The present study aimed to determine the prevalence of food insecurity in pregnant women and its association with gestational weight gain, neonatal birth weight, and pregnancy complications in Hamadan County in 2018. According to the findings, 32.5% of pregnant women had food security, and 67.5% had different degrees of food insecurity varying from food insecurity without hunger to severe hunger. In a study performed by Kazemi et al. in Qazvin, approximately 44% of pregnant women had food insecurity according to the Household Food Insecurity Access Scale (HFIAS) [29]. According to the HFIAS scale, the rate of food insecurity was 36.6% in pregnant women in Nova Scotia province of Canada [30]. In Ogun State, Nigeria, the short form of the Food Security Survey (six items) showed that 46.4% of the pregnant women had food insecurity [31]. In a study conducted in North Carolina, food insecurity was only 8% in pregnant women. Similar to the present research, the foregoing study used an 18-item USDA questionnaire [10]. As shown by the above-mentioned studies, there exist significant differences in the prevalence of food insecurity among pregnant women around the world. Such differences might be attributed to the various scales used to assess the food security status, leading to disparate reports on the prevalence of food insecurity in pregnant women. Another reason is the impact of numerous factors on the food security status of the household. Household food security is affected by myriad demographic and contextual factors, including socioeconomic status, ethnicity, age, education, head of household, job loss, no fixed job, no savings, single-parent households, increased size of household, age composition of family members, children under 18 years of age in the family, monthly household income, residential home ownership status, chronic illness of family members, and smoking habit of a family member [9]. In general, it can be said that the elements of food security include availability, access, and utilization. The presence of each element is necessary, but not sufficient for food security. Availability is related to the production, import, distribution, and exchange of food in the community. Access is based on factors such as family income and purchasing power, and utilization is dependent on the adequacy and health of the food, preparation, processing, and cooking of food, the nutritional attitudes of family members about food selection, and personal health [32, 33]. Nevertheless, the most common indicators of food security pertain to food consumption, measuring only part of the physiological adequacy of food security [34]. Food security may not be accounted for in these factors, and many confounding variables may play a role in household food security; therefore, it is not possible to definitively determine the prevalence of food insecurity.
Another objective of the current study was to investigate the association between food insecurity in pregnant women and their gestational weight gain. Based on the results, the increase in the severity of food insecurity reduced the gestational weight gain; thus, food insecurity had a negative impact on mothers' gestational weight gain by controlling the possible confounding variables. Mothers with "food insecurity with severe hunger" had around 1.5 kg less gestational weight gain compared with the "food secure" group, which is in contrast to the results of Laraia et al. In their study, food insecurity was assessed using a USDA questionnaire, and after controlling the confounding variables, it was shown that pregnant women with food insecurity had 1.87 kg more weight gain in comparison with food-secure pregnant women [10]. Another study reported that the probability of obesity in food-insecure pregnant women was 1.9 times higher than those without food insecurity [35]. A number of mechanisms influence the association between gestational weight gain and food insecurity: (i) food-insecure women might be economically dependent on low-cost, processed, and high-calorie foods; (ii) consumption of low-calorie and processed foods can entail weight gain over time; (iii) stress from food insecurity can lead to opting for "comfortable" foods or fat-rich, high sugar, and sodium-rich foods; and (iv) eating high-fat foods under stressful conditions is associated with visceral fat accumulation and weight gain in animals as well as humans [36]. However, there is further evidence indicating that food insecurity lowers the diet quality among women of childbearing age, reducing micronutrients and their energy intake by 50% [37]; this possibly corroborates the results of the present study. In addition, the inconsistency between the results of these studies and the present research is probably ascribed to the cultural differences in terms of dealing with these conditions. Moreover, different studies consider different classifications of food security and make use of various types of tools to assess the food security status.
The present study aimed to examine the relationship between food insecurity in pregnant women and their neonatal birth weight. The results showed that compared to food-secure mothers, the infants of those with food insecurity were born with lower weights, and the reduction was even more intense among different degrees of food insecurity. The maternal weight gain during pregnancy was another factor affecting the neonatal birth weight. The results seemed to be reasonable given that maternal weight gain was reduced with the increase in the severity of food insecurity. There is compelling evidence that poor maternal nutrition during pregnancy results in intrauterine growth restriction and weight loss at birth [38,39,40,41,42]. There was a statistically significant relationship between low birth weight and food insecurity in a study by Borders et al. [16]. In another study, carried out by Chowdhury et al. in Bangladesh, mothers with food insecurity had 38% higher odds of delivering babies with low birth weights compared with food-secure mothers [43].
