Efeito do Exercício na Gestação

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1 of 12Ruchat S-M, et al. Br J Sports Med 2018;52:1347–1356. doi:10.1136/bjsports-2018-099399
Effectiveness of exercise interventions in the 
prevention of excessive gestational weight gain and 
postpartum weight retention: a systematic review 
and meta-analysis
Stephanie-May Ruchat,1 Michelle F Mottola,2 Rachel J Skow,3 Taniya S Nagpal, 
Victoria L Meah,4 Marina James,3 Laurel Riske,3 Frances Sobierajski,3 
Amariah J Kathol,3 Andree-Anne Marchand,5 Megan Nuspl,6 Ashley Weeks,7 
Casey E Gray,8 Veronica J Poitras,9 Alejandra Jaramillo Garcia,9 Nick Barrowman,10 
Linda G Slater,11 Kristi B Adamo,12 Gregory A Davies,13 Ruben Barakat,14 
Margie H Davenport3 
Review
To cite: Ruchat S-M, 
Mottola MF, Skow RJ, 
et al. Br J Sports Med 
2018;52:1347–1356.
 ► Additional material is 
published online only. To view 
please visit the journal online 
(http:// dx. doi. org/ 10. 1136/ 
bjsports- 2018- 099399).
For numbered affiliations see 
end of article.
Correspondence to
Dr Margie H Davenport, 
Program for Pregnancy and 
Postpartum Health, Faculty 
of Kinesiology, Sport, and 
Recreation, Women and 
Children’s Health Research 
Institute, Alberta Diabetes 
Institute, University of Alberta, 
Edmonton, Alberta, Canada; 
 mdavenpo@ ualberta. ca
Received 31 March 2018
Revised 20 July 2018
Accepted 24 July 2018
© Author(s) (or their 
employer(s)) 2018. No 
commercial re-use. See rights 
and permissions. Published 
by BMJ.
AbsTRACT
Objective Gestational weight gain (GWG) has been 
identified as a critical modifier of maternal and fetal 
health. This systematic review and meta-analysis aimed 
to examine the relationship between prenatal exercise, 
GWG and postpartum weight retention (PPWR).
Design Systematic review with random effects meta-
analysis and meta-regression. Online databases were 
searched up to 6 January 2017.
study eligibility criteria Studies of all designs in 
English, Spanish or French were eligible (except case 
studies and reviews) if they contained information on the 
population (pregnant women without contraindication 
to exercise), intervention (frequency, intensity, duration, 
volume or type of exercise, alone [“exercise-only”] or 
in combination with other intervention components 
[eg, dietary; “exercise + co-intervention”]), comparator 
(no exercise or different frequency, intensity, duration, 
volume or type of exercise) and outcomes (GWG, 
excessive GWG (EGWG), inadequate GWG (IGWG) or 
PPWR).
Results Eighty-four unique studies (n=21 530) were 
included. ’Low’ to ’moderate’ quality evidence from 
randomised controlled trials (RCTs) showed that exercise-
only interventions decreased total GWG (n=5819; 
−0.9 kg, 95% CI −1.23 to –0.57 kg, I2=52%) and PPWR 
(n=420; −0.92 kg, 95% CI −1.84 to 0.00 kg, I2=0%) and 
reduced the odds of EGWG (n=3519; OR 0.68, 95% CI 
0.57 to 0.80, I2=12%) compared with no exercise. ’High’ 
quality evidence indicated higher odds of IGWG with 
prenatal exercise-only (n=1628; OR 1.32, 95% CI 1.04 
to 1.67, I2=0%) compared with no exercise.
Conclusions Prenatal exercise reduced the odds 
of EGWG and PPWR but increased the risk of IGWG. 
However, the latter result should be interpreted with 
caution because it was based on a limited number of 
studies (five RCTs).
InTRODuCTIOn
Over the past three decades, gestational weight 
gain (GWG) has emerged as a critical modifier of 
maternal and fetal health during pregnancy that 
persists for years after delivery.1 Compared with 
adequate GWG (AGWG), excessive GWG (EGWG) 
and inadequate GWG (IGWG) have been associated 
with higher adverse maternal and infant outcomes. 
EGWG was associated with higher odds of large 
for gestational age (LGA) babies, macrosomia and 
caesarean delivery.2 IGWG was associated with 
increased odds of small for gestational age (SGA) 
babies and preterm birth; these associations were 
greatest with lower pre-pregnancy body mass index 
(BMI).2 Several studies have also highlighted that 
EGWG may contribute exponentially to the obesity 
epidemic in women.3 4 Taken together, these find-
ings highlight the importance of identifying and 
implementing prenatal strategies that promote 
AGWG. In fact, one of the initiatives for ‘'Healthy 
People 2020’' is to increase the proportion of preg-
nant women who achieve AGWG.5
A recent meta-analysis of 33 randomised 
controlled trials (RCTs; n=9320 women) conducted 
by the International Weight Management in Preg-
nancy Collaborative Network showed that diet- 
and physical activity-based interventions reduced 
GWG by an average of 0.70 kg (95% CI 0.92 to 
0.48) compared with the control group.6 Likewise, 
the most recent Cochrane review reported a risk 
reduction of EGWG with diet or exercise, or both 
interventions (overall result: 24 RCTs, n=7096; 
average RR 0.80, 95% CI 0.73 to 0.87).7 However, 
none of these meta-analyses examined whether a 
dose–response relationship existed between phys-
ical activity and GWG or whether prenatal phys-
ical activity impacted postpartum weight retention 
(PPWR).
