Background
Assessing the influence of lifestyle during pregnancy on maternal and foetal health is increasingly becoming a matter of interest [
1‐
3]. Among these behaviours, physical activity (PA) may play an important role [
4‐
8]. The sedentary lifestyle adopted by many pregnant women predisposes them to obesity, hypertension or gestational diabetes mellitus (GDM) [
5,
6,
8], and the physiological changes occurring during gestation magnify this risk [
9]. Importantly, overweight or obesity during pregnancy is associated with a significantly higher risk of pre-term delivery [
10], birth-asphyxia-related complications [
11], pre-eclampsia, GDM, prolonged labour, caesarean section, wound infection, postpartum haemorrhage, early neonatal death or neonatal intensive care admission [
12‐
15], and infant mortality [
16].
Maternal levels of PA may decline during pregnancy likely as a result of the physical changes of pregnancy and due to a combination of social and psychological factors, such as the thinking that resting during pregnancy is the safest behaviour [
17,
18]. However, increasing PA levels during pregnancy is effective in the prevention of GDM, hypertension, dysnea, excessive gestational weight gain, and high birth weight, among others [
5,
7,
8,
19,
20]. Emerging evidence suggest that exercise training during pregnancy (including moderate-to-high intensity exercise) might provide beneficial effects on both maternal and foetal health without side effects [
21,
22]. Indeed, it has been shown that exercise during gestation prevents diastasis recti abdominis [
23] and that higher levels of strength or aerobic training are positively associated with hospital stay length, incidence of cesareans and Apgar test [
24]. Further, strength training may reduce the need for insulin in overweight pregnant with GDM [
25]. Finally, aerobic and strength exercise improve physical fitness and result in additional benefits [
26,
27]. Moreover, during pregnancy, not only the DNA of a new life is created, also programmed through epigenetics. In this sense, maternal exercise may have benefits on the newborn, such as higher neurodevelopment [
28,
29], better heart functioning, improved heart rate variability [
30] and less body fat [
28]. However, it is unknown the extent to which supervised exercise programs might improve inflammatory markers, antioxidant activity or bone biomarkers. Moreover, most of exercise programs conducted in pregnant women are performed at light-to-moderate exercise intensity, or are based on solely aerobic or strength training.
An optimal mental health during pregnancy is also a major concern. High levels of depression or anxiety during gestation and post-partum affect maternal quality of life, and in turn, could have a negative influence on the foetal and child health [
31,
32]. Exercise may improve the pregnant quality of life and reduce stress [
33‐
36], which might protect the foetus [
31]. Also, adequate sleep during gestation improves quality of life [
37], prevents stress and depression [
38‐
40] and GDM [
41,
42], reduces inflammatory signal [
43] and the incidence of preeclampsia, premature birth or caesarea [
44‐
46]. Further, optimal sleep in pregnancy is essential for the foetal development [
47] and a better mother-child relationship [
40]. However, pregnancy frequently affects sleep quality [
48,
49] and it would of clinical relevance to better understand whether an exercise program positively influences the pregnant sleep quality.
Therefore, the main objective of the GESTAtion and FITness (GESTAFIT) project randomized controlled trial (RCT) is to assess the effects of a novel supervised exercise intervention developed in overweight and grade I obese pregnant on maternal and foetal health.
The present methodological article describes the study design, procedures and methods that will be conducted in the “GESTAFIT project”.
Recruitment process and measurements procedures
The evaluation protocol scheme is shown in Table
2. The measurements will be carried out in different days. The first assessment day will coincide with the 12th gestational week visit to the gynaecologist at “San Cecilio” University Hospital, Granada, and potential participants will be individually informed about the study objectives, evaluation protocol and procedures. If the woman agrees to participate in the present RCT, the researcher will provide detailed information about each of the phases of the study, and the participant will be asked to read and sign written informed consent. Subsequently (on the same day), weight and height will be assessed. On the second assessment day (16th gestational week) participants will attend the research centre and they will complete the following assessments: nutritional and clinical information, blood pressure, resting heart rate and physical fitness. The initial survey (anamnesis) will be conducted through face-to-face interviews by trained staff in order to gather data on sociodemographic characteristics, reproductive history, history of illness (hypertension, diabetes, obesity, etc.), and diet. Other health information will be collected using a self-administered questionnaire and it will include personal questions regarding smoking and alcohol habits and indicators of socio-demographic and socio-economic status (such as personal and household income, educational level or marital status). This survey will also include questions regarding the employment of nutritional supplements or special diets. Participant will then receive the accelerometer and questionnaires to be completed there or at home, and will be asked to return them eight days later. Additionally, the Hospital will make an appointment with the participants during that week for the biochemical and urine samples collection. The third day of evaluation will consist on accelerometry and sleep quality assessment on the 24th week of gestation. The fourth day of evaluation will take place on the 34th week of gestation. This evaluation will be exactly the same to that performed in the second day of evaluation before the exercise program started (i.e. 16th gestational week), including biochemical assessments.