Investigating the relationship between food insecurity in pregnant women and pregnancy complications was another purpose of the present study. Hypertension/preeclampsia, gestational diabetes, and anemia were the complications of pregnancy considered in the current research. The studied correlation between food insecurity and hypertension/preeclampsia revealed that with the increase in the severity of food insecurity, the number of hypertensive/preeclampsia patients decreased, such that the highest percentage of patients belonged to the food security group. The study of ORs showed that the probability of hypertension/preeclampsia in the food-insecure group without hunger, the food-insecure group with moderate hunger and the food-insecure group with severe hunger was 14, 57, and 47% lower than the secure group, respectively, but the trend was not statistically significant. In a study performed on 860 postpartum women in Qazvin, the risk of pregnancy hypertension and preeclampsia in the food-insecure group was 24% and about 4 times higher than the food-secure group [44]. The reason for such inconsistency might be attributed to the differences in the scale used for measuring the food insecurity of pregnant women and the approach by which the variable was classified. In the study conducted in Qazvin, the HFIAS was employed to classify the participants into food-secure and food-insecure groups. Meanwhile, it was not possible to control the possible confounding variables using multivariate regression due to the small number of hypertensive/preeclampsia individuals. In a study by Laraia et al., the probability of hypertension in the food-insecure group was 23% higher than the food-secure group after controlling the confounding variables, but the increase was not significant. Despite the common belief that pregnancy-induced hypertension is caused by metabolic disorders and, possibly, pre-pregnancy obesity, this condition might be less affected by diet, the effect of excessive weight gain during pregnancy or other causes might be greater than dietary status [10]. Food insecurity had similar relationships with gestational diabetes and hypertension/preeclampsia. In the present study, approximately 50% of the participants with gestational diabetes mellitus were food secure; furthermore, their number decreased with the increase in the severity of food insecurity, and the differences were statistically significant. The ORs showed that the probability of gestational diabetes in the food-insecure group without hunger, the insecure group with moderate hunger, and the food-insecure group with severe hunger was 56, 61, and 1.5 times lower than the food-secure group, respectively, but the trend was not statistically significant. Laraia et al. reported inconsistent results with the present study. In their research, after controlling the confounding variables, the probability of gestational diabetes in women with food insecurity was 2.35 times higher than those with food security [10]. In the present study, it was impossible to control the possible confounding variables, possibly explaining the inconsistency existing between the foregoing study and the present one. However, Khosravi et al. observed no significant association between gestational diabetes and food insecurity [45]. The association between food insecurity and gestational diabetes might be negatively correlated with poor health behavior and an unhealthy diet involving high fat intake during pregnancy [46]. Therefore, eating culture in any society may be a determinant of the incidence of gestational diabetes.
Another objective of the present study was to examine the relationship between food insecurity during pregnancy and anemia. The ORs revealed that the probability of anemia in the food-insecure group without hunger and the insecure group with moderate hunger was around 2 times higher than the food-secure group; however, this probability was reduced by 6% in the food-insecure group with severe hunger in comparison to the food-secure group. This result is confirmed by a study on the association between the second-trimester anemia and food insecurity. Their results showed that women with moderately secure food status were 2 times more likely to develop anemia compared to those with food security; this probability was 24% higher in women with food insecurity in comparison to those with food security. After controlling the confounding factors, the rate was 75% higher in women with relatively secure food status than those with food insecurity; moreover, this rate was 6% lower in food-insecure women compared to those with food security [10] Anemia during pregnancy might be more affected by higher blood volume, pregnancy nausea and vomiting, and lack of iron supplementation rather than dietary status [25]. Therefore, in both studies, anemia did not increase in individuals with food insecurity compared to food secure.
With every 10–30 positive outcomes, it is necessary to include a variable in the model to perform the logistic regression; due to the limited number of people with hypertension/preeclampsia, gestational diabetes, and anemia, it was impossible to perform logistic regression and control the effects of possible confounding variables on the research outcomes, which was one of the limitations of the current study. Furthermore, despite the significant relationship between the variables and certain demographic and midwifery variables, it was not possible to perform the logistic regression and control the effects of probable confounding variables on the research result. To obtain better results, more studies with appropriate sample sizes should be conducted to investigate the relationship between these complications and food insecurity in pregnancy.