Mediterranean Diet Adherence and Health-Related Quality of Life during Pregnancy: Is the Mediterranean Diet Beneficial in Non-Mediterranean Countries?

This study aimed to examine the association of Mediterranean diet (MD) adherence and MD components with health-related quality of life (HRQoL) in pregnant women from Spain and Sweden. A total of 138 pregnant women from Spain (age: 32.9 ± 4.6 years old) and 302 pregnant women from Sweden (age: 31.3 ± 4.1 years old) were included. MD adherence was assessed with the Mediterranean food pattern (i.e., a MD index) at the 14-16th gestational weeks. HRQoL was assessed with the Spanish and Swedish versions of the 36-item Short-Form Health Survey (SF-36 and RAND-36, respectively) at the 14-16th and 34-37th gestational weeks. A greater MD adherence was associated with better physical functioning, bodily pain, vitality, emotional role, and mental health in cross-sectional associations (2nd trimester) in the Spanish sample (all p < 0.05). Furthermore, a greater MD adherence was associated with lower bodily pain in both Spanish and Swedish samples (both p < 0.05) in the 3rd trimester. The associations of MD adherence with pain seem to be explained by a greater intake of fiber, fish, fruits, nuts, and legumes (all p < 0.05). A greater MD adherence, driven by a higher intake of fiber, fish, fruits, nuts, and legumes, was associated with lower pain throughout pregnancy in both Mediterranean and non-Mediterranean populations.

Physical Activity, Body Composition, and Cardiometabolic Health during Pregnancy: A Compositional Data Approach.

PURPOSE: The aim of this study was to examine the cross-sectional and longitudinal associations of 24-h movement behaviors (sleep, sedentary behavior (SB), light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA)) with body composition and cardiometabolic health in i) early and ii) late pregnancy (gestational weeks 14 and 37). METHODS: This observational study utilized cross-sectional ( n = 273) and longitudinal data ( n = 242) from the HealthyMoms trial. Time spent in movement behaviors over seven consecutive 24-h periods (ActiGraph wGT3x-BT accelerometer), body composition (Bod Pod), and cardiometabolic health indicators (glucose levels, homeostatic model for insulin resistance (HOMA-IR), systolic and diastolic blood pressure, metabolic syndrome (MetS) score) were measured in early and late pregnancy. RESULTS: In early pregnancy, reallocating time to MVPA from LPA, SB, and sleep was associated with lower MetS score (adjusted γ = -0.343, P = 0.002). Correspondingly, reallocating time to LPA from SB and sleep in early pregnancy was associated with lower body weight (adjusted γ = -5.959, P = 0.047) and HOMA-IR (adjusted γ = -0.557, P = 0.031) at the same time point. Furthermore, reallocating time to LPA from SB and sleep in early pregnancy was associated with lower fat mass index (adjusted γ = -0.668, P = 0.028), glucose levels (adjusted γ = -0.315, P = 0.006), HOMA-IR (adjusted γ = -0.779, P = 0.004), and MetS score (adjusted γ = -0.470, P = 0.027) in late pregnancy. The changes in behaviors throughout pregnancy were not associated with body weight, body composition, and MetS score in late pregnancy. CONCLUSIONS: Our results demonstrated that increasing LPA or MVPA while reducing SB and sleep was associated with lower weight and more favorable cardiometabolic health in early pregnancy. In contrast, LPA in early pregnancy seems to be a stimulus of enough intensity to improve body composition and cardiometabolic health indicators in late pregnancy.

User engagement in relation to effectiveness of a digital lifestyle intervention (the HealthyMoms app) in pregnancy.

Although user engagement is generally considered important for the effectiveness of digital behavior change interventions, there is a lack of such data in pregnancy. The aim of this study was therefore to examine the associations of user engagement with the HealthyMoms app with gestational weight gain, diet quality and physical activity in pregnancy. The study involved secondary analyses of participant data from the intervention group (n = 134) in a randomized controlled trial to determine the effectiveness of a 6-month mHealth intervention (the HealthyMoms app) on gestational weight gain, diet quality and physical activity. In adjusted regression models, the total number of registrations from three self-monitoring features (i.e., for weight-, diet- and physical activity) was associated with lower gestational weight gain (ß = - 0.18, P = 0.043) and improved diet quality (ß = 0.17, P = 0.019). These findings were mainly attributable to the associations of physical activity registrations with lower gestational weight gain (ß = - 0.20, P = 0.026) and improved diet quality (ß = 0.20, P = 0.006). However, the number of app sessions and page views were not associated with any of the outcomes. Our results may motivate efforts to increase user engagement in digital lifestyle interventions in pregnancy. However, additional studies are needed to further elucidate the influence of different types of user engagement in digital pregnancy interventions on their effectiveness.Trial registration: ClinicalTrials.gov (NCT03298555); https://clinicaltrials.gov/ct2/show/NCT03298555 (date of registration: October 2, 2017; date of first enrolled participant: October 24, 2017).

