1. Introduction
estational diabetes is the most prevalent metabolic disorder in pregnancy [1]. The adherence of diabetic patients to the recommended treatment regimens is among the major challenges in diabetes control [6]. The acceptance of physicians’ recommendations, including medication, diet, and exercise, and adherence to it leads to the control of the patient’s blood glucose; it also plays a decisive role in predicting complications associated with diabetes [8]. Studies reported that following medication and care instructions (diet, blood glucose monitoring, & exercise) is insufficient [9]. Failure to follow can reduce the beneficial therapeutic effects, signs, and symptoms, increase complications, or even cause death. Therefore, further research on the determinants of adherence to treatment regimens seems necessary [11]. Previous studies revealed that some individual and social characteristics can affect the rate of adherence to the treatment regimen [13]. Therefore, the present study aimed to determine the relationship between demographic characteristics and pregnancy, and adherence to treatment in patients with gestational diabetes.
2. Materials and Methods
 This descriptive-analytical study was conducted in 2019. The study subjects were 260 women with gestational diabetes treated with diet referring to healthcare centers and hospitals of Imam Reza, Ghaem, Umm Al-Banin. The study participants were selected by multistage integration sampling method in Mashhad City, Iran. The necessary data were collected using a demographic and pregnancy information checklist and a researcher-made questionnaire on adherence to treatment. The obtained demographic and pregnancy information included age; education; occupation; monthly income; gestational diabetes information; history of diabetes in first-degree relatives; history of gestational diabetes; the number of pregnancies; history of miscarriage; stillbirth and infertility, and whether or not the pregnancy was desired. To measure adherence to diet, exercise, and blood glucose monitoring, a researcher-made questionnaire was used; it includes 17 questions answered on a Likert-type scale. Moreover, 12 questions are related to diet, 2 questions concern exercise and 3 questions address blood glucose monitoring (it included two parts of self-monitoring & venous blood glucose monitoring). The validity of the tools was determined using the Content Validity Index (CVI). The validity of the researcher-made adherence to treatment questionnaire was measured by a CVI of 0.97 and a Content Validity Ratio (CVR) of 0.89. The reliability of the questionnaire of diet adherence, blood glucose monitoring, and exercise was determined using Cronbach’s alpha coefficient of 0.83. Data analysis was performed in SPSS by the statistical indices of mean, standard deviation, frequency distribution, and multiple linear regression.
3. Results  
The frequency distribution of women with gestational diabetes respecting demographic and fertility characteristics is presented in Table 1.


The scores of adherence to the treatment regimen and its components in women with gestational diabetes are illustrated in Table 2.


The regression analysis results of all demographic and pregnancy variables with the total score of treatment adherence reflected that diet adherence, blood glucose monitoring, and exercise adherence scores provided a significant and positive correlation with total treatment adherence score (P<0.001). According to the standardized coefficient values, diet compliance, blood glucose monitoring, and exercise adherence scores presented the greatest correlation with the total treatment adherence score, respectively. The obtained results also signified that individuals with university education had a higher total score of treatment adherence, compared to the subjects with reading and writing education (P=0.044). Unwanted (P=0.006) or unplanned (P=0.021) pregnancies were positively and significantly correlated with the total score of treatment adherence. Women with a history of first-degree diabetes (P=0.010) and women with a history of abortion (P=0.021) achieved higher scores of total treatment adherence. In other variables, there was no significant correlation with the total score of treatment adherence (Table 3).


4. Discussion and Conclusion
The present study results revealed that adherence to diet score, blood glucose monitoring score, and adherence to exercise score presented a significant and positive relationship with the total treatment adherence score. Hernández-Ronquillo et al. (2003) also documented that patients who followed the instructions related to physical activity and exercise were successful in controlling diabetes [17]. Furthermore, the obtained data signified a positive and significant correlation between the level of education and the total score of adherence to the treatment regimen. According to Abedi et al. (2015), there was a significant and positive association between following the treatment regimen of type 2 diabetes and education [16]. In the present study, no significant relationship was found between the extent of information (according to the subject) about gestational diabetes and the score of treatment adherence. In the study of Haji Arabi et al. (2018), no significant relationship was found between knowledge about diabetes and self-care in patients with gestational diabetes [20]. In the present study, unwanted or unplanned pregnancies were positively and significantly correlated with the total score of treatment adherence. Farahani Dastjani et al. (2015) observed an inverse relationship and a significant difference between the lack of motivation and adherence to pharmacotherapy [22]. In the present study, women with a history of miscarriage presented a higher adherence to treatment. Women with an abortion experience (an abortion caused by gestational diabetes or any other reasons) and those who have lost their fetus seem to care more about their treatment regimen and manifest greater adherence to treatment. 
The current research results suggested that some demographic and pregnancy characteristics were associated with adherence to treatment in women with gestational diabetes; thus, healthcare providers, especially midwives and gynecologists must improve adherence to treatment by considering the role of these factors in these patients. 