Table 2
Evaluation protocol scheme
Informed consent | X | | | | | |
1st day evaluation |
Sociodemographic data | | X | | | | |
Clinical history | | X | | X | X | X |
Weight and height | X | X | | X | | X |
Body composition (dual-energy x-ray absorptiometry) | | | | | | X |
Accelerometry | | X | X | X | | |
Physical fitness | | X | | X | | |
Nutritional study | | X | | X | | X |
Questionnaires to be fill there or at home between the 1st and 2nd evaluation days |
Low back-pain | | X | | X | | X |
Quality of life | | X | | X | | X |
Sleep quality | | X | X | X | | X |
Physical activity | | X | X | X | | X |
Self-perceived physical fitness | | X | X | X | | X |
Sexual function | | X | | X | | X |
Restless legs syndrome | | X | | X | | X |
Mental and positive health | | X | | X | | X |
2nd day evaluation: Accelerometers collection and review of questionnaires | | X | | X | | |
Maternal biochemical analysis | | X | | X | X | |
Umbilical cord blood sampling | | | | | X | |
Maternal urine sampling | | X | | X | X | |
Blood samples (5 mL) of all pregnant participants will be extracted at week 16th and 34th of gestation, and at delivery. Samples of venous and arterial blood from the umbilical cord (5 + 5 mL) at the time of delivery will be taken. In addition, samples of urine at 16 and 34 weeks gestation and delivery will be collected. All samples will be immediately frozen and conserved at −80 °C to avoid breaking the cold chain before being sent to the laboratory.
Exercise intervention
Most of exercise programs developed for pregnant women until now [
20,
27,
52] have been designed in compliance with the recommendations of the American College of Obstetrics and Gynaecology (ACOG) in 2002 [
53], or the Canadian Society for Exercise Physiology, among others [
54]. However, in 2011, Zavorsky & Longo [
55] launched a more actual, specific, and evidence-based guideline for exercise programs during pregnancy. Consequently, the exercise program that will be conducted in the present project has been developed accordingly to this guideline [
55]. Nonetheless, we have also followed similar studies [
56,
57] where aerobic and resistance training, as well as strengthening of the pelvic floor muscles [
58], have been developed successfully and in line with these recommendations [
57].
The exercise intervention (
n = 30) will be performed in three groups of 10 participants and will meet the training standards of the American College of Sports Medicine [
59] for adults. The groups will train 3 days/week (55–60 minutes per session) from the 17th week of gestation until delivery. The exercise sessions will be designed, carefully supervised, guided and instructed by qualified exercise professionals with experience in working with pregnant women.
The exercise program planning is shown in Table
3. The exercise intervention group will have different phases: a)
Information phase: which will involve the understanding of the intervention plan for them, the goals we want to work with them, and how we will perform it (one training session); b)
Movement Learning phase: theoretical and practical sessions with the explanation of movements and explanation of basic movement patterns (two training sessions); and c)
Physical Fitness Training phase: with training sessions aimed at improving fitness and weight management (from the 18th until the 34th gestational week), and training sessions focused on a correct pelvic mobilization for the delivery (after the 34th gestational week until delivery) in order to try to reduce caesarean section rate, delivery time and number of pushes [
23,
60].