International and national guidelines for exercise 
during pregnancy recommend that women without 
contraindications should be physically active 
throughout pregnancy.8 9 The present systematic 
review and meta-analysis was conducted as part of 
a series of reviews which form the evidence base for 
the development of the 2019 Canadian Guideline 
for Physical Activity throughout Pregnancy (herein 
referred to as the Guideline).10 The purpose of this 
review was to evaluate the effect of prenatal exer-
cise on GWG and PPWR.
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Table 1 Institute of Medicine (IOM) gestational weight gain recommendations15 16
IOM 199015 IOM 200916
Pre-pregnancy bMI category
Recommended range of total 
weight gain* Pre-pregnancy bMI category
Mean rate of weight gain in the 
second and third trimester†
Recommended range of total 
weight gain*
29.0 kg/m2  (obese) at least 6.0 kg ≥30‡ kg/m2
Obese
0.2 kg/week 5.0–9.0 kg
*Calculations assume a total of 0.5–2.0 kg weight gain in the first trimester.
†Rounded values.
‡A narrower range of weight gain may be advised for women with a pre-pregnancy BMI of 35.0 kg/m2 or greater. Individualised advice is recommended for these women.
MeThODs
In October 2015 the Guidelines Consensus Panel assembled to 
identify the priority outcomes for the Guideline update. The 
Panel included researchers, methodological experts, a fitness 
professional and representatives from the Canadian Society for 
Exercise Physiology (CSEP), the Society of Obstetricians and 
Gynaecologists of Canada (SOGC), the College of Family Physi-
cians of Canada, the Canadian Association of Midwives, the 
Canadian Academy of Sport and Exercise Medicine, Exercise is 
Medicine Canada and a representative health unit (the Middle-
sex-London Health Unit). Twenty ‘critical’ and 17 ‘important’ 
outcomes related to prenatal exercise and maternal or fetal 
health were selected by the Panel. Two of the ‘critical’ outcomes 
(ie, EGWG and PPWR) and two of the ‘important’ outcomes (ie, 
GWG and IGWG) are examined in this review. The Preferred 
Reporting Items for Systematic Reviews and Meta-Analyses 
(PRISMA) statement and checklist were used to guide this 
systematic review and meta-analysis.11
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	Effectiveness of exercise interventions in the prevention of excessive gestational weight gain and postpartum weight retention: a systematic review and meta-analysis
	Abstract
	Introduction
	Methods
	Protocol and registration
	Eligibility criteria
	Population
	Intervention (exposure)
	Comparison
	Outcomes
	Study design
	Information sources
	Study selection and data extraction
	Quality of evidence assessment
	Statistical analysis
	Results
	Study selection
	Study characteristics
	Quality of evidence
	Synthesis of data
	Excessive gestational weight gain
	Sensitivity analysis
	Subgroup analysis
	Inadequate gestational weight gain
	Sensitivity analysis
	Subgroup analysis
	Postpartum weight retention
	Sensitivity analysis
	Subgroup analysis
	Discussion
	Conclusion
	Referencesexamine the impact 
of prenatal exercise on fetal and maternal health outcomes, 
respectively, and records identified through both processes 
were considered for inclusion in the current review. Each 
review was registered a priori with the International Prospec-
tive Register of Systematic Reviews (PROSPERO; fetal health: 
CRD42016029869; maternal health: CRD42016032376). 
Since the relationships between prenatal exercise and maternal/
fetal health outcomes were examined in studies related to both 
maternal and fetal health, records retrieved from both of these 
searches were evaluated for inclusion in the current review.
eligibility criteria
This study was guided by the participants, interventions, compar-
isons, outcomes and study design (PICOS) framework.12
Population
The population of interest was pregnant women without 
contraindication to exercise (according to the CSEP and 
American College of Obstetricians and Gynaecologists guide-
lines).8 13 Absolute contraindications to exercise were defined 
as: ruptured membranes, premature labour, persistent second or 
third trimester bleeding, placenta previa, pre-eclampsia, gesta-
tional hypertension, incompetent cervix, intrauterine growth 
restriction, high order pregnancy, uncontrolled type 1 diabetes, 
hypertension or thyroid disease or other serious cardiovascular, 
respiratory or systemic disorders. Relative contraindications to 
exercise were defined as: a history of spontaneous abortion, 
premature labour, mild/moderate cardiovascular or respira-
tory disease, anaemia or iron deficiency, malnutrition or eating 
disorder, twin pregnancy after 28 weeks or other significant 
medical conditions.8 13
Intervention (exposure)
The intervention/exposure of interest was objectively or subjec-
tively measured prenatal exercise of any frequency, intensity, 
duration, volume or type (studies on exercise during labour 
were not eligible for inclusion). Although exercise is a subtype 
of physical activity, the terms are used interchangeably in this 
review. Exercise was defined as any bodily movement generated 
by skeletal muscles that resulted in energy expenditure above 
resting levels.14 Interventions that consisted of exercise alone 
(termed ‘exercise-only’ interventions) or exercise combined with 
other interventions (eg, diet; termed ‘exercise + co-interven-
tions’) were considered. Prenatal exercise could be acute (ie, a 
single exercise session) or habitual (ie, usual activity).
Comparison
Eligible comparators were: no exercise; different frequency, 
intensity, duration, volume or type of exercise; different inter-
vention duration; or exercise in a different trimester.
Outcomes
Relevant outcomes were total GWG, GWG and weekly GWG 
during the intervention time frame, EGWG, AGWG, IGWG 
and PPWR. Weekly GWG during the intervention was defined 
as the amount of weight the women gained during the inter-
vention time frame divided by the duration of the intervention 
(in weeks); EGWG, AGWG and IGWG were defined according 
to pre-pregnancy BMI of the women using either the 1990 or 
2009 Institute of Medicine (IOM) GWG recommendations (see 
table 1 for more details about the recommendations)15 16; and 
PPWR was defined as postpartum body weight minus pre-preg-
nancy body weight.
study design
Primary studies of any design were eligible, with the exception of 
case studies (n=1), narrative syntheses and systematic reviews.
Information sources
A comprehensive search was created and run by a research 
librarian (LGS) in the following databases: MEDLINE, EMBASE, 
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PsycINFO, Cochrane Database of Systematic Reviews, Cochrane 
Central Register of Controlled Trials, Scopus and Web of Science 
Core Collection, CINAHL Plus with Full-text, Child Develop-
ment & Adolescent Studies, ERIC, Sport Discus, ClinicalTrials. 
gov and the Trip Database up to 6 January 2017 (see online 
supplement for complete search strategies).
study selection and data extraction
Two independent reviewers screened the titles and abstracts of 
all articles identified in the search against the inclusion criteria. 
Abstracts that were selected as eligible at level 1 by at least one 
reviewer were retrieved for level 2 screening as a full-text article. 
Two independent reviewers screened full-text articles against the 
study inclusion criteria. When a study was recommended by one 
or more reviewers for exclusion, further review was conducted 
by MHD and/or SMR for a final decision. If a decision could not 
be made, the study characteristics were presented to the Guide-
lines Steering Committee who oversaw the systematic reviews 
(MHD, MFM, SMR, CG, VP, AJG and NB) and a final decision 
regarding inclusion/exclusion was made by consensus. Studies 
identified by the maternal and fetal search strategies were 
imported into DistillerSR for de-duplication and data extraction, 
and were subsequently considered as one review.
Following consultation with methodological experts and the 
Guidelines Steering Committee, data extraction was completed 
in DistillerSR and data extraction tables were created. Data 
from records that met the inclusion criteria were extracted 
by one person and independently verified by a content expert 
(MHD, MFM or SMR). For studies where multiple publications 
existed, the most recent or complete publication was selected 
as the ‘parent’ paper; however, relevant data from all publi-
cations were extracted. Extracted data included study charac-
teristics (ie, year, study design, country), characteristics of the 
population (eg, number of participants, age, pre-pregnancy BMI, 
parity and pregnancy complications including pre-eclampsia, 
gestational hypertension and gestational diabetes), intervention/
exposure (prescribed and/or measured exercise frequency, inten-
sity, duration, type and volume, intervention duration, measure-
ment tool), and outcomes (GWG, EGWG, AGWG, IGWG and 
PPWR). If data were unavailable for extraction, authors were 
contacted to request additional information. See online supple-
mentary table 1 for included study characteristics.
Quality of evidence assessment
The Grading of Recommendations Assessment, Development 
and Evaluation (GRADE) framework was used to assess the 
quality of evidence across studies for each study design and 
health outcome.17
Accordingly, evidence from RCTs was considered ‘high’ quality 
and was graded down if there was a concern with risk of bias,18 
indirectness,19 inconsistency,20 imprecision21 or risk of publica-
tion bias22 because these factors reduce the level of confidence 
in the observed effects. Evidence from all non-randomised inter-
ventions and observational studies began with a ‘low’ quality 
rating and, if there was no cause to downgrade, was upgraded 
if applicable according to the GRADE criteria (eg, large magni-
tude of effect, evidence of dose-response).23 Specifically, the risk 
of bias in RCTs and intervention studies was assessed following 
the Cochrane Handbook24 and the risk of bias in observational 
studies was assessed using the characteristics recommended by 
Guyatt et al,18 consistent with systematic reviews conducted to 
support previous health behaviour guidelines.25 26 All studies 
(RCTs, non-randomised intervention studies and observational 
studies) were assessed for potential sources of bias including 
selection bias (RCT/intervention: inadequate randomisation 
procedure; observational: inappropriate sampling), reporting 
bias (selective/incomplete outcome reporting), performance bias 
(RCT/intervention: compliance with the intervention; observa-
tional: flawed measurement of exposure), detection bias (flawed 
measurement of outcome), attrition bias (incompletefollow-up, 
high loss to follow-up) and ‘other’ sources of bias. Risk of bias 
across studies was considered 'serious’ when studies with the 
greatest influence on the pooled result (assessed using weight 
(%) given in forest plots or sample size in studies that were 
narratively synthesised) presented ‘high’ risk of bias. The greatest 
influence on the pooled result was determined as follows: the 
studies that had the greatest individual percent contribution in 
the meta-analyses, when taken together, contribute to >50% 
of the weight of the pooled estimate. Additionally, studies were 
considered to reflect a serious risk of bias when the sample 
size of narratively synthesised studies was similar to the total 
sample size of studies contributing to >50% of the weight of 
the pooled estimate in the meta-analyses. Given the nature of 
exercise interventions, it is not possible to blind participants to 
group allocation, and selection risk of bias was rated as ‘low’ 
if this was the only source of bias identified. Performance bias 
was rated as ‘high’ when 10% of data were missing at the end of the study and 
intention-to-treat analysis was not used.
Inconsistency across studies was considered serious when 
heterogeneity was high (I2 ≥50%) or when only one study was 
assessed (I2 unavailable). Indirectness was considered serious 
when interventions included both exercise and additional 
components (ie, exercise + co-interventions, or exercise-only 
and exercise + co-interventions combined in analyses). Impre-
cision was considered serious when the 95% CI crossed the line 
of no effect and was wide, such that interpretation of the data 
would be different if the true effect was at one end of the CI 
or the other. When only one study was assessed, imprecision 
was not considered serious because inconsistency was already 
considered serious for this reason. Finally, when possible (ie, at 
least 10 studies were included in the forest plot), publication bias 
was assessed via funnel plots (see online supplement). If there 
were fewer than 10 studies, publication bias was deemed non-es-
timable and not rated down. Original plans for two people to 
independently assess the quality of the evidence across each 
health outcome were amended for feasibility reasons. As such, 
one reviewer evaluated the quality of the evidence and a second 
person checked the GRADE tables as a quality control measure. 
GRADE tables are presented in online supplementary tables 2–8.
statistical analysis
Statistical analyses were conducted using Review Manager v5.3. 
(Cochrane Collaboration, Copenhagen, Denmark). Odds ratios 
were calculated for all dichotomous outcomes. Inverse-variance 
weighting was applied to obtain OR using a random effects model. 
For continuous outcomes, mean differences (MD) between 
exercise and control groups were calculated. When applicable, 
change scores were calculated using the generic inverse variance 
method (Cochrane Collaboration, Copenhagen).27 Significance 
was set at P25.0 kg/m2) compared with women who were of various 
BMI (mean BMI 25.0 kg/m2; named ‘general population’); (3) 
women >35 years of age compared with womenspecified, studies were not included in meta-analyses if data 
were reported incompletely (eg, SD, SE or number of cases/
controls not provided), if data were adjusted for confounding 
factors, or if the study did not include a non-exercise control 
group. In studies where data were included in the meta-anal-
ysis but additional information was available that could not be 
meta-analysed, the studies were included in both the meta-anal-
ysis and narrative synthesis.
ResulTs
study selection
Althought the initial search was not limited by language, the 
Guidelines Steering Committee decided to exclude studies 
published in languages other than English, Spanish or French 
for feasibility reasons. A PRISMA diagram of the search results, 
including reasons for exclusion, is shown in figure 1. A compre-
hensive list of excluded studies is presented in the online 
supplement.
study characteristics
Overall, 84 unique studies (n=21 530) from 26 countries were 
included. There were 79 RCTs (46 exercise-only interventions 
and 33 exercise + co-interventions), four non-randomised inter-
ventions and one cohort study. The co-interventions included 
diet and behavioural interventions to improve eating and phys-
ical activity habit and/or limit GWG. Among the exercise-only 
interventions, the frequency of the prescribed exercise ranged 
from 1 to 7 times per week. The majority of the studies targeted 
moderate-intensity exercise (Borg scale 12–14/20). The duration 
of each exercise session ranged from 10 to 90 min. The types 
of exercise were walking, swimming, stationary cycling, water 
gymnastics, resistance training, stretching, yoga or pelvic floor 
muscle training. The majority of the interventions started before 
20 weeks of gestation with most of the studies ending in the 
mid-to-late third trimester. Additional details about the studies 
can be found in the online supplement.
Quality of evidence
Overall, the quality of evidence ranged from ‘very low’ to 
‘high’ (see online supplementary tables 2-8). The most common 
reasons for downgrading the quality of evidence were (1) serious 
risk of bias; (2) inconsistency; and (3) indirectness of the inter-
ventions being assessed. Common sources of bias included poor 
or unreported compliance with the intervention and inappro-
priate treatment of missing data when the attrition rate was high. 
No evidence of publication bias was observed.
synthesis of data
Excessive gestational weight gain
There was ‘low’ quality evidence from 33 RCTs (n=9138) 
regarding the association between prenatal exercise and 
EGWG.35–67 The quality of evidence was downgraded from 
‘high’ to ‘low’ because of serious risk of bias and serious indi-
rectness of the interventions. The pooled estimate based on 
32 RCTs (n=8817) indicated 32% lower odds of EGWG with 
exercise compared with no exercise (OR 0.68, 95% CI 0.59 to 
0.78, I2=46%; figure 2).35–66 One exercise + co-intervention 
could not be included in the meta-analysis and showed that the 
proportion of women gaining above GWG recommendations 
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Figure 1 Flow diagram of studies selected for the present study. Among the 84 studies included, 74 were included in quantitative synthesis, but 
three were from the same study and counted as one unique study; 19 studies were included in qualitative synthesis, but six were from the same study 
and counted as one unique study; 16 studies were included in both the qualitative and quantitative synthesis.
did not differ between the groups (co-intervention group, 
n=158; control group, n=163) (RR 1.06, 95% CI 0.83 to 1.36; 
see online supplementary table 1).67
The results of the meta-regression analysis are presented in 
online supplementary figures 31–34). To achieve at least a 25% 
reduction in the odds of EGWG, pregnant women needed to 
exercise at least two times per week, 35 min/session or accu-
mulate at least 456 MET-min/week of moderate intensity exer-
cise (eg, 105 min of brisk walking, water aerobics, stationary 
cycling or resistance training per week).
Five RCTs included in the pooled results reported addi-
tional data that could not be included in the meta-analysis 
(see online supplementary table 1).41 47 60 62 68 Barakat et 
al47 and Ruiz et al41 reported 37–47% lower odds of EGWG 
with exercise-only interventions (after adjustment for several 
potential confounding factors) whereas Renault et al68 found 
no effect of an exercise-only intervention (OR 0.86, 95% CI 
0.68 to 1.08) compared with no exercise. In contrast, they 
found that an exercise + diet intervention reduced the odds of 
EGWG (OR 0.73, 95% CI 0.57 to 0.94).68 Phelan et al62 also 
reported lower odds of EGWG with an exercise + diet inter-
vention but only in women of normal pre-pregnancy weight 
(OR 0.38, 95% CI 0.20 to 0.87; women with overweight/
obesity: OR 1.4, 95% CI 0.70 to 2.7). Finally, Kinnunen et al60 
reported no effect of an exercise + diet intervention on the 
odds of EGWG (OR 0.82, 95% CI 0.53 to 1.26) after adjust-
ment for several potential confounding factors.
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Figure 2 Effects of prenatal exercise-only or exercise plus co-interventions (RCTs) compared with control on odds of excessive gestational weight 
gain. Analyses conducted with a random effects model. CI, confidence interval; df, df; M-H, Mantel–Haenszel method. NW: subgroup of women 
with normal weight; OW/OB: subgroup of women with overweight/obesity; OB: subgroup of women with obesity; Exercise: exercise arm of the 
intervention; Diet + exercise: diet + exercise arm of the intervention.
Sensitivity analysis
The pooled estimate for the exercise-only interventions was 
not significantly different from the pooled estimate for the 
exercise + co-interventions (P=0.89). Both exercise-only inter-
ventions and exercise + co-interventions reduced the odds of 
EGWG (figure 2). Specifically, there was ‘moderate’ quality 
evidence (downgraded due to serious risk of bias) indicating a 
32% reduction in the odds of EGWG with exercise-only inter-
ventions (15 RCTs, n=3519; OR 0.68, 95% CI 0.57 to 0.80, 
I2=12%).35–49
Subgroup analysis
The tests for subgroup differences performed for exercise-only 
interventions were not significant (see online supplementary 
figures 2–5).
Inadequate gestational weight gain
There was ‘low’ quality evidence from 15 RCTs (n=5858) 
regarding the association between prenatal exercise and 
IGWG.39 41–43 45 53 55 60–62 64–67 69 The quality of evidence was 
downgraded from ‘high’ to ‘low’ because of serious risk of bias 
and serious indirectness of the interventions. The pooled esti-
mate based on 12 RCTs (n=4848) showed 22% higher odds 
of IGWG with exercise compared with no exercise (OR 1.22, 
95% CI 1.03 to 1.45, I2=11%; figure 3).39 41–43 45 55 60–62 64–66 
Three RCTs could not be included in the meta-analysis (inter-
vention group, n=662; control group, n=348) and showed no 
increased odds of IGWG with prenatal exercise compared with 
no exercise (see online supplementary table 1). Jackson et al67 
reported that approximately 14% of the women in both the 
exercise + co-intervention (diet and behaviouralintervention) 
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Figure 3 Effects of prenatal exercise-only or exercise plus co-interventions compared with control on inadequate gestational weight gain (RCTs). 
Analyses conducted with a random effects model. df, degrees of freedom; M-H, Mantel–Haenszel method. NW: subgroup of women with normal 
weight; OW/OB: subgroup of women with overweight/obesity; OW: subgroup of women with overweight; OB: subgroup of women with obesity; 
Exercise: exercise arm of the intervention; Diet + exercise: diet + exercise arm of the intervention.
(n=158) and control groups (n=163) gained less than the GWG 
recommendations. Simmons et al69 and Vinter et al53 showed 
no increased odds of IGWG (ie, GWG 0 kg and >5 kg was also 
similar in both groups.76 Second, Ferrara et al59 reported 
no effect of a prenatal exercise + co-intervention (diet and 
behavioural intervention) on the odds of meeting postpartum 
weight loss goals (goal based on pre-pregnancy BMI) at 6 
weeks and 7 months postpartum. The results were the same 
when examining women with normal weight and those with 
overweight/obesity, or women who gained ≤ or >  IOM GWG 
recommendations.59 However, data at 12 months postpartum 
showed that women who gained ≤ IOM GWG recommenda-
tions and who participated in a prenatal exercise + co-inter-
vention were more likely to achieve weight loss goals than those 
who did not participate.59 Finally, a superiority trial showed 
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Figure 4 Effects of prenatal exercise-only or exercise plus co-interventions compared with control on postpartum weight retention (RCTs). Analyses 
conducted with a random effects model. df, degrees of freedom; IV, inverse variance; SD. Mean differences are in kg.
similar maternal weight retention at 2 months postpartum in 
both exercising groups (low-intensity exercise: 5.4±3.9 kg vs 
moderate-intensity exercise: 4.6±3.3 kg), as well as similar 
numbers of women with PPWR 5 kg at 12 months postpartum (OR 1.2, 
95% CI 0.41 to 3.51). Similarly, Phelan et al reported no effect 
of prenatal exercise + co-intervention (diet and behavioural 
intervention) on the odds of returning to pre-pregnancy weight 
at 12 months postpartum (OR 1.6, 95% CI 0.92 to 2.7).72 In 
contrast, Sagedal et al63 reported higher odds of returning to 
pre-pregnancy weight at 12 months postpartum (OR 1.50, 
95% CI 1.01 to 2.24) in women who participated in an exer-
cise + diet intervention. Similarly, Rauh et al reported lower 
odds of PPWR >5 kg at 4 months postpartum (OR 0.5, 95% CI 
0.2 to 0.9, adjusted for several potential confounding factors)55 
and at 12 months postpartum (OR 0.40, 95% CI 0.16 to 
0.97, adjusted for age, pre-pregnancy BMI, time of 12-month 
follow-up and practice)77 with a prenatal exercise + diet inter-
vention compared with no intervention. Finally, Seneviratne et 
al70 found that compliance with an exercise-only intervention 
(ie, the percentage of prescribed exercised sessions completed) 
was  associated  with  maternal  postnatal  BMI  (beta  −0.031, 
95% CI −0.059  to −0.002,  adjusted  for  ethnicity,  parity  and 
baseline BMI).
The results of the meta-regression analysis showed no dose–
response relationship between prenatal exercise and PPWR.
Sensitivity analysis
The pooled estimate for the exercise-only interventions was 
not significantly different from the pooled estimate for the 
exercise + co-interventions (P=0.87). Specifically, there was 
‘moderate’ quality evidence (downgraded due to serious risk 
of bias) showing that prenatal exercise-only interventions were 
associated  with  lower  PPWR  (three  RCTs,  n=420;  −0.92 kg, 
95% CI  −1.84  to  0.00 kg,  I2=0%; figure 4)44 45 70 compared 
with no exercise.
Subgroup analysis
The tests for subgroup differences performed for exercise-only 
interventions were not significant (see online supplementary 
figures 12–14).
The results for total GWG, GWG and weekly GWG during 
the intervention and AGWG are presented in the online supple-
ment. In summary, prenatal exercise was associated with lower 
total GWG compared with no exercise (59 RCTs, n=13 180; 
see online supplementary figure 15) and a dose–responserela-
tionship was found between prenatal exercise duration, frequency 
and volume and total GWG (see online supplementary figures 
39–42). Similarly, prenatal exercise was associated with lower 
GWG during the intervention (17 RCTs, n=2316; see online 
supplementary figure 20) and lower weekly GWG (five RCTs, 
n=1095; see online supplementary figure 24) compared with 
no exercise. Finally, there was a 39% greater odds of AGWG 
with exercise compared with no exercise (16 RCTs, n=5497; 
see online supplementary figure 26).
DIsCussIOn
In this comprehensive systematic review and meta-analysis of 
84 studies there was ‘moderate’ quality evidence indicating 32% 
decreased odds of EGWG with exercise-only interventions (15 
RCTs, n=3519).35–49 In order to achieve at least a 25% reduction 
in the odds of EGWG, pregnant women needed to accumulate 
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What is already known?
 ► Excessive (EGWG) and inadequate (IGWG) gestational weight 
gain (GWG) are associated with short- and long-term health 
issues for mother and child; promotion of adequate GWG 
(AGWG) is therefore of paramount importance.
 ► Prenatal exercise has been identified as an effective strategy 
to promote AGWG. However, a dose–response relationship 
between prenatal exercise and GWG is yet to be established.
 ► The long-term impact of prenatal exercise on body weight 
regulation during the postpartum period also needs to be 
clarified.
What are the new findings?
 ► Exercise-only interventions reduced GWG and PPWR by 
approximately 1.0 kg and decreased the odds of EGWG by 
32%.
 ► To achieve at least a 25% reduction in the odds of EGWG, 
pregnant women need to accumulate at least 456 MET-min/
week of moderate-intensity exercise (eg, 105 min/week of 
brisk walking, water aerobics, stationary cycling or resistance 
training).
 ► Our results suggest that a 25% increased risk of IGWG would 
be attained when exercise frequency exceeds four times/
week, exercise duration exceeds 40 min or exercise volume 
exceeds 550 MET-min/week. However, this result should be 
interpreted with caution because it was based on a limited 
number of studies (five RCTs).
at least 456 MET-min/week of moderate intensity exercise (eg, 
105 min of brisk walking, water aerobics, stationary cycling 
or resistance training per week). Results from meta-regression 
analyses suggested that prevention of EGWG was attained when 
exercise was performed at a frequency of at least 2 days per week 
and/or at least 35 min per session. Accumulating higher exercise 
volume was associated with a greater reduction in the odds of 
EGWG. EGWG is associated with long-term maternal and fetal 
overweight/obesity, cardiovascular morbidity and mortality.3 78–80 
Therefore, the observed 32% reduction in odds of EGWG indi-
cates that prenatal exercise may be an effective low-cost strategy 
to promote AGWG, and may have important implications for 
the long-term health of two generations. However, a better 
understanding of factors influencing the efficacy of prenatal 
exercise interventions targeting GWG in overweight and obese 
women is needed.
We also found ‘low’ to ‘moderate’ quality evidence indicating 
that exercise-only interventions were associated with a 1 kg reduc-
tion in both total GWG (28 RCTs, n=5819)35–37 41 43–45 47 49 70 81–98 
and PPWR (three RCTs, n=420).44 45 70 From a clinical stand-
point, a 1 kg difference in total GWG is small, and would only 
be meaningful if it was associated with higher adverse maternal 
and infant outcomes. Our data indicated higher odds of IGWG 
with prenatal exercise. A clinically meaningful increase in the 
odds of IGWG was attained when exercise volume exceeded 550 
MET-min/week. Our findings therefore suggest that women who 
accumulated at least 550 MET-min/week of moderate-intensity 
exercise had reduced odds of gaining excessively but also had 
increased odds of not gaining enough weight. It is important to 
note that the results for IGWG were only based on five studies. 
We must acknowledge the uncertainty around the meaningful-
ness of our findings, and the significant association we found 
between prenatal exercise and IGWG should be interpreted with 
caution. IGWG in these women may be the result of an imbal-
ance between caloric intake and energy expenditure, or medical 
management. Given that women who gain below GWG recom-
mendations have increased odds of SGA and preterm birth,2 
prenatal care providers should follow weight gain throughout 
pregnancy to ensure that women who are exercising during 
pregnancy gain appropriately, within the IOM guidelines. Coun-
selling about adequate nutrition and increasing awareness about 
the risk of IGWG is important.
Finally, although based on a limited number of studies, there 
was evidence that exercise-only interventions were associated 
with a reduction in PPWR, measured as early as 2 weeks post-de-
livery up until 1 year postpartum. Whether these findings are 
due to the benefit of prenatal exercise on reducing the odds of 
EGWG or to the long-lasting effect of prenatal exercise on body 
weight regulation during the postpartum period is unknown, 
since women who exercise during pregnancy are more likely to 
resume exercise in the postpartum period.99
There are several strengths of the current systematic review. 
Rigorous methodological standards (GRADE) were used to 
guide the systematic review process. This included searching 13 
databases for peer-reviewed literature as well as examining grey 
literature. The inclusion criteria were comprehensive, allowing 
inclusion of studies of all designs and published in three different 
languages. Data were combined by meta-analysis. Where it 
was not possible to include reported results in a meta-analysis, 
the results were still included and were synthesised narratively. 
Twenty-six countries from four continents were represented in 
the included studies. Subgroup analyses allowed identification 
of possible sources of heterogeneity in the effect of exercise-only 
interventions on total GWG; however, heterogeneity was still 
high within subgroups. A limitation of our study is that we were 
unable to examine the effect of different types of exercise such 
as resistance training alone on GWG, because there were few 
distinct types of exercise examined (only aerobic exercise or 
mixed exercise were examined). This highlights the need for 
future studies examining the effect of different types of exer-
cise (eg, aerobic vs resistance training) on GWG, as well as the 
efficacy of exercise interventions initiated during pregnancy to 
prevent EGWG and continued during postpartum to prevent 
weight retention, with a focus on women with overweight or 
obesity. More attention should be paid to monitoring and 
adequately reporting compliance with the exercise interventions 
as well as considering factors that may influence compliance 
and retention of study participants. Finally, no studies looked 
at the effect of exercising in different trimesters on the odds of 
EGWG. Given that the timing of EGWG has been reported to 
differentially affect fetal growth,100 101 future studies addressing 
this question are needed to establish the optimal time point to 
start an exercise intervention. Finally, we were unable to identifyevidence-based cut-off points for clinically meaningful changes 
in study outcomes. Accordingly, it is possible that the results may 
have over- or underestimated the relevance of the findings.
COnClusIOn
Exercise-only interventions were effective at lowering total 
GWG and PPWR, and reducing the odds of EGWG while 
increasing the odds of AGWG. However, the overall magnitude 
of GWG and PPWR difference between the intervention and 
control groups was quite small (1.0 kg) and the clinical relevance 
is unclear. We also found higher odds of IGWG with prenatal 
exercise, but this result needs to be considered with caution. To 
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achieve at least a 25% reduction in the odds of EGWG, preg-
nant women needed to accumulate at least 456 MET-min/week 
of moderate-intensity exercise.
Author affiliations
1Department of Human Kinetics, Université du Québec à Trois-Rivières, Trois-Rivières, 
Quebec, Canada
2R Samuel McLaughlin Foundation - Exercise and Pregnancy Laboratory, School of 
Kinesiology, Faculty of Health Sciences, Department of Anatomy and Cell Biology, 
Schulich School of Medicine and Dentistry, Children’s Health Research Institute, The 
University of Western Ontario, London, Ontario, Canada
3Program for Pregnancy and Postpartum Health, Faculty of Kinesiology, Sport, and 
Recreation, Women and Children’s Health Research Institute, Alberta Diabetes 
InstituteUniversity of Alberta, Edmonton, Alberta, Canada
4Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, 
UK
5Department of Anatomy, Universite du Quebec a Trois-Rivieres, Trois-Rivieres, 
Quebec, Canada
6Alberta Research Centre for Health Evidence, Faculty of Medicine and Dentistry, 
University of Alberta, Edmonton, Alberta, Canada
7School of Interdisciplinary Health Sciences, University of Ottawa, Ottawa, Ontario, 
Canada
8Healthy Active Living and Obesity Research Group, Children’s Hospital of Eastern 
Ontario Research Institute, Ottawa, Ontario, Canada
9Independent Researcher, Ottawa, Ontario, Canada
10Clinical Research Unit, Children’s Hospital of Eastern Ontario Research Institute, 
Ottawa, Ontario, Canada
11John W Scott Health Sciences Library, University of Alberta, Edmonton, Alberta, 
Canada
12School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, 
Ontario, Canada
13Department of Obstetrics and Gynecology, Queen’s University, Kingston, Ontario, 
Canada
14Facultad de Ciencias de la Actividad Física y del Deporte-INEF, Universidad 
Politécnica de Madrid, Madrid, Spain
Acknowledgements We would like to thank Bailey Shandro (UAlberta), 
Anne Courbalay (UQTR) and Meghan Sebastianski (Alberta SPOR SUPPORT Unit 
Knowledge Translation Platform), University of Alberta for their assistance with the 
meta-analysis. The authors wish to acknowledge Mary Duggan from the Canadian 
Society for Exercise Physiology who is one of the primary knowledge users. 
Contributors MHD, S-MR, MFM, GAD, KBA contributed to the conception of 
the study. MHD, S-MR, MFM, GAD, KBA, AJG, NB, VJP, CEG, LGS, RB contributed 
to the design of the study and development of the search strategy. LGS conducted 
the systematic search. FS, MJ, VM, RS, LR, MN, TSN, AW, AJK, AAM completed the 
acquisition of data. MHD, NB, MN performed the data analysis. All authors assisted 
with the interpretation. S-MR and MHD were the principal writers of the manuscript. 
All authors contributed to the drafting and revision of the final article. All authors 
approved the final submitted version of the manuscript.
Funding This project was funded by a Canadian Institute of Health Research 
Knowledge Synthesis Grant. MHD is funded by an Advancing Women’s Heart Health 
Initiative New Investigator Award supported by Health Canada and the Heart and 
Stroke Foundation of Canada. A-AM is funded by a Fonds de Recherche du Québec–
Santé Doctoral Research Award. RS is funded by a Canadian Institutes for Health 
Research Doctoral Research Award. 
Competing interests None declared.
Patient consent Not required.
Provenance and peer review Not commissioned; externally peer reviewed.
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