Journal of Medical Internet Research - International Scientific Journal for Medical Research, Information and Communication on the Internet #Preprint #PeerReviewMe: Warning: This is a unreviewed preprint. Readers are warned that the document has not been peer-reviewed by expert/patient reviewers or an academic editor, may contain misleading claims, and is likely to undergo changes before final publication, if accepted, or may have been rejected/withdrawn. Readers with interest and expertise are encouraged to sign up as peer-reviewer, if the paper is within an open peer-review period. Please cite this preprint only for review purposes or for grant applications and CVs (if you are the author). Background: Regular physical activity (PA), adequate gestational weight gain (GWG) and healthy eating are important for the long-term health of both mother and baby. Hence, it is important that women receive current and updated advice on these topics, and are encouraged to adopt a healthy lifestyle during pregnancy. Objective: The aim of this study was to investigate the main information sources among pregnant women regarding PA, GWG and nutrition, as well as evaluate how these information sources may affect their health behaviours. Methods: A cross-sectional study design, comprising an electronic questionnaire, was distributed to two antenatal clinics, as well as pregnancy-related online chat forums and social media. Inclusion criteria were ≥ 18 years, ≥ 20 weeks gestation and able to read/write Norwegian. In total, 150 pregnant women answered the questionnaire, which was a mix of 11-point Likert scales, close-ended questions and semi close-ended questions with the option to elaborate. The relationship between information sources and selected variables, including health behaviours and descriptive variables, were assessed by logistic regression, linear regression or X2 as appropriate (p < 0.05). Results: Mean age (years), gestation week and pre-pregnancy BMI (kg/ m2) were 31.1 (± 4.3), 30.6 (± 5.9) and 24.2 (± 4.2), respectively. More than eight out of ten had received or retrieved information about nutrition (89%) and PA (80%), whereas 54% reported information on GWG. When combining all three lifestyle factors, 38.5% had retrieved information from blogs and Internet forums, and 26.6% from their midwife or family physician. Women reporting Internet and media as their primary source of information on weight gain had increased odds of gaining below the IOM guidelines (OR = 15.5, CI 1.4 – 167.4, P = 0.02). Stating Internet and media as main source on nutritional information was also associated with higher compliance with nutritional guidelines (P = 0.03). On the other side, receiving advice from family and friends on weight gain was significantly associated with gaining above the IOM guidelines (OR = 12.0, CI 1.3 – 111.7, P = 0.03). Otherwise, no other associations were found between information sources and health behaviours. Conclusions: The small number of health professionals giving information, and the extensive use of Internet and media based sources, emphasize the need to address the quality of Internet advice and guide women towards trustworthy sources of information during pregnancy. The association between information sources and PA, GWG and nutrition requires further research.

Regular exercise during pregnancy is beneficial, but athletes often exceed the recommended 150 min of moderate-intensity activity, incorporate high-intensity exercises. The upper limit for exercise intensity and duration on fetal and maternal safety remains uncertain. A concern is a maternal core body temperature of >39.0 °C, potentially increase the risk of heat-related fetal malformations and complications during pregnancy. Blood flow redirection for thermoregulation could compromise fetal cardiovascular function, increasing the risk of miscarriage and preterm labor. This study evaluated whether pregnant women (gestational weeks 25–35) were at risk of exceeding a core body temperature of 39.0 °C during high-intensity running. We also investigated effects on skin temperature, fluid loss, and thermal sensation, comparing pregnant athletes to non-pregnant controls. In this comparative cross-sectional study, 30 elite and recreational athletes (pregnant n = 15) completed up to five high-intensity treadmill-intervals. Core and skin temperature were continuously measured. Body weight was utilized to calculate the amount of fluid loss. Highest core body temperature were 38.76 °C and 39.56 °C in one pregnant and non-pregnant participant, respectively. Pregnant participants had lower core body temperatures (mean difference −0.47 °C, p ≤ 0.001) initially and a smaller increase (0.10 °C, p ≤ 0.003) during later intervals compared with the non-pregnant controls. Pregnant participants also showed a greater increase in skin temperature (4.08 ± 0.72 °C vs. 3.25 ± 0.86 °C, p = 0.008) and fluid loss (0.81 ± 0.19 L vs. 0.50 ± 0.12 L, p˂0.001). Physiological changes in pregnancy may enhance thermoregulation, indicating that high-intensity interval runs are unlikely to pose a risk of exceeding a core body temperature of 39 °C for pregnant athletes.

