findings of Wang et al. [34]. Potential reasons could be summarized as follows: firstly, women undergoing repeat IVF-ET may have accumulated knowledge and experience about IVF, gained a deeper understanding of the treatment process and potential outcomes, and employed more effective psychological coping mechanisms to address stress and emotional fluctuations during treatment, thus appearing more calm and prepared. Secondly, differences in survey timing, survey tools, and statistical approaches across studies could have contributed to the discrepant results. Lastly, women undergoing repeat treatment might have received more social support from family, friends, or other support groups, which helps alleviate anxiety and depression. Therefore, future research could examine the influence of additional variables (such as treatment stages, individual psychological traits, and social-cultural backgrounds) on the mental health of women undergoing IVF-ET. At the same time, the medical staff should focus on the first-time treatment group, offering targeted psychological support and education to aid these women in managing stress and reducing the risk of anxiety and depression.
Exploration of the relationship between perceived social support, psychological resilience, and anxiety and depression
Multiple linear regression analysis identified perceived social support and psychological resilience as factors influencing anxiety and depression. At the same time, correlation analysis identified a significantly positive correlation between anxiety and depression. Importantly, perceived social support was positively correlated with psychological resilience, consistent with the findings of Yin et al. [35]. Some studies have also indicated that patients with higher levels of perceived social are more likely to experience greater psychological resilience through emotional and material support [35]. This may be due to perceived social support exerting a net beneficial effect on psychological status, helping individuals to accumulate sufficient positive psychological capital [36]. Overall, these results suggest that during infertility treatment, medical staff should pay attention to patients’ perceived social support and implement multiple targeted measures to improve the level of perceived social support among patients undergoing IVF-ET. When patients perceive a high level of quality in their perceived social support, it can effectively stimulate positive emotions and mobilize internal resources, enhancing their ability to cope with fertility issues, which can mitigate infertility-related adverse effects.
Anxiety and depression were negatively correlated with both psychological resilience and perceived social support. Specifically, perceived social support was moderately negatively correlated with anxiety and depression, suggesting that while social support is a key protective factor for women undergoing IVF-ET, it may not be the sole factor affecting the levels of anxiety and depression. Related studies have identified individual age, duration and type of infertility, infertility factors, treatment duration, educational attainment, occupation, economic status, social support, and coping mechanisms as primary factors influencing anxiety and depression during assisted reproductive treatment [37]. However, it is worthwhile recognizing that the design of this study did not allow a comprehensive exploration of all possible variables and complex interactions.
A study conducted by Carvalho et al. [38] showed that patients with higher psychological resilience are more likely to be more confident in overcoming the disease, resulting in lower levels of anxiety and depression. In the current study, psychological resilience was moderately negatively correlated with anxiety and depression, indicating that individuals with higher psychological resilience are more able to maintain a positive attitude towards stress or adversity, thereby lowering the risk of anxiety and depression. This also highlights the importance of enhancing the level of psychological resilience in mental health interventions for women undergoing IVF-ET. Furthermore, a correlation analysis was conducted to examine relationships between the three dimensions of psychological resilience (tenacity, strength, and optimism), as well as between the three dimensions of perceived social support (family support, friend support, and other support) and anxiety and depression. The results demonstrated that both the source of psychological resilience and the level of perceived social support partially influenced the anxiety and depression levels of patients. This provides potential targets for subsequent health education intervention research. Subsequent studies on the negative emotions of women undergoing IVF-ET could explore the level of perceived social support and psychological resilience from multiple perspectives to assist individuals in better coping with various challenges and promoting fertility welfare. In addition, clinical medical staff is recommended to actively leverage various social resources available to patients, encourage family members and friends to strengthen communication, and address the patients’ economic and emotional needs in order to improve their level of perceived social support. Moreover, interventions such as cognitive therapy, group psychological counseling, and mindfulness therapy should be reasonably implemented to reduce the patient’s excessive focus on infertility, alleviate their psychological stress, enhance their confidence in actively coping with the disease, and improve their level of psychological resilience.