Table 3
Supervised exercise intervention program
WARM-UP 10 min | Joint mobility and different walk modalities |
CONDITIONING 40 min | Training week | 1 | 2–4 | 5–6 | 7–8 | 9–10 | 11–12 | 13–14 | 15–16 | 17–18 | >19 |
Gestational week | 17 | 18–20 | 21–22 | 23–24 | 25–26 | 27–28 | 29–30 | 31–32 | 33–34 | >34 |
Intensity (RPE) | | 12–13 | 12–13 | 13–14 | 13–14 | 14–15 | 14–15 | 15–16 | 15–16 | |
Monday CIRCUIT (muscular and cardiovascular blocks) | Familiarization and acquisition of the basic movement patterns | 5 RE × 3 | 5 RE × 3 | 5 RE × 3 | 5 RE × 3 | 5 RE × 3 | 5 RE × 3 | 5 RE × 3 | 5 RE × 3 | Pelvic movements + integration pattern. Real transfer to delivery moment |
1 min REST | 1 min REST | 1 min REST | 1 min REST | 1 min REST | 1 min REST | 1 min REST | 1 min REST |
1 AE 5′ | 1 AE 5′ | 1 AE 5′ | 1 AE 5′ | 1 AE 5′ | 1 AE 5′ | 1 AE 5′ | 1 AE 5′ |
1 min REST | 1 min REST | 1 min REST | 1 min REST | 1 min REST | 1 min REST | 1 min REST | 1 min REST |
5RE ×3 | 5RE ×3 | 5RE ×3 | 5RE ×3 | 5RE ×3 | 5RE ×3 | 5RE ×3 | 5RE ×3 |
1AE 5′ | 1AE 5′ | 1AE 5′ | 1AE 5′ | 1AE 5′ | 1AE 5′ | 1AE 5′ | 1AE 5′ |
1 min REST | 1 min REST | 1 min REST | 1 min REST | 1 min REST | 1 min REST | 1 min REST | 1 min REST |
Wednesday (cardiovascular block) | Familiarization and acquisition of the basic movement patterns | Choreographies and aerobic exercises | Pelvic movements + integration pattern. Real transfer to delivery moment |
Friday CIRCUIT (muscular and cardiovascular blocks) | Familiarization and acquisition of the basic movement patterns | 5 RE × 3 | 5 RE × 3 | 5 RE × 3 | 5 RE × 3 | 5 RE × 3 | 5 RE × 3 | 5 RE × 3 | 5 RE × 3 | Pelvic movements + integration pattern. Real transfer to delivery moment |
1 min REST | 1 min REST | 1 min REST | 1 min REST | 1 min REST | 1 min REST | 1 min REST | 1 min REST |
1 AE 5′ | 1 AE 5′ | 1 AE 5′ | 1 AE 5′ | 1 AE 5′ | 1 AE 5′ | 1 AE 5′ | 1 AE 5′ |
1 min REST | 1 min REST | 1 min REST | 1 min REST | 1 min REST | 1 min REST | 1 min REST | 1 min REST |
5RE ×3 | 5RE ×3 | 5RE ×3 | 5RE ×3 | 5RE ×3 | 5RE ×3 | 5RE ×3 | 5RE ×3 |
1AE 5′ | 1AE 5′ | 1AE 5′ | 1AE 5′ | 1AE 5′ | 1AE 5′ | 1AE 5′ | 1AE 5′ |
1 min REST | 1 min REST | 1 min REST | 1 min REST | 1 min REST | 1 min REST | 1 min REST | 1 min REST |
COOL-DOWN 10 min | Myofascial release, stretching and relaxation exercises |
The exercise intensity will be prescribed as percentages of heart rate reserve (% HRR) [
55] and the ratings of perceived exertion (RPE) using the Borg 6–20 RPE scale [
61]. We will also employ the Karvonen formula to estimate the training heart rate (e.g. 65 % HRR for a pregnant with 185 bpm maximum heart rate and 80 bpm basal heart rate would be calculated as: Training Heart Rate = 0.65 * (185–80) + 80). Heart rate will be measured with heart rate monitors (Polar Electro OY, Finland) to control the intensity of the sessions. One third of the participants in the intervention group will wear heart rate monitors in 1/3 of the sessions, both randomly selected. Intensity (expressed as RPE) will be expected to range from 12 to 16.
The intensity will be adapted during the exercise program based on the week of gestation and each woman’s heart rate. The
Physical Fitness Training phase sessions until the 34th gestational week will consist of mixed work, composed of circuits where both muscular and cardiovascular conditioning will be implemented. This type of exercise training has been already developed by White et al. [
57] who demonstrated better results for both the prevention of GDM, preeclampsia and preterm births, and for increased vaginal vs. caesarean deliveries.