Objectives: To explore the acute effects of high-intensity interval training on fetal heart rate (FHR) and uteroplacental blood flow. Method: Elite (n=10) and recreational athletes (n=50) participated in an experimental laboratory study involving 5×5 min intervals of high-intensity exercise on both a treadmill and cycle ergometer, with a 4 min pause between intervals for measurement of FHR and uteroplacental blood flow. Target intensity was 17 on Borg’s rating of perceived exertion (RPE) scale and 90% of estimated maximal maternal heart rate (MHR_max). Results: Mean exercise intensity was 16.4 (SD 1.0) RPE and 89.4 (SD 3.8) % of MHR_max during running and 16.0 (SD 1.0) RPE and 84.6 (SD 5.0) % of MHR_max during cycling. Mean FHR was 140.9 (SD 27.4) beats per minute (bpm) during pauses between running bouts and 148.9 (SD 16.0) bpm during pauses between cycling bouts. Six cases of prolonged fetal bradycardia (3 min) occurred during running, leading to the termination of exercise. The mothers exercised at 17–18 on Borg’s RPE scale and 86.4%–92.6% of MHR_max in these cases. All cases were normalised within 8 min of ending the protocol. There were no cases of prolonged fetal bradycardia during cycling. Exercise was terminated for three women during running and two women during cycling due to fetal tachycardia (≥180 bpm for >4 min during rest). Conclusion: Despite cases of fetal bradycardia and tachycardia, our results indicate that highly active women can engage in multiple intervals of high-intensity interval training without apparent harm to fetal well-being.

Few studies have explored the associations between body satisfaction and physical activity and weight gain during pregnancy, and none have been conducted in Scandinavia. Hence, the aim of the present study was to evaluate changes in body satisfaction from pre-pregnancy to late pregnancy and investigate whether this differed according to parity. We also wanted to explore the association between body satisfaction and physical activity and weight gain among pregnant women in Norway. This cross-sectional survey used an electronic questionnaire to assess physical activity level, weight gain and women’s satisfaction with body weight and size. In total, 150 pregnant women answered the questionnaire. Related-samples Wilcoxon signed rank tests, Mann–Whitney U tests and chi-square tests were used to answer our research questions. The proportion of women who were dissatisfied with their body weight and shape increased from pre-pregnancy to late gestation (body weight p = 0.030 and body shape p = 0.040). Body dissatisfaction before and during pregnancy was linked to weight gain above recommendations. Characterising oneself as physically active prior to pregnancy was associated with satisfaction with body shape pre-pregnancy. Given that mothers strongly influence how a child will judge their body later in life, the results of this study underline the importance of addressing these issues during pregnancy.

Objectives: To explore the acute effects of a heavy-load resistance protocol and exercise in the supine position on fetal heart rate (FHR) and uteroplacental blood flow. Method: In this experimental laboratory study, 48 healthy pregnant athletes (elite: n=7; recreational: n=41) completed 3×8 repetitions with one repetition in reserve in sumo deadlift, bench press and incline bench press. FHR and umbilical and uterine artery pulsatility index (PI) were assessed before and after exercise. Symptoms of vena cava syndrome were recorded following the supine exercise. Results: Pre- and post-exercise FHR remained within the normal range (110–160 bpm), but there were statistically significant increases after sumo deadlifts (p=0.002) and incline bench press (p=0.008), with no significant change after bench press (p=0.122). Umbilical artery PI did not change, while uterine artery PI significantly decreased after the sumo deadlift (p=0.005), bench press (p<0.001) and incline bench press (p160 bpm) occurred in four cases after sumo deadlift, five after bench press and three after incline bench press, though none exceeded pathological levels (>180 bpm). One recreational athlete experienced symptoms of vena cava syndrome after the supine exercise, coinciding with a slight decrease in umbilical artery PI, but with stable FHR. Conclusion: The results indicate that highly active women, especially those with resistance training experience, can safely engage in a heavy-load resistance protocol, including supine exercise, without jeopardising fetal well-being.

Background: Exercise during pregnancy is associated with numerous health benefits. However, guidelines for elite and recreational athletes, who often exceed general recommendations regarding intensity, duration, and frequency are lacking, and potential risks remain unclear. The aim of the study was to describe exercise levels, pregnancy, and maternal and neonatal health outcomes in elite and recreational athletes. Method: This study was part of the Strong Mama research project, which was carried out in Oslo, Norway, between October 2022 and February 2024. Sixty athletes (10 elite and 50 recreational) participated in the study. They completed an online survey during late pregnancy and participated in a structured telephone interview six weeks postpartum. The survey and interview collected data on exercise habits, pregnancy experiences, and maternal and neonatal health outcomes. Results: The athletes maintained high exercise levels during pregnancy, with elite athletes exercising an average of 11.6 h per week (SD 3.2) and recreational athletes exercising 7.0 h per week (SD 2.4). Most athletes resumed exercising within six weeks postpartum. Almost all pregnancies were planned, including six which involved fertility treatment. Most women (76.7%) had spontaneous onset of labor and vaginal deliveries to term (between 36 and 42 weeks). The mean birthweight was 3487 (SD 519.4, range 2600–4775) grams. Two of the elite athletes were diagnosed with gestational diabetes mellitus and two with hypertension during pregnancy. None of the 50 recreational athletes reported any pregnancy complications. Conclusion: High levels of exercise during pregnancy did not seem to negatively impact maternal or neonatal health in this descriptive sample of Norwegian elite and recreational athletes. However, more research is needed to confirm these findings.