Mediating effect of psychological resilience
The results of the mediational effect analysis suggested that psychological resilience partially mediated the relationship between perceived social support with anxiety and depression. In line with the findings of Zhang [39], this study found that among women with infertility, psychological resilience acted as a mediating factor between perceived social support, anxiety, and depression [40]. This study further validated that this mediating effect remained significant in women undergoing IVF-ET. Perceived social support can indirectly affect anxiety and depression through psychological resilience, signifying that patients with higher levels of perceived support also have higher levels of psychological resilience and lower levels of anxiety and depression. Hence, psychological resilience could partially account for the association between perceived social support, anxiety, and depression, suggesting that it may influence individual perception and use of social support, which in turn affects mental health. Earlier studies have pointed out that the level of perceived social support predicts psychological resilience, suggesting that increased perception of social support could enhance psychological resilience [40]. As a psychological trait, psychological resilience can promote an individual’s adaptive capacity when facing stress and challenges, helping them effectively utilize social support from family, friends, or other sources. Therefore, healthcare workers are recommended to assess patients’ levels of psychological resilience and perceived social support when formulating mental health intervention measures to minimize the risk of anxiety and depression and improve fertility outcomes.
Limitations
Nevertheless, this study has several limitations that merit acknowledgment. To begin, the study employed convenience sampling, recruiting IVF-ET infertile women from a single hospital in Zhejiang Province, which may have inherently introduced sample selection bias. Our results warrant validation with a more representative sample size from multiple centers across different regions of China in future studies. Secondly, this study exclusively investigated the perceived social support, anxiety, depression, and psychological resilience of IVF-ET women, which may significantly differ from infertile men. Future research should consider exploring gender differences by including both infertile men and women. Thirdly, our sample consisted of women who had already received treatment; IVF-ET women who have undergone treatment might exhibit lower perceived social support and psychological resilience compared to those who have never sought treatment, which deserves further investigation in future studies. Finally, the cross-sectional research design of this study restricted our ability to establish causal relationships between perceived social support, anxiety, depression, and related factors. Thus, future longitudinal research designs are required to validate these potential associations.
Acknowledgements
The completion of this research would not have been possible without the support and assistance from numerous individuals and organizations. Firstly, my sincere thanks and appreciations to Chief Nurse Lanfeng Xing, whose suggestions and encouragement have given me much insight into these studies. Secondly, I am thankful for the language editing services provided by the Home for Researchers editorial team (www.home-for-researchers.com). Lastly, I want to thank my family and friends for their understanding, support, and encouragement, which have enabled me to overcome the difficulties encountered in the research process and successfully complete this work.
Author contribution
Yuying Yan and Ya Ma contributed equally to this work.
Funding
This work was supported by the Medical Science and Technology Project of Zhejiang Province (Number: 2024KY1154).
Data availability
The authors will supply the relevant data in response to reasonable requests.
Code availability
The research data of this study is exclusively licensed to Springer Science. Please cite this paper when using it.
Declarations
Ethics approval
This study was approved by the Ethics Committee of the Affiliated Obstetrics and Gynecology of Women’s Hospital School of Medicine Zhejiang University (IRB-20200025-R).
Consent to participate
Informed consent was obtained from all individual participants included in the study.
Consent for publication
Not applicable.
Competing interests
The authors declare no competing interests.
Footnotes
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
References
- 1.Koochaksaraei FY, Simbar M, Khoshnoodifar M, Faramarzi M, Nasiri M. Interventions promoting mental health dimensions in infertile women: a systematic review. BMC Psychol. 2023;11:254. 10.1186/s40359-023-01285-1. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Abulizi M, Xu H, Abuduguli A, Zhao W, He L, Zhang C. Dual mediating effects of social support and fertility stress on mindfulness and fertility quality of life in infertile men: a case-control study. Front Psychol. 2023;14:1138282. 10.3389/fpsyg.2023.1138282. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.Liu Y, Deng Y, Liu L, Shen J, Zhang L, Wang X. A Study on the relationship between fertility pressure, perceived partner responsive-ness and family resilience in female infertility patients and their spouses. J Nurs Sci. 2024;39:1–5. [Google Scholar]
- 4.Ying LY, Wu LH, Loke AY. Gender differences in experiences with and adjustments to infertility: a literature review. Int J Nurs Stud. 2015;52:1640–52. 10.1016/j.ijnurstu.2015.05.004. [DOI] [PubMed] [Google Scholar]