Ethical Considerations
Compliance with ethical guidelines
This study was approved by the Ethics Committee of Mashhad University of Medical Sciences (Code: IR.MUMS.NURSE.REC.1397.091).

Funding
This research was supported by the Vice-Chancellor for Research, School of Nursing and Midwifery, Mashhad University of Medical Sciences (Grant No.: 971109).

Authors' contributions
Conceptualization: Maryam Moradi, Zahra Abedian; Research and sampling method: Mahla Salarfard, Ehsan Musa Farkhani; Data analysis: Mahla Salarfard, Seyed Reza Mazloum and Maryam Moradi; Text Writing and Review: All Authors.

Conflicts of interest
The authors declared no conflicts of interest.

Acknowledgements
We would like to thank the Student Research Committee of Mashhad University of Medical Sciences and the director and staff of Emma Reza, Ghaem, and Umm Al-Banin hospitals, and healthcare centers in Mashhad who contributed to this research.


References

1. Cunningham FG, Leveno KJ, Bloom SL, Dashe JS, Hoffman BL, Casey BM, et al. Williams Obstetrics. New York City: McGraw-Hill Education; 2018. https://books.google.com/books?id=mhOdAQAACAAJ&dq=Williams+Obstetrics,+25e&hl=en&sa=X&ved=2ahUKEwjJ-_vx5unxAhUBCxoKHVZjDCoQ6AEwAHoECAsQAg
2. Jamilian M, Afshar R. [Effects of combined evening primrose oil and vitamin D intake on hs-CRP, oxidative stress and pregnancy outcomes in women with gestational diabetes (Persian)]. J Arak Univ Med Sci. 2017; 19(12):43-51. http://jams.arakmu.ac.ir/article-1-4736-en.html
3. Hunt KJ, Schuller KL. The increasing prevalence of diabetes in pregnancy. Obstet Gynecol Clin North Am. 2007; 34.(2):173-99. [DOI:10.1016/j.ogc.2007.03.002.] [PMID] [PMCID]
4. Jafari-Shobeiri M, Ghojazadeh M, Azami-Aghdash S, Naghavi-Behzad M, Piri R, Pourali-Akbar Y, Nasrollah-Zadeh R, et al. Prevalence and risk factors of gestational diabetes in Iran: A systematic review and meta-analysis. Iran J Public Health. 2015; 44(8):1036-44. [PMID] [PMCID]
5. Salzer L, Yogev Y. Complications of gestational diabetes. In: Petry CJ, editor. Gestational diabetes: Origins, complications, and treatment. Florida: CRC Press; 2014. p.95. [DOI:10.1201/b16474-9]
6. Kooshyar H, Shoorvazi M, Dalir Z, Hosseini M. [Health literacy and its relationship with medical adherence and health-related quality of life in diabetic community-residing elderly (Persian)]. J Mazandaran Univ Med Sci. 2014; 23(1):134-43. http://jmums.mazums.ac.ir/article-1-3439-en.html
7. Osterberg L, Blaschke T. Adherence to medication. N Engl J Med. 2005; 353(5):487-97.[DOI:10.1056/NEJMra050100] [PMID]
8. Shrivastava SR, Shrivastava PS, Ramasamy J. Role of self-care in management of diabetes mellitus. J Diabetes Metab Disord. 2013; 12(1):14. [DOI:10.1186/2251-6581-12-14.] [PMID] [PMCID]
9. Rezaie Kargar F, Karbandi S, Hassanabadi H, Esmaili H. [Type of Personality and the Amount of Adherence to Recommended Regimens in Diabetic Patients (Persian)]. Psychiatry Clin Psychol Iran. 2006; 11(4):441-8. http://ijpcp.iums.ac.ir/article-1-50-fa.html
10. Karimi S, Mansouri P, shahdadi H, Pakizedel P. [The effect of health belief model-based education on adherence to the dietary regimen in pregnant women with gestational diabetes (Persian)]. J Diabetes Nurs. 2016; 4(4):1-9. http://jdn.zbmu.ac.ir/article-1-216-fa.html
