A healthy, balanced diet during pregnancy is essential to support optimal growth and development of the fetus and the physiological changes that occur in the mother. Fundamental aspects of healthy dietary behaviors during pregnancy include consuming foods that contain optimal amounts of energy as well as macro and micronutrients, achieving appropriate weight gain, adhering to general and pregnancy-specific food safety recommendations, and avoiding ingestion of harmful substances [1
]. Previous studies have shown that if such behaviors are not adopted, there is an increased risk of adverse pregnancy outcomes including low birth weight [3
], preeclampsia [4
], pre-term birth [5
], and neurodevelopmental problems such as fetal alcohol spectrum disorder [6
Health Canada and The Public Health Agency of Canada provide several dietary recommendations to help women meet their increased caloric and nutrient needs (Table 1
). Additional recommendations include increasing water intake and avoiding foods associated with food-borne illnesses such as undercooked fish and meat, raw eggs, unpasteurized products, and raw sprouts [2
]. Although these guidelines exist to help women select a healthy diet, the extent to which women change their diets to meet pregnancy-related guidelines is unknown.
During pregnancy, motivation for eating a healthy diet may change relative to the non-pregnant state as women prepare for motherhood and consider the impact of their dietary intake on the baby’s health [10
]. Personal values and beliefs about nutrition in pregnancy, advice from health professionals, and physical and physiological changes may interact with determinants of eating behaviors present in the non-pregnant state (e.g., personal preferences, time, money) to change diet-related behaviors [11
]. Although most women are aware that healthy eating is important during pregnancy, women may lack knowledge of specific dietary recommendations or may not have the skills required to improve their diet [14
]. Healthy eating may also be challenging during pregnancy as women face barriers such as food aversions, cravings, nausea, vomiting, tiredness, constipation, hemorrhoids, and heartburn [15
]. Women may receive and follow advice from a variety of sources, including health professionals, peers, and educational resources, which influences their choices during pregnancy [16
While several international studies have assessed diet before and during pregnancy [17
], these studies have not examined reasons why women may be motivated to make such changes. Understanding factors that motivate or deter pregnant women from making dietary changes is important for devising appropriate means to promote healthy eating behaviors in this population. Therefore, the objectives of this study were to: (1) describe the dietary changes women report making during pregnancy; (2) describe why women made these dietary changes; and (3) determine what changes women make that align with prenatal nutrition recommendations and what motivates them to make these changes.
2. Materials and Methods
The present study is a cross-sectional analysis of data collected from the first 400 participants in the Alberta Pregnancy Outcomes and Nutrition (APrON) Study; a prospective cohort study of over 2000 women in Alberta, Canada, with the main aim of examining the link between diet and the mental and physical health of pregnant women and their children [20
]. Participants included in this analysis were recruited from medical facilities, local maternity/baby-related businesses, via media campaigns, and the study website. Inclusion criteria were being pregnant at <28 weeks of gestation, over 16 years of age, fluent in English, and residing in the Calgary or Edmonton (Alberta, Canada) areas. Questionnaires used in this study were completed by participants at their first visit with the APrON team, at an average gestational age of 18 weeks gestation (range: 4–34 weeks).
Ethical approval was obtained from the Human Research Ethics Boards at the University of Alberta (project identification code: PRO00002954) and the University of Calgary (project identification code: REB14-1702_REN4). All participants provided written informed consent prior to data collection.
Maternal demographics information was collected by a questionnaire and included women’s current age, pre-pregnancy weight, self-reported gestational age, ethnicity, level of education, marital status, and household income. Height was measured using a digital stadiometer (Charder HM200P Portstad Portable Stadiometer, Charder, Taichung City, Taiwan) and was used with self-reported pre-pregnancy weight to calculate pre-pregnancy body mass index (BMI).