- 5.Zhou Y, Sun Z, Song J. Research progress on the impact of anxiety and depression on embryo transfer outcomes of in vitro fertilization. Zhejiang Da Xue Xue Bao Yi Xue Ban. 2023;52:61–7. 10.3724/zdxbyxb-2022-0473. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.Wang L, Tang Y, Wang Y. Predictors and incidence of depression and anxiety in women undergoing infertility treatment: a cross-sectional study. PLoS ONE. 2023;18:e0284414. 10.1371/journal.pone.0284414. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7.Zhang F, Zhu S, Deng P. Evaluation of Perceived Social Support Scale used in study of social support among hospitalized patients in China. Chin Nurs Res. 2018;32:2048–52. 10.12102/j.issn.1009-6493.2018.13.015. [Google Scholar]
- 8.Jamilian H, Jamilian M, Soltany S. The comparison of quality of life and social support among fertile and infertile women. J Patient Saf Qual Improv. 2017;5:521–5. [Google Scholar]
- 9.Liu Y, Zhu J, Zhao J, Tian Y. Relationships of family function and social support with mental health of infertile women. Chinese Journal of Women and Child Health Research. 2022;33(5):14–9. 10.3969/j.issn.1673-5293.2022.05.003. [Google Scholar]
- 10.Lei A, You H, Luo B, Ren J. The associations between infertility-related stress, family adaptability and family cohesion in infertile couples. Sci Rep. 2021;11:24220. 10.1038/s41598-021-03715-9. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.Zhang X, Deng X, Mo Y, Li Y, Song X, Li H. Relationship between infertility-related stress and resilience with posttraumatic growth in infertile couples: gender differences and dyadic interaction. Hum Reprod. 2021;36:1862–70. 10.1093/humrep/deab096. [DOI] [PubMed] [Google Scholar]
- 12.Huang Y, Wu R, Wu J, Yang Q, Zheng S, Wu K. Psychological resilience, self-acceptance, perceived social support and their associations with mental health of incarcerated offenders in China. Asian J Psychiatr. 2020;52:102166. 10.1016/j.ajp.2020.102166. [DOI] [PubMed] [Google Scholar]
- 13.Li Y, Zhang X, Shi M, Guo S, Wang L. Resilience acts as a moderator in the relationship between infertility-related stress and fertility quality of life among women with infertility: a cross-sectional study. Health Qual Life Outcomes. 2019;17(1):38. 10.1186/s12955-019-1099-8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Zimet GD, Powell SS, Farley GK, Werkman S, Berkoff KA. Psychometric characteristics of the multidimensional scale of perceived social support. J Pers Assess. 1990;55:610–7. 10.1080/00223891.1990.9674095. [DOI] [PubMed] [Google Scholar]
- 15.Jiang QJ. Perceived social support scale. Chin J Behav Med Sci. 2001;10(10):41–3. [Google Scholar]
- 16.Connor KM, Davidson JR. Development of a new resilience scale: the Connor-Davidson Resilience Scale (CD-RISC). Depress Anxiety. 2003;18:76–82. 10.1002/da.10113. [DOI] [PubMed] [Google Scholar]
- 17.Spitzer RL, Kroenke K, Williams JB, Löwe B. A brief measure for assessing generalized anxiety disorder: the GAD-7. Arch Intern Med. 2006;166:1092–7. 10.1001/archinte.166.10.1092. [DOI] [PubMed] [Google Scholar]
- 18.Kroenke K, Spitzer RL, Williams JB. The PHQ-9: validity of a brief depression severity measure. J Gen Intern Med. 2001;16:606–13. 10.1046/j.1525-1497.2001.016009606.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 19.Hayes AF. PROCESS: a versatile computational tool for observed variable mediation, moderation, and conditional process modeling. Behav Res Methods. 2012;6.
- 20.Ong HL, Vaingankar JA, Abdin E, Sambasivam R, Fauziana R, Tan ME, Chong SA, Goveas RR, Chiam PC, Subramaniam M. Resilience and burden in caregivers of older adults: moderating and mediating effects of perceived social support. BMC Psychiatry. 2018;18:27. 10.1186/s12888-018-1616-z. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 21.Zhang J, Yin Y, Wang A, Li H, Li J, Yang S, Wu Y, Zhang J. Resilience in patients with lung cancer: structural equation modeling. Cancer Nurs. 2021;44:465–72. 10.1097/ncc.0000000000000838. [DOI] [PubMed] [Google Scholar]
- 22.Pei M, Xie L, Liu H, Ma X, Li S, Hu J. Status quo of distress disclosure among infertile patients and its influencing factors. Nurs J Chin People’s Lib Army. 2022;39:9–12. [Google Scholar]
- 23.Ayed N, Toner S, Priebe S. Conceptualizing resilience in adult mental health literature: a systematic review and narrative synthesis. Psychol Psychother. 2019;92:299–341. 10.1111/papt.12185. [DOI] [PubMed] [Google Scholar]
- 24.Wang DH, Zhao Q, Liao J, Guo JB, Shao J, Hu JP. Effect of psychological resilience and perceived social support on post-traumatic growth in patients undergoing IVF-ET. J Reprod Med. 2021;30:1445–9. [Google Scholar]
- 25.Campbell-Sills L, Stein MB. Psychometric analysis and refinement of the Connor-Davidson Resilience Scale (CD-RISC): validation of a 10-item measure of resilience. J Trauma Stress. 2007;20:1019–28. 10.1002/jts.20271. [DOI] [PubMed] [Google Scholar]
- 26.Xu X, Wang S, Pan X. Relationship between anxiety emotions and personality traits of primary caregivers of senile dementia patients: mediating effect of psychological resilience. China J Health Psychol. 2024;32:1141–6. [Google Scholar]
- 27.Konstantopoulou G, Iliou T, Karaivazoglou K, Iconomou G, Assimakopoulos K, Alexopoulos P. Associations between (sub) clinical stress- and anxiety symptoms in mentally healthy individuals and in major depression: a cross-sectional clinical study. BMC Psychiatry. 2020;20:428. 10.1186/s12888-020-02836-1. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 28.Zhao Q. The relationship between negative life events and depression of senior high school students: the moderation of resilience and educational intervention. Chengdu University; 2024. p 22.