Body composition, physical fitness and cardiovascular risk factors in 9-year-old children.

The independent associations of body composition and physical fitness components with cardiovascular disease (CVD) risk factors in childhood are not fully understood. Thus, this cross-sectional study examined the independent associations of body composition and physical fitness with CVD risk factors in Swedish 9-year-old children (n = 411). Unadjusted linear regression analyses showed that body mass index (BMI), % fat mass and fat mass index were all positively associated with systolic and diastolic blood pressure, Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) and Metabolic Syndrome (MetS) score (all ß ≥ 0.229, P ≤ 0.001). These associations were virtually unaffected by adjustments for basic covariates (child's age and sex, maternal educational level and maternal BMI), fat-free mass and physical fitness. Fat-free mass index had generally weak associations with CVD risk factors and no associations were statistically significant after adjustments (all P > 0.27). Greater cardiorespiratory fitness and motor fitness were associated with lower HOMA-IR and MetS score in unadjusted models (all ß ≤ - 0.158, P ≤ 0.039) but not after adjustments for basic covariates and body composition. These findings indicate that cardiovascular health promotion in childhood may focus on the maintenance of a healthy fat mass.

The effects of a lifestyle intervention (the HealthyMoms app) during pregnancy on infant body composition: Secondary outcome analysis from a randomized controlled trial.

BACKGROUND: Pregnancy has been identified as a window for childhood obesity prevention. Although lifestyle interventions in pregnancy can prevent excessive gestational weight gain (GWG), little is known whether such interventions also affect infant growth and body composition. OBJECTIVES: To investigate (i) the effects of a 6-month lifestyle intervention (the HealthyMoms app) on infant body composition 1-2 weeks postpartum, and (ii) whether a potential intervention effect on infant body composition is mediated through maternal GWG. METHODS: This is a secondary outcome analysis of the HealthyMoms randomized controlled trial. Air-displacement plethysmography was used to measure body composition in 305 healthy full-term infants. RESULTS: We observed no statistically significant effect on infant weight (ß = -0.004, p = 0.94), length (ß = -0.19, p = 0.46), body fat percentage (ß = 0.17, p = 0.72), or any of the other body composition variables in the multiple regression models (all p ≥ 0.27). Moreover, we observed no mediation effect through GWG on infant body composition. CONCLUSIONS: Our findings support that HealthyMoms may be implemented in healthcare to promote a healthy lifestyle in pregnant women without compromising offspring growth. Further research is required to elucidate whether lifestyle interventions in pregnancy also may result in beneficial effects on infant body composition and impact future obesity risk.

Self-reported (IFIS) versus measured physical fitness, and their associations to cardiometabolic risk factors in early pregnancy.

Physical fitness is a strong marker of health, but objective fitness measurements are not always feasible. The International FItness Scale (IFIS) for self-reported fitness is a simple-to-use tool with demonstrated validity and reliability; however, validation in pregnancy needs to be confirmed. Also, its association with cardiometabolic health in pregnant women is unknown. Hence, we examined (1) the validity of the IFIS with objectively measured fitness, and (2) the associations of self-reported versus objectively measured cardiorespiratory fitness (CRF) and muscular strength with cardiometabolic risk factors in early pregnancy. Women (n = 303) from the HealthyMoms trial were measured at gestational week 14 for: CRF (6-min walk test); upper-body muscular strength (handgrip strength test); self-reported fitness (IFIS), body composition (air-displacement plethysmography); blood pressure and metabolic parameters (lipids, glucose, insulin). Higher self-reported fitness was associated with better measured fitness (ANOVA overall p < 0.01 for all fitness types), indicating the usefulness of the IFIS in pregnancy. Furthermore, higher self-reported overall fitness and CRF were associated with lower cardiometabolic risk scores (ANOVA p < 0.001), with similar results shown for measured CRF (ANOVA p < 0.001). The findings suggest that IFIS could be useful to stratify pregnant women in appropriate fitness levels on a population-based level where objective measurement is not possible.

