Although pregnancy is a normal physiologic phenomenon, it can deviate from its normal path and cause disability, or even maternal and fetal mortality ¹ . Gestational diabetes is a major disorder that causes numerous complications in the mother and her baby. Gestational diabetes is a metabolic disorder that emerges or is diagnosed for the first time with carbohydrate intolerance during pregnancy and is considered the most common gestational complication ² . The prevalence of gestational diabetes differs in different regions, which can be explained by factors, such as ethnic diversity, differences in lifestyle and nutrition and different screening protocols ³ . This disease influences maternal and fetal health and causes the emergence of numerous undesirable outcomes ⁴ . These complications include hypertension, preeclampsia, urinary tract infections, hydramnios, surgical interventions, the risk of developing type 2 diabetes in mothers in the future, and macrosomia followed by an increased risk of birth trauma, congenital anomalies, childhood obesity and growth disorders in neonates ⁵ .

Many factors are associated with gestational diabetes, including social determinants of health ⁶ . Lifestyle is one of the main factors that can play a key role in preventing or treating gestational diabetes. Research suggests serious relationships between developing diabetes and lifestyle risk factors, such as smoking, inappropriate nutrition, drinking, obesity and limited physical activity ^{7, 8} . Nowadays, more than 70% of diseases are believed to be somewhat related to people’s lifestyle and many illnesses appear to be directly or indirectly caused by lifestyle or at least be exacerbated or sustained by lifestyle ^{9, 10} . Gestational diabetes prevention strategies have recently focused on promoting healthy lifestyles in patients by encouraging physical activity and promoting healthy nutrition ¹¹ . Nevertheless, modifying lifestyle requires adequate information in this regard ¹² . In fact, the decisions made by people and their performance regarding lifestyle behaviors depends on their level of literacy, which exerts a key effect on preventing and controlling chronic diseases such as diabetes ¹³ . Today, health literacy improves health behaviors, creates a healthy lifestyle and promotes the quality of life ^{14– 16} . Health literacy refers to one’s capacity for acquiring, interpreting and understanding primary health information and services required for proper health decision making ¹⁷ . Enhancing the awareness and preparedness during pregnancy helps the mother pass this stage of life with fewer complications. As a result, pregnancy provides a good opportunity for teaching and counseling pregnant women and making them aware of the advantages of having a healthy lifestyle ¹⁸ . Given the importance of pregnant women as a vulnerable social class, the fifth goal of United Nations Millennium Development Goals, i.e. a 75% reduction in maternal mortality through improving mothers’ health ¹⁹ , and the significance of gestational diabetes as the most common pregnancy complication and a threat to the mother’s and baby’s health, the present study was performed to examine the effect of a health literacy approach to counselling on the lifestyle of women with high-risk pregnancy and gestational diabetes.

The present randomized controlled clinical trial was conducted using a parallel design. The study population comprised pregnant women with gestational diabetes presenting to Alborz and Kamali hospitals in Karaj, Iran in April 2017.

The present research was approved by the Ethics Committee of Alborz University of Medical Sciences and Health Services on 4 March 2017 (Abzums.Rec.1395.146), and registered in the Iranian Registry of Clinical Trials ( IRCT2017021427728N3) on 5 ^th April 2017. A completed CONSORT checklist can be found in Supplementary File 1.

Inclusion criteria: The eligible candidates comprised 18–35-year-old Iranian women with gestational diabetes, whose disease was first diagnosed using the FBS, OGTT or GCT tests, as per the criteria of the World Health Organization ²⁰ . The exclusion criteria consisted of being absent from, at most, two counseling sessions, having other physical or mental co-morbidities, such as cardiac, renal and thyroid disorders, and unwillingness to participate in the study.

After going to prenatal clinics of Alborz and Kamali Hospitals for routine check-ups, the researcher (MG) identified eligible mothers and explained the study objectives to them and asked them to sign an informed consent form if they were willing to participate. Convenience sampling was first used to select the subjects. They were then assigned to the intervention and control groups based on randomized blocks of four. Each “block” had a specified number of randomly ordered treatment assignments.

A total of 100 subjects were initially recruited, and 16 were excluded during the study: 8 subjects were excluded in the intervention group, including 2 for failing to complete the questionnaires, 4 for being absent for more than two sessions, and 2 for preterm delivery at a 25-week and 29-week gestational age; 8 subjects were also excluded from the control group, including 4 for failing to complete the questionnaires, 3 for failing to attend the sessions and 1 for abortion at 16 weeks of pregnancy. Therefore, the study ended with 84 subjects ( Figure 1).

The present study investigated 84 mothers with gestational diabetes in two groups, who were examined until the end of the study. After examining the normality of the study variables, no significant differences were observed between the two groups in terms of mean age, level of education, body mass index (BMI), occupational status and gestational age, and the two groups were therefore matched in terms of the cited variables ( Table 1).