11. Rouhi Balasi l, Paryad E, Kazemnezhad Leili E, Booraki SH, SadeghiMeibodi A, Nassiri Sheikhani N. [Study status of care adherence and its related factors in patients undergoing (Persian)]. J Holist Nurs Midwifery. 2015; 25(3):34-45. http://hnmj.gums.ac.ir/article-1-525-en.html
12. Bosworth HB, Oddone EZ, Weinberger M. Patient treatment adherence: Concepts, interventions, and measurement. New York: Psychology Press; 2006. [DOI:10.4324/9781410615626]
13. Lerman I. Adherence to treatment: The key for avoiding long-term complications of diabetes. Arch Med Res. 2005; 36(3):300-6. [DOI:10.1016/j.arcmed.2004.12.001.] [PMID]
14. hashemi M, haghighat S, bagheri M, Akbari M, Niknejad R.[Factors affecting adherence to the treatment in patients under hemodialysis: A qualitative content analysis (Persian)]. Nurs Midwifery J. 2020; 18(2):141-56. http://unmf.umsu.ac.ir/article-1-3899-en.html
15. Browne T, Merighi JR. Barriers to adult hemodialysis patients’ self-management of oral medications. Am J Kidney Dis. 2010; 56(3):547-57. [DOI:10.1053/j.ajkd.2010.03.002.] [PMID]
16. Abedi H, Rezayi A, Alimohammadi N, GhodusiA, Maghroun A. [An investigation of demographic and social factors affecting compliance with therapeutic regimens in type 2 diabetic patients (Persian)]. J Diabetes Nurs. 2015; 3(2):66-81. http://jdn.zbmu.ac.ir/article-1-116-fa.html
17. Hernández-Ronquillo L, Téllez-Zenteno JF, Garduño-Espinosa J, González-Acevez E. Factors associated with therapy noncompliance in type-2 diabetes patients. Salud Publica Mex. 2003; 45(3):191-7. [DOI:10.1590/S0036-36342003000300008] [PMID]
18. Sweileh WM, Aker O, Hamooz S. Rate of compliance among patients with diabetes mellitus and hypertension. An-Najah Univ J Res. 2005; 19(1). https://repository.najah.edu/bitstream/handle/20.500.11888/1860/rate-compliance-among-patients-diabetes-mellitus-and-hypertension.pdf?sequence=1&isAllowed=y
19. Nouri A. [Investigating the socio-economic factors affecting the compliance of patients with gestational diabetes with the doctor’s instructions in the clients of Kerman Diabetes Center in 2013 (Persian)] [MS. thesis]. Kerman: Kerman University of Medical Sciences; 2015. http://eprints.kmu.ac.ir/id/eprint/21727
20. Haji-Arabi E, Nobahar M, Ghorbani R. [Relationship between depression and knowledge about diabetes with the amount of self-care in patients with type 2 diabetes (Persian)]. Koomesh. 2018; 20(2):210-20. http://koomeshjournal.semums.ac.ir/article-1-4164-fa.html.
21. Haque M, Emerson SH, Dennison CR, Navsa M, Levitt NS. Barriers to initiating insulin therapy in patients with type 2 diabetes mellitus in public-sector primary health care centres in Cape Town. S Afr Med J. 2005; 95(10):798-802. [PMID]
22. Farahani Dastjani F, Shamsi M, Khorsandi M, Rezanfar RMZ. [Investigating the relationship between the barriers and non-compliance with the drug regimen in type 2 diabetic patients in Arak in 2014 (Persian)]. Daneshvar Med. 2015; 23(2):49-58. https://www.sid.ir/fa/journal/ViewPaper.aspx?id=246071
23. Sweeting AN, Appelblom H, Ross GP, Wong J, Kouru H, Williams PF, et al. First trimester prediction of gestational diabetes mellitus: A clinical model based on maternal demographic parameters. Diabetes Res Clin Pract. 2017; 127:44-50. [DOI:10.1016/j.diabres.2017.02.036] [PMID]