Dietary changes made were assessed using a Dietary Changes Questionnaire designed for the current study (see supplementary materials Table S1
for a copy of the questionnaire). The completed questionnaire was examined for face validity by four prenatal nutrition experts and two researchers with expertise in nutrition survey development. The Dietary Changes Questionnaire was an open-ended survey that asked participants to use their own words to describe the changes they made to their diet since becoming pregnant by listing all foods, beverages, and supplements that they had decreased, eliminated, increased, or added to their diets. For each of the items changed, participants were asked to include the frequency of consumption before and during pregnancy, the normal serving size, and the reason for the change. Sample answers were provided for each question as a guide. Because of the self-reported nature of this questionnaire, the information gathered reflects women’s perceptions of the changes they made and their beliefs about why changes were made.
Answers from completed questionnaires were entered into an Excel spreadsheet (Microsoft Excel, version 12.3.0, 2008, Microsoft, Redmond, WA, USA) and were analyzed using content analysis, a hybrid qualitative and quantitative approach involving examining text for themes or categories, and quantifying the appearance of those categories in the dataset [21
]. Individual foods that women reported changing were grouped into categories. Foods were grouped according to the four food groups in the Eating Well with Canada’s Food Guide (EWCFG) [9
]. Foods that fit into two or more EWCFG food groups were assigned to a “Mixed Dish” group (e.g., pizza, casseroles). Foods that did not fit with any of the EWCFG food groups were assigned to an “Other Foods” group, which consisted primarily of foods high in salt, sugar, and/or fat and low in nutrients. This Other Foods group was further subdivided into sweet (e.g., candy, chocolate), savory (e.g., pickles, potato chips), spicy (e.g., salsa, hot sauce), and miscellaneous (e.g., gum, mustard) foods. Beverages that were part of a food group according to EWCFG, such as 100% fruit juice and milk, were included in their respective groups. Those not considered part of EWCFG (e.g., water, coffee, tea, alcoholic beverages) were placed into a “Beverages” group.
When analyzing the reasons women gave for making dietary changes in the Dietary Changes Questionnaire, responses were coded into categories, and the number of women reporting responses in each category was counted. Categories and examples of women’s reported reasons included: baby’s health (better for baby, worried about effect on baby); concern (avoiding caffeine, safety risk); aversion (does not taste good, not appealing); nausea (makes me nauseous, nausea); craving (craving sweets, satisfies my craving); nutrient (upping calcium, for omega-3s); to be healthy (good for me, healthier snack); enjoyment (tastes good, enjoy the saltiness); decrease illness (calms my stomach, helps with nausea); other (easy to eat, just because). When more than one reason was listed for a food item, each reason was coded separately. The validity of the analysis was improved by having all responses coded by two of the researchers (J.E.G., L.E.F.) working independently; any disagreements in coding were resolved by consensus.
Maternal age, pre-pregnancy BMI, and weeks of gestation are presented as mean, standard deviation, and range; additional demographic information is presented as the proportion of women reporting a particular answer. Frequencies of food items decreased, eliminated, increased, or added to the diet and the reasons reported for making the change were calculated. Differences in the changes made between women with different demographic characteristics (first vs. second or third trimester, first vs. second+ pregnancy, normal weight vs. overweight or obese and low vs. high income) were examined using t-tests to examine differences in the total number of changes and chi-square tests to examine differences in the frequencies of making individual changes. Data analysis was performed using PASW 18.0 (SPSS Inc., 2009, Chicago, IL, USA).
All participants who had completed both the demographics and dietary changes questionnaire were included in this analysis (n
= 379). The mean age of participants was 31 years (Standard Deviation (SD): 4.1 years) and, on average, they had a healthy pre-pregnancy BMI (Table 2
). Most women were Caucasian, had achieved an education level above a high school diploma, and reported an annual household income of greater than CAD70,000.
3.2. Dietary Changes
Women reported making an average of six changes to their diets (median: 6, range: 1–19). Women reported increasing or adding foods in the Vegetables and Fruit, Grain Products, Milk and Alternatives, and Other Food groups more frequently than they reported decreasing or eliminating these foods (Table 3
). Within the Vegetable and Fruit group, the increase came primarily from increasing fruit intake; 25% reported increasing fruit consumption and only 1% reported decreasing fruit intake, whereas, for vegetables, 13% of women reported increasing consumption and 13% reported decreasing or eliminating a vegetable. Women reported decreasing or eliminating foods from the Meats and Alternatives group more frequently than they reported increasing foods from this group.