According to the study findings, no significant differences were observed between the two groups in terms of the mean score of lifestyle before the intervention. Therefore, the two groups were matched before the intervention in terms of lifestyle. The two groups exhibited significant differences in the mean score of lifestyle after the intervention. This mean score showed a significant increase immediately and three weeks after the intervention, and this increase was higher in the intervention group ( Table 2).

No significant differences were observed between the two groups in terms of the mean score of health literacy before the intervention, and the two groups were therefore matched in this regard. The two groups exhibited significant differences in the mean score of health literacy immediately and three weeks after the intervention, and this increase was significant in the intervention group ( Table 3).

Gestational diabetes is a common disorder during pregnancy, which can negatively affect prenatal outcomes and is associated with lifestyle risk factors. Modern prevention methods of gestational diabetes emphasize modifying lifestyle risk factors ^{18, 22} .

The present study findings suggest no significant differences between the two groups before counselling in terms of the score of lifestyle. In other words, the two groups presented the same level of lifestyle upon entering the study; however, immediately after and three weeks after the intervention, a higher increase was observed in the mean scores of variables, such as physical health, sports and fitness, weight management and nutrition, disease prevention, mental health, avoidance of drugs, alcohol and opiates, accident prevention and the overall lifestyle of the mothers, in the intervention group compared to those in the control group, although no significant differences were observed between the two groups in spiritual health and environmental health.

In 2011, Luoto et al. found that interventions such as counselling can improve lifestyle quality in pregnant patients at risk of developing gestational diabetes ²³ . Numerous studies have explained the effect of interventions on modifying lifestyle, and their results are consistent with those obtained in the present study. In 2015, Khadivzadeh et al. found that educational lifestyle interventions can help promote self-care in patients with gestational diabetes ²⁴ . Babaei et al. (2016) ²⁵ and Korpi-Hyövälti et al. (2012) reported that individual counseling conducted by experts as part of lifestyle interventions modifies nutrition and sports dimensions of lifestyle ^{26, 27} . A study conducted by Babei et al. titled “the effect of educational intervention of lifestyle modification on blood pressure control in patients with hypertension” showed that educational programs can modify and increase the score of lifestyle dimensions, including sports and fitness, weight management and nutrition and mental health, although these interventions were found not to affect spiritual health ²⁵ .

Before the intervention, no significant differences were observed between the two groups in the score of health literacy, and the two groups were matched in terms of the level of health literacy. The mean score of health literacy, however, showed a higher increase immediately and three weeks after the intervention in the intervention group compared to that in the controls. Given that the two groups were matched in terms of demographic characteristics and level of health literacy, the findings suggest the effect and role of counseling and the counselor midwife in improving the level of health literacy in mothers with gestational diabetes. This finding is consistent with the results of the studies conducted by Tol et al. ²⁸ and Kandula et al. ²⁹ . These researchers found that education and counselling increase the score of health literacy in diabetics with any levels of health literacy. Luoto et al. reported that interventions at the level of patient communication skills can improve the awareness, literacy and clinical indicators of diabetics ²³ . Today, many health problems and human social needs can be solved using advisors as facilitators for knowledge based on useful relationships. ³⁰ .

The strength of the present study was the fact that the intervention and control groups matched in terms of some confounding demographic variables affecting the results, including age, level of education, BMI and gestational age, and the results obtained were not therefore affected by these variables. The researchers made efforts to use random allocation and match the subjects in both groups; however, the subjects’ lifestyle was impossible to be completely controlled and this was a limitation of the present research.

The findings obtained from the present research showed that both routine pregnancy counselling and a health literacy approach to counselling causes an increase in the overall score of lifestyle and health literacy. As members of the health system and the main supervisors of pregnant women, midwives have the closest relationship with these women and are in charge of providing them with care services and necessary recommendations during pregnancy. They can therefore take more effective steps towards improving mothers’ health and pregnancy outcomes by applying correct counselling principles for resolving mothers’ problems.

The present research was approved by the Ethics Committee of Alborz University of Medical Sciences and Health Services on 4 March 2017 (Abzums.Rec.1395.146). Written informed consent was obtained from all subjects for participation in the study.

The data referenced by this article are under copyright with the following copyright statement: Copyright: � 2018 Gharachourlo M et al.

Data associated with the article are available under the terms of the Creative Commons Zero "No rights reserved" data waiver (CC0 1.0 Public domain dedication).

Dataset 1: Sociodemographic characteristics, and results from the IHLQ and LSQ questionnaires, before, immediately after and 3 weeks after intervention for control and intervention groups. DOI, 10.5256/f1000research.13838.d195054 ³¹