Each training session will include 10 min warm-up with walks, mobility and activation exercises. The main part will consist of 40 min exercises organized in circuit. The circuit will alternate muscular and cardiovascular blocks of concurrent training. Each muscle circuit will consist of a hip dominant movement exercise (e.g. deadlift exercises, hinge hip, swing hip), a dominant knee (e.g. squats, lunges) 2 pull movements, 1 push movement (push-ups adapted) and 1 CORE muscles movement. Cardiovascular blocks will take approximately 3 min and will be composed of aerobic exercises as different variants of step-ups, small choreographies, front and side trips. Sessions will finish with a 10 min cool-down period of stretching, breathing, relaxation exercises and myofascial relief [
62]. None of the proposed exercises will include Valsalva manoeuvre, supine positions, or high impact exercises that could go in detriment of the successful activation of the lumbo-abdominal belt, promote a decrease in venous return or alterations in blood pressure, among others. The exercise program volume and intensity programmed is also shown in Table
3.
To maximize adherence, several strategies will be implemented including music in all sessions and telephone calls following missed sessions. The researchers will control and register the presence of adverse events during the class and between classes.
The participants randomly assigned to the control group (
n = 30) will receive general advices about the positive effects of PA during pregnancy for her and the foetus’s health status. The researchers will give three seminar explaining 1) the benefits of exercise for a better pregnancy, prevention and treatment of GDM and excessive weight gain; 2) ergonomic advises, exercises to perform at home (e.g. stretching, resistance training) and strategies to increase their daily PA levels; 3) the benefits of the Mediterranean Diet and nutritional education. Moreover, we will prepare brochures describing the overall benefits of PA on health, and we will dispense general guidelines to increase the level of daily PA and optimum nutrition during pregnancy [
63,
64].
Discussion
This paper describes the protocol performed by a multidisciplinary team of experts in PA and exercise, nutrition, gynaecology and physiology that aims to determine the effects of a supervised exercise intervention developed in overweight and grade I obese pregnant on the mother and newborn health, and the influence of lifestyle during pregnancy on relevant, but no explored yet, maternal and foetal outcomes.
The intrauterine environment seems to be involved in programming and foetal offspring exposed to maternal stress, inappropriate diet, physical inactivity, obesity or hyperglycaemia, among others, may be prone to future metabolic alterations and chronic diseases [
26,
89‐
91]. Among these modifiable behaviours, PA is especially relevant during gestation [
4‐
6]. Increasing PA levels or exercising during pregnancy is an efficient tool to tackle cardiometabolic diseases such as GDM, and excessive maternal and neonatal weight gains [
5,
19,
92]. However, modern society sometimes treats pregnancy as a disease. For example, it qualifies as vulnerable women and are excluded from most studies [
93]. Furthermore, is noticeably that most of the interventions focus on improving pregnant health involve mere advices or counselling given face to face, or by phone (or both). Just few trials have investigated well-controlled individually tailored exercise interventions. Consequently, further trials, with objective outcome measures, are needed. Moreover, the influence of physical fitness on important maternal health markers during gestation, such as quality of life, positive health, inflammatory profile, bone health, or oxidative stress is unknown.
Exercise during pregnancy is safe [
21,
22] and side-effects are minimal [
53,
54] if pregnant adequate the intensity of such exercise to warrant foetal wellbeing [
94]. However, the exercise intensity suggested by the ACOG in 2002 [
53] and by Davenport et al. [
95] will not be adopted in the present RCT. This is firstly, because the minimum work intensity is stated at 101 bpm for all women (which constitute a low heart rate), and secondly, because they make an absolute estimation (independently of the woman’s age, basal heart rate, or physical fitness status). Thereby, in agreement with Zavorsky & Longo [
55], we advocate for modulating the intensity based on the % HRR, and the RPE.
Not less important for an optimal pregnancy is a healthy psychological status [
31,
32,
96]. In that sense, exercise represent an excellent opportunity to improve quality of life [
33] and reduce cortisol levels, which may in turn have a positively influence on the foetus and child [
31,
32]. Besides, it is unknown whether exercise could positively influence the characteristic worse sleep quality during gestation [
48,
49], which can alter the pregnant metabolic status [
41‐
43] and gestational outcomes [
44‐
46] and negatively affect the pregnant quality of life [
37‐
40] and the foetal development [
47].
There is a clear and compelling rationale for increased pregnancy research in order to address the therapeutic needs of pregnant women [
93]. Additionally, there is accumulating evidence that pregnancy provides a unique window into understanding fundamental mechanisms underlying observed links between a pregnant woman’s health and her later health and the health of her children [
93]. The information obtained from this RCT will therefore be of clinical and public health interest and will suggest future research. Further, the exercise intervention designed is novel and non-expensive, and can be easily transferred to other similar contexts. Consequently, the findings of the GESTAFIT Project will help the Health Systems to identify strategies for primary prevention and health promotion among overweight and obese pregnant.