A claim you hear on longevity podcasts
The claim checked: Bed rest in pregnancy is bad, and exercise leads to better outcomes Hear it at 1:30:04
Eight of ten studies partly agreed. Exercise helped the mother in some ways, such as less gestational diabetes or less weight gain. Birth weight and other outcomes for the baby did not change. One review agreed in full, and one trial in Brazil found no benefit.
Computed from 10 studies that test this point, each judged by two readers, in full. 10 more studies are waiting for a full read and do not count yet.
“I think exercise is really important. The more data we get, the more we know like bed rest is bad. People do better when they exercise.”
systematic review · 2019 · landmark
“Strong evidence demonstrated that moderate-intensity physical activity reduced the risk of excessive gestational weight gain, gestational diabetes, and symptoms of postpartum depression.”
Benefits of Physical Activity during Pregnancy and Postpartum: An Umbrella Review. Med Sci Sports Exerc
Who: pregnant and postpartum women in systematic reviews and meta-analyses published 2006 to February 2018
PMID 31095086
pooled analysis · 2022 · landmark
“Diet was associated with improved maternal and neonatal outcomes, whereas physical activity was associated with improved adverse maternal outcomes.”
Association of Antenatal Diet and Physical Activity-Based Interventions With Gestational Weight Gain and Pregnancy Outcomes: A Systematic Review and Meta-analysis. JAMA Intern Med
Who: Pregnant women in antenatal RCTs of diet and/or physical activity interventions versus routine care across Europe, North America, Australia/New Zealand, UK, South America, Asia and the Middle East
PMID 34928300
controlled trial · 2016
“We found no difference in GWG between women randomized to an exercise training program versus standard maternity care, but found an apparent reduction in the incidence of GDM and lower systolic blood pressure in late pregnancy among the women randomized to the exercise training program.”
Exercise Training and Weight Gain in Obese Pregnant Women: A Randomized Controlled Trial (ETIP Trial). PLoS Med
Who: Pregnant women in Trondheim, Norway, with prepregnancy BMI >= 28 kg/m2, age >= 18 y, singleton, gestational week < 18, not habitually exercising
PMID 27459375
pooled analysis · 2017
“Diet and lifestyle interventions in pregnancy are clinically effective in reducing GWG irrespective of risk factors, with no effects on composite maternal and fetal outcomes.”
Effects of antenatal diet and physical activity on maternal and fetal outcomes: individual patient data meta-analysis and health economic evaluation. Health Technol Assess
Who: Pregnant women (excluding underweight) in randomized trials of diet-, physical activity- or mixed lifestyle interventions shared through the International Weight Management in Pregnancy Collaborative Network
PMID 28795682
pooled analysis · 2019
“Further, no significant mean difference was observed between vigorous intensity exercise and control groups on incidence of SGA, LBW, or maternal weight gain.”
The effects of vigorous intensity exercise in the third trimester of pregnancy: a systematic review and meta-analysis. BMC Pregnancy Childbirth
Who: Low-risk pregnant women doing vigorous-intensity exercise in the third trimester vs lower-intensity exercise or standard care (5 RCTs and 10 cohort/case-control studies)
PMID 31391016
controlled trial · 2011
“We did not find statistically significant differences between the two groups in mean birth weight, length, head circumference, and length of gestation, according to ITT-analysis.”
Exercise in pregnant women and birth weight: a randomized controlled trial. BMC Pregnancy Childbirth
Who: 105 healthy nulliparous, previously inactive pregnant women in Oslo, Norway, randomized within their first 24 weeks of pregnancy
PMID 21961534
pooled analysis · 2018
“The mean gestational age at delivery, birth weight, and the odds of cesarean section are similar in women who exercise regularly and women who receive routine prenatal care.”
The effect of exercise during pregnancy on gestational diabetes mellitus in normal-weight women: a systematic review and meta-analysis. BMC Pregnancy Childbirth
Who: Normal-weight (pre-pregnancy BMI 18.5-24.9) pregnant women in RCTs of exercise, all conducted in European countries
PMID 30419848
systematic review · 2008
“The results were conflicting for other outcomes, like miscarriage and gestational weight gain control.”