- 29.Maroufizadeh S, Hosseini M, Foroushani AR, Omani-Samani R, Amini P. Application of the dyadic data analysis in behavioral medicine research: marital satisfaction and anxiety in infertile couples. BMC Med Res Methodol. 2018;18:117. 10.1186/s12874-018-0582-y. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 30.Ju Q, Xu L. Clinical curative effect of hysteroscopy-laparoscopy combined with supportive psychotherapy in the treatment of oviduct obstructive infertility and the influence onanxiety, depression, coping style and quality of life. China J Health Psychol. 2019;27:523–7. [Google Scholar]
- 31.Hu M. Analysis of related factors of depression and anxiety in female infertility patients. Qingdao University; 2018. p 18.
- 32.Al-Jadiri A, Tybor DJ, Mulé C, Sakai C. Factors associated with resilience in families of children with autism spectrum disorder. J Dev Behav Pediatr. 2021;42:16–22. 10.1097/dbp.0000000000000867. [DOI] [PubMed] [Google Scholar]
- 33.Ma D, Bai C, Mao X, Cao F. Relation of emotion regulation strategies to depression and anxiety symptoms in infertile patients. Chin Ment Health J. 2023;37:662–71. [Google Scholar]
- 34.Wang W, Yang F, Bai Y, Lu Y, Mao X. Association between domain-specific physical activity and mental health status after embryo transfer in IVF-ET-assisted pregnancy patients. Sci Rep. 2024;14:4928. 10.1038/s41598-024-55097-3. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 35.Yin Y, Lyu M, Chen Y, Zhang J, Li H, Li H, Xia G, Zhang J. Self-efficacy and positive coping mediate the relationship between social support and resilience in patients undergoing lung cancer treatment: a cross-sectional study. Front Psychol. 2022;13:953491. 10.3389/fpsyg.2022.953491. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 36.Sun Z, Lai L. Effect of social support on health-promoting behavior of floating elderly people-the mediating role of self-efficacy. Soft Sci Health. 2023;37:37–42. [Google Scholar]
- 37.Dai K, Li R, Zheng L, Li Y, Li D, Wang W. Evaluation of factors associated with the anxiety and depression of infertility patients and the effect on in vitro fertilization outcomes. Chin J Reprod Contracept. 2018;18(7). 10.3760/cma.j.issn.2096-2916.2018.07.010.
- 38.Carvalho IG, Bertolli ED, Paiva L, Rossi LA, Dantas RA, Pompeo DA. Anxiety, depression, resilience and self-esteem in individuals with cardiovascular diseases. Rev Lat Am Enfermagem. 2016;24:e2836. 10.1590/1518-8345.1405.2836. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 39.Zhang X. The relationship between fertility stress, social support and depressive symptoms in female infertility patients: the mediating role of psychological resilience. China Medical University; 2020. p 26.
- 40.Ristevska-Dimitrovska G, Filov I, Rajchanovska D, Stefanovski P, Dejanova B. Resilience and quality of life in breast cancer patients. Open Access Maced J Med Sci. 2015;3:727–31. 10.3889/oamjms.2015.128. [DOI] [PMC free article] [PubMed] [Google Scholar]
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Data Availability Statement
The authors will supply the relevant data in response to reasonable requests.
The research data of this study is exclusively licensed to Springer Science. Please cite this paper when using it.