Associations of body composition and physical fitness with gestational diabetes and cardiovascular health in pregnancy: Results from the HealthyMoms trial.

The aim of this study was to examine associations of body composition (fat mass index, % fat mass, fat-free mass index, body mass index) and physical fitness (cardiorespiratory fitness and handgrip strength) with gestational diabetes and cardiovascular health in early pregnancy. This cross-sectional study utilized baseline data (n = 303) collected in early pregnancy from the HealthyMoms trial. Body composition was measured using air-displacement plethysmography, cardiorespiratory fitness was assessed by means of the 6-min walk test and handgrip strength using a dynamometer. Logistic regression was used to estimate odds ratios (ORs) for gestational diabetes as well as high (defined as 1 SD above the mean) blood pressure, homeostatic model assessment for insulin resistance (HOMA-IR), and metabolic syndrome score (MetS score) per 1 SD increase in body composition and fitness variables. Fat mass index, % fat mass and body mass index were all strongly associated with gestational diabetes (ORs: 1.72-2.14, P ≤ 0.003), HOMA-IR (ORs: 3.01-3.80, P < 0.001), blood pressure (ORs: 1.81-2.05, P < 0.001) and MetS score (ORs: 3.29-3.71, P < 0.001). Associations with fat-free mass index were considerably weaker (ORs: 1.26-1.82, P = 0.001-0.15) and were strongly attenuated after adjustments for fat mass index (ORs: 0.88-1.54, P = 0.039-0.68). Finally, greater cardiorespiratory fitness was associated with lower risk of high HOMA-IR and MetS score (ORs: 0.57-0.63, P ≤ 0.004) although these associations were attenuated when accounting for fat mass index (ORs: 1.08-1.11, P ≥ 0.61). In conclusion, accurately measured fat mass index or % fat mass were strongly associated with gestational diabetes risk and markers of cardiovascular health although associations were not stronger than the corresponding ones for body mass index. Fat-free mass index had only weak associations with gestational diabetes and cardiovascular health which support that the focus during clinical care would be on excess fat mass and not fat-free mass.

Participants' Engagement and Satisfaction With a Smartphone App Intended to Support Healthy Weight Gain, Diet, and Physical Activity During Pregnancy: Qualitative Study Within the HealthyMoms Trial.

BACKGROUND: Excessive gestational weight gain (GWG) is common and associated with negative health outcomes for both mother and child. Mobile health-delivered lifestyle interventions offer the potential to mitigate excessive GWG. The effectiveness of a smartphone app (HealthyMoms) was recently evaluated in a randomized controlled trial. To explore the users' experiences of using the app, a qualitative study within the HealthyMoms trial was performed. OBJECTIVE: This qualitative study explored participants' engagement and satisfaction with the 6-month usage of the HealthyMoms app. METHODS: A total of 19 women (mean age: 31.7, SD 4.4 years; mean BMI: 24.6, SD 3.4 kg/m2; university degree attainment: 13/19, 68%; primiparous: 11/19, 58%) who received the HealthyMoms app in a randomized controlled trial completed semistructured exit interviews. The interviews were audiorecorded and fully transcribed, coded, and analyzed using thematic analysis with an inductive approach. RESULTS: Thematic analysis revealed a main theme and 2 subthemes. The main theme, "One could suit many: a multifunctional tool to strengthen women's health during pregnancy," and the 2 subthemes, "Factors within and beyond the app influence app engagement" and "Trust, knowledge, and awareness: aspects that can motivate healthy habits," illustrated that a trustworthy and appreciated health and pregnancy app that is easy to use can inspire a healthy lifestyle during pregnancy. The first subtheme discussed how factors within the app (eg, regular updates and feedback) were perceived to motivate both healthy habits and app engagement. Additionally, factors beyond the app were described to both motivate (eg, interest, motivation, and curiosity) and limit (eg, pregnancy-related complications, lack of time) app engagement. The second subtheme reflected important aspects, such as high trustworthiness of the app, increased knowledge, and awareness from using the app, which motivated participants to improve or maintain healthy habits during pregnancy. CONCLUSIONS: The HealthyMoms app was considered a valuable and trustworthy tool to mitigate excessive GWG, with useful features and relevant information to initiate and maintain healthy habits during pregnancy. TRIAL REGISTRATION: ClinicalTrials.gov NCT03298555; https://clinicaltrials.gov/ct2/show/NCT03298555. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR2-10.2196/13011.

