Our Patient
Rochelle began Cross-fit 5 years ago after her final season as a collegiate gymnast. She has remained consistent with it, even after she got a positive pregnancy test.
She presents in her second trimester of her first pregnancy. Aside from fatigue and nausea, her pregnancy has been uneventful. She wants to stay active and prepare delivery but has concerns about training at the same intensity as she progresses through her pregnancy.
This Week’s Articles:
Resistance training in pregnancy: systematic review and meta-analysis of pregnancy, delivery, fetal and pelvic floor outcomes and call to action
This systematic review from Prevett et al. (2025) evaluated the influence of resistance training (RT) during pregnancy on various pregnancy, delivery, fetal