Physical activity during pregnancy and maternal-child health outcomes: a systematic literature review. Cad Saude Publica
Who: 37 observational studies (cohort, case-control, cross-sectional) of pregnant women published 1980-2005, mostly from the United States; sample sizes from 67 to 21,342
PMID 18797729
other primary study · 2009
“If on the one hand the present study failed to demonstrate any clear benefit to the mother practicing physical exercise in terms of a proportional reduction in fat mass, on the other hand, the safety of this practice is clearly demonstrated.”
Water aerobics II: maternal body composition and perinatal outcomes after a program for low risk pregnant women. Reprod Health
Who: Low-risk, sedentary pregnant women at 16-20 weeks of gestation attending a prenatal clinic in Campinas, Brazil
PMID 19126239
controlled trial · 2017
“This study did not support the benefits of exercise performed during pregnancy on preeclampsia, weight gain and gestational diabetes.”
A randomized controlled trial of exercise during pregnancy on maternal and neonatal outcomes: results from the PAMELA study. Int J Behav Nutr Phys Act
Who: 639 pregnant women aged 18+ in Pelotas, Brazil, not exercising >150 min/week, randomized at 16-20 weeks (213 exercise, 426 control) within the 2015 Pelotas Birth Cohort
PMID 29273044
Two of six studies found harm. In one, early birth was more common among women told to limit their activity. Four found bed rest did no good but did not measure harm.
Computed from 6 studies that test this point, each judged by two readers, in full. 10 more studies are waiting for a full read and do not count yet.
other primary study · 2013
“After controlling for potential confounding factors, preterm birth remained more common among those placed on activity restriction (adjusted odds ratio 2.37, 95% confidence interval 1.60–3.53).”
Activity restriction among women with a short cervix. Obstet Gynecol
Who: asymptomatic nulliparous women with singleton gestations and cervical length under 30 mm in a randomized trial of 17-alpha hydroxyprogesterone caproate
PMID 23812450
other primary study · 2020
“However, numerous reports have shown that activity restriction does not prevent adverse obstetrical outcomes but does confer significant physical and psychosocial risks.”
Society for Maternal-Fetal Medicine Consult Series #50: The role of activity restriction in obstetric management: (Replaces Consult Number 33, August 2014). Am J Obstet Gynecol
Who: Pregnant women prescribed activity restriction or bed rest (risk of preterm birth, multiple gestation, hypertension, PPROM, fetal growth restriction) in the trials, cohorts and Cochrane reviews summarized
PMID 32360110
pooled analysis · 2015
“There is no evidence, either supporting or refuting the use of bed rest at home or in hospital, to prevent preterm birth.”
Bed rest in singleton pregnancies for preventing preterm birth. Cochrane Database Syst Rev
Who: Women with singleton pregnancies at high risk of spontaneous preterm birth prescribed bed rest at home or in hospital vs no intervention or placebo
PMID 25821121
pooled analysis · 2010
“There is currently not enough evidence to support a policy of routine hospitalisation for bed rest in multiple pregnancy.”
Hospitalisation and bed rest for multiple pregnancy. Cochrane Database Syst Rev
Who: Women with a multiple pregnancy (twins or triplets) randomized to routine hospital bed rest versus selective admission; four of seven trials in Harare, Zimbabwe
PMID 20614420
other primary study · 2005
“The results of this trial and meta-analysis suggest no benefit of routine hospitalisation and bed rest for women with a triplet pregnancy in terms of reducing the risk of preterm birth and improving fetal growth.”
Hospitalisation for bed rest for women with a triplet pregnancy: an abandoned randomised controlled trial and meta-analysis. BMC Pregnancy Childbirth
Who: women with a triplet pregnancy at less than 24 weeks at one Australian hospital (7 women), pooled with one earlier trial (19 women)
PMID 15804370
controlled trial · 2026
“This study does not support the use of activity restriction in patients with an increased risk of preterm birth.”
Activity Restriction in Pregnancy and the Risk of Early Delivery: The AWARE Study. Obstet Gynecol
Who: pregnant patients with a short cervix on second-trimester ultrasound (singletons from TOPS, twins from PROSPECT) at US MFMU Network sites, wearing a wrist accelerometer
PMID 41712929
None.
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