In the Other Foods category, participants reported increasing the consumption of sweet foods (16.3%) more frequently than savory (11.3%) or spicy (1.3%) foods. When sweet foods and sweet beverages were combined, 25.1% of participants increased or added sweet items to their diets. More than half of participants reported eliminating a food item classified in the “Miscellaneous” category; these items included chewing gum, artificial sweeteners, garlic, and salad dressing. Beverage intake changed substantially during pregnancy as alcoholic beverages, coffee, and tea were frequently decreased or eliminated from the diet.
Differences in changes made were compared relative to key characteristics of the participants. Women who completed the questionnaire during their first trimester were more likely to report increasing their intake of grain products (29%) compared to those in their second or third trimesters (20%) (p = 0.01). Women pregnant with their first child made more changes on average (mean: 6.4 for primiparous vs. 5.5 for multiparous women, p < 0.01) and were more likely to report increasing their intake of vegetables and fruit (p < 0.001) and decreasing their intake of sweets (p = 0.05) compared to women who had other children. Women in the normal pre-pregnancy BMI category were more likely to increase consumption of meats and alternatives compared to those in the overweight or obese category (p = 0.03). Women whose household income was less than CAD70,000 per year were more likely to decrease their intakes of grain products compared to women with an income over CAD70,000 (p < 0.01).
3.3. Reasons for Changing Dietary Intake during Pregnancy
The most common reasons cited for reducing or eliminating specific foods or groups of foods were health of the baby, concern, aversions, and nausea (Table 4
). Cravings, nutritional content, health, enjoyment, and to decrease illness were the most frequently reported reasons to increase or add new food items to the diet. Foods consumed for a specific nutrient included nuts and seeds for protein (10.3%), cereal for fiber (9.2%), and fish for omega 3 fatty acids (4.6%). Items such as starches (26.8%), sweet foods (19.6%), and soda (12.5%), were commonly increased or added to the diet to help decrease illnesses including constipation, upset stomach, and heartburn.
3.4. Making Changes Aligning with Prenatal Nutrition Recommendations
The most common changes women made that were aligned with dietary recommendations included decreasing caffeine intake (77%), eliminating alcohol intake (53%), following food safety recommendations (i.e., eliminating soft cheese, raw fish or sushi, undercooked meat, unpasteurized milk products, raw or undercooked eggs) (53%), increasing milk and alternative intake (49%), and increasing vegetables and fruit intake (40%). Relatively few women made changes that would bring them in closer alignment with the following recommendations: increasing cooked fish intake (4% increased and 15% decreased intake of cooked fish) and increasing meat and alternative intake (21% increased and 30% decreased intake of meats and alternatives that met food safety recommendations for pregnancy).
The most common reasons women reported for making changes to meet caffeine, alcohol, and food safety recommendations were the baby’s health and concern. The primary reason women increased their intake of milk and alternatives was for the nutrient content, followed by enjoyment and craving. Women’s primary reasons for increasing their vegetable and fruit intake were for cravings, enjoyment, and for a nutrient (most commonly fiber).
Women who increased their intake of meats and alternatives most commonly reported making this change to satisfy a craving or for a particular nutrient (most commonly protein-only three women mentioned iron). Those who decreased their intake of meats and alternatives most commonly reported that the change was due to aversions or nausea. The most common reason women increased their cooked fish intake was the omega-3 fatty acid content. The main reason women reported for decreasing or avoiding cooked fish was to avoid mercury contamination.
While many women increased intake of folate containing foods during pregnancy (i.e., fruit, grain products made with enriched flour), the most common reasons for increasing these foods were cravings, enjoyment and, for grain products, to decrease illness. No women indicated that they increased their intake of grains or vegetables and fruit in their diet to improve their intake of folate or folic acid.