Effectiveness of a Smartphone App to Promote Healthy Weight Gain, Diet, and Physical Activity During Pregnancy (HealthyMoms): Randomized Controlled Trial.

BACKGROUND: Excessive gestational weight gain (GWG) during pregnancy is a major public health concern associated with negative health outcomes for both mother and child. Scalable interventions are needed, and digital interventions have the potential to reach many women and promote healthy GWG. Most previous studies of digital interventions have been small pilot studies or have not included women from all BMI categories. We therefore examined the effectiveness of a smartphone app in a large sample (n=305) covering all BMI categories. OBJECTIVE: To investigate the effectiveness of a 6-month intervention (the HealthyMoms app) on GWG, body fatness, dietary habits, moderate-to-vigorous physical activity (MVPA), glycemia, and insulin resistance in comparison to standard maternity care. METHODS: A 2-arm parallel randomized controlled trial was conducted. Women in early pregnancy at maternity clinics in Östergötland, Sweden, were recruited. Eligible women who provided written informed consent completed baseline measures, before being randomized in a 1:1 ratio to either an intervention (n=152) or control group (n=153). The control group received standard maternity care while the intervention group received the HealthyMoms smartphone app for 6 months (which includes multiple features, eg, information; push notifications; self-monitoring; and feedback features for GWG, diet, and physical activity) in addition to standard care. Outcome measures were assessed at Linköping University Hospital at baseline (mean 13.9 [SD 0.7] gestational weeks) and follow-up (mean 36.4 [SD 0.4] gestational weeks). The primary outcome was GWG and secondary outcomes were body fatness (Bod Pod), dietary habits (Swedish Healthy Eating Index) using the web-based 3-day dietary record Riksmaten FLEX, MVPA using the ActiGraph wGT3x-BT accelerometer, glycemia, and insulin resistance. RESULTS: Overall, we found no statistically significant effect on GWG (P=.62); however, the data indicate that the effect of the intervention differed by pre-pregnancy BMI, as women with overweight and obesity before pregnancy gained less weight in the intervention group as compared with the control group in the imputed analyses (-1.33 kg; 95% CI -2.92 to 0.26; P=.10) and completers-only analyses (-1.67 kg; 95% CI -3.26 to -0.09; P=.031]). Bayesian analyses showed that there was a 99% probability of any intervention effect on GWG among women with overweight and obesity, and an 81% probability that this effect was over 1 kg. The intervention group had higher scores for the Swedish Healthy Eating Index at follow-up than the control group (0.27; 95% CI 0.05-0.50; P=.017). We observed no statistically significant differences in body fatness, MVPA, glycemia, and insulin resistance between the intervention and control group at follow up (P≥.21). CONCLUSIONS: Although we found no overall effect on GWG, our results demonstrate the potential of a smartphone app (HealthyMoms) to promote healthy dietary behaviors as well as to decrease weight gain during pregnancy in women with overweight and obesity. TRIAL REGISTRATION: ClinicalTrials.gov NCT03298555; https://clinicaltrials.gov/ct2/show/NCT03298555. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR2-10.2196/13011.

Body mass index and gestational weight gain in migrant women by birth regions compared with Swedish-born women: A registry linkage study of 0.5 million pregnancies.

INTRODUCTION: Women migrating to high-income countries may have increased risks of adverse pregnancy outcomes as compared with native-born women. However, little is known whether migrant women are more likely to have unhealthy body mass index (BMI) or gestational weight gain (GWG), which is of importance considering the well-established links between unhealthy BMI and GWG with adverse pregnancy outcomes. Hence, the aim of the study was to examine the prevalence and estimate odds ratios (ORs) of underweight and obesity in the first trimester as well as inadequate and excessive GWG across birth regions in migrant (first-generation) and Swedish-born women in a population-based sample of pregnant women in Sweden. METHODS: This population-based study included 535 609 pregnancies from the Swedish Pregnancy Register between the years 2010-2018. This register has a coverage of approximately 90% and includes data on body weight, height, birth country and educational attainment. BMI in the first trimester of pregnancy was classified as underweight, normal weight, overweight and obesity whereas GWG was classified as inadequate, adequate and excessive according to the recommendations from the National Academy of Medicine, USA. BMI and GWG were examined according to 7 birth regions and the 100 individual birth countries. Adjusted ORs of underweight, obesity as well as inadequate or excessive GWG by birth regions were estimated using multinomial logistic regression. RESULTS: There were large disparities in unhealthy BMI and GWG across birth regions. For instance, women born in North Africa and Middle East and Sub-Saharan Africa had 1.40 (95% CI 1.35-1.44) and 2.13 (95% CI 2.03-2.23) higher odds of obesity compared with women born in Sweden. However, women born in Sub-Saharan Africa had also considerably higher odds of underweight (OR, 2.93 [95% CI 2.70-3.18]) and inadequate GWG (OR, 1.97 [95% CI 1.87-2.07]). The limitations of the study include the lack of a validated measure of acculturation and that the study only had data on first-generation migration. CONCLUSIONS: The large differences across the 7 regions and 100 countries highlights the importance of considering birth region and country-specific risks of unhealthy BMI and GWG in first-generation migrant women. Furthermore, inadequate GWG was common among pregnant first-generation migrant women, especially in women born in Sub-Saharan Africa, which demonstrates the need to promote adequate GWG, not only the avoidance of excessive GWG. Thus, our findings also indicate that additional support and interventions may be needed for first-generation migrant women from certain birth regions and countries in order to tackle the observed disparities in unhealthy BMI and GWG. Although further studies are needed, our results are useful for identifying groups of women at increased risk of unhealthy BMI and weight gain during pregnancy.

Ultra-processed food advertisements dominate the food advertising landscape in two Stockholm areas with low vs high socioeconomic status. Is it time for regulatory action?

BACKGROUND: Ultra-processed food consumption is a risk factor for obesity and has a negative environmental impact. Food companies spend billions of dollars on advertisements each year to increase the consumption of ultra-processed food. In Australia, USA, and New Zealand, most food advertisements around schools and in train stations promote ultra-processed food, but no similar studies have been conducted in Sweden. The aim of this study was to explore the proportion of ultra-processed food advertisements in two districts of Stockholm, Sweden with low vs. high socioeconomic status (SES). METHODS: Two independent researchers (per area) mapped all advertisements, including storefronts, in two Stockholm districts. During consecutive days, all advertisements were photographed in Skärholmen (low SES district), and Östermalmstorg (high SES district), on the streets inside and outside the subway stations, as well as inside and outside of local shopping malls. Advertisements promoting food products were identified and a trained dietician categorized whether they promoted ultra-processed foods. Chi-Square test was conducted to test for differences in the proportion of ultra-processed food advertisements between the two study areas. RESULTS: In total, 4092 advertisements were photographed in Skärholmen (n = 1935) and Östermalm (n = 2157). 32.8% of all advertisements promoted food, while 65.4% of food advertisements promoted ultra-processed foods. A significantly higher proportion of ultra-processed food advertisements out of total food advertisements was identified in the low SES area, irrespective of the researcher taking the pictures (74.6% vs. 61.8%, p < 0.001 and 70.4% vs. 54.8%, p = 0.001). There was no significant difference in the proportion of food advertisements out of total advertisements between the two areas. CONCLUSIONS: This study provides initial evidence about the scale and the differences in exposure to food advertisements across areas in Stockholm. The observed high proportion of ultra-processed food advertisements is concerning and is in sharp contrast to the Swedish dietary guidelines that recommend reduced consumption of such foods. Based on our results, residents in low SES areas might be more exposed to ultra-processed food advertisements than those in high SES areas in Stockholm. If such findings are confirmed in additional areas, they should be considered during the deployment of food advertisement regulatory actions.

Human sperm displays rapid responses to diet.

The global rise in obesity and steady decline in sperm quality are two alarming trends that have emerged during recent decades. In parallel, evidence from model organisms shows that paternal diet can affect offspring metabolic health in a process involving sperm tRNA-derived small RNA (tsRNA). Here, we report that human sperm are acutely sensitive to nutrient flux, both in terms of sperm motility and changes in sperm tsRNA. Over the course of a 2-week diet intervention, in which we first introduced a healthy diet followed by a diet rich in sugar, sperm motility increased and stabilized at high levels. Small RNA-seq on repeatedly sampled sperm from the same individuals revealed that tsRNAs were up-regulated by eating a high-sugar diet for just 1 week. Unsupervised clustering identified two independent pathways for the biogenesis of these tsRNAs: one involving a novel class of fragments with specific cleavage in the T-loop of mature nuclear tRNAs and the other exclusively involving mitochondrial tsRNAs. Mitochondrial involvement was further supported by a similar up-regulation of mitochondrial rRNA-derived small RNA (rsRNA). Notably, the changes in sugar-sensitive tsRNA were positively associated with simultaneous changes in sperm motility and negatively associated with obesity in an independent clinical cohort. This rapid response to a dietary intervention on tsRNA in human sperm is attuned with the paternal intergenerational metabolic responses found in model organisms. More importantly, our findings suggest shared diet-sensitive mechanisms between sperm motility and the biogenesis of tsRNA, which provide novel insights about the interplay between nutrition and male reproductive health.

Physical Activity and Mobile Phone Apps in the Preschool Age: Perceptions of Teachers and Parents.

BACKGROUND: Physical activity (PA) is already beneficial at the preschool age. In many countries, young children spend most of their days in the preschool setting, making it a common arena for PA interventions. Mobile health tools are becoming increasingly popular to promote PA in different populations; however, little is known about the interest for and how the preschool setting could incorporate such a tool. OBJECTIVE: This study aimed to examine how teachers and parents perceive PA in preschool-aged children in general and their perceptions of how a mobile phone app could be used to promote PA in the preschool setting. METHODS: Semistructured interviews were conducted with 15 teachers (93%, [14/15] women, mean age 43.5 years, 47%, [7/15] with a university degree and 10 parents [91%, 9/10] women, mean age 38.9 years, all with a university degree) recruited from 2 urban preschools in central Sweden. The interviews were recorded, fully transcribed, coded, and analyzed using thematic analysis by means of an inductive approach. RESULTS: The analysis revealed 4 themes: (1) children are physically active by nature, (2) the environment as a facilitator or a barrier, (3) prerequisites of the adult world, and (4) an app in the preschool setting-challenges and possibilities. Parents and teachers perceived preschoolers as being spontaneously physically active; however, high-intensity PA was perceived as low. The PA was specifically performed during the day in the preschool. Identified facilitators of PA were access to safe and engaging outdoor environments such as forests, spacious indoor areas, and adult involvement. Adult involvement was considered especially important for children preferring sedentary activities. Identified barriers for PA were restricted indoor and outdoor space, rules for indoor activities, and lack of adult involvement because of time constraints. The teachers perceived that they had limited skills and experiences using apps in general, although they also acknowledged the increasing role of technological tools in the curriculum. Thus, the teachers expressed an interest for an app designed as a support tool for them, especially for situations when PA was limited because of perceived barriers. They suggested the app to include accessible information regarding the health benefits of PA in children linked to a library of activities for different settings and seasons. Parents suggested interactive app features including problem-solving tasks and music and dance, but not video clips as they made children passive. CONCLUSIONS: Vigorous PA was perceived as low in preschool-aged children. Future tailoring of interventions in the preschool setting should work around barriers and support facilitators to PA, especially PA of high intensity. In such work, an app could serve as a source of inspiration for PA in different ages, settings, and seasons and thus reduce environmental and structural inequalities in the preschool setting.

A Smartphone App to Promote Healthy Weight Gain, Diet, and Physical Activity During Pregnancy (HealthyMoms): Protocol for a Randomized Controlled Trial.

BACKGROUND: Excessive gestational weight gain is common and associated with adverse outcomes both in the short and long term. Although traditional lifestyle-based interventions have shown to mitigate excess gestational weight gain, little is known about whether mobile Health (mHealth) apps can promote healthy weight gain, diet, and physical activity during pregnancy. OBJECTIVE: The primary aim of the HealthyMoms trial is to determine the effectiveness of a smartphone app (HealthyMoms) for mitigating excess gestational weight gain during pregnancy. Secondary aims are to determine the effectiveness of the app on dietary habits, physical activity, body fatness, and glycemia during pregnancy. METHODS: HealthyMoms is a two-arm randomized controlled trial. Women are being recruited at routine visits at the maternity clinics in Linköping, Norrköping and Motala, Sweden. Women are randomized to the control or intervention group (n=150 per group). All women will receive standard care, and women in the intervention group will also receive the HealthyMoms smartphone app. RESULTS: Recruitment of participants to the trial was initiated in October 2017, and 190 women have so far completed the baseline measurement. The baseline measures are estimated to be finalized in December 2019, and the follow-up measures are estimated to be completed in June 2020. CONCLUSIONS: This project will evaluate a novel smartphone app intervention integrated with existing maternity health care. If successful, it has great potential to be implemented nationally in order to promote healthy weight gain and health behaviors during pregnancy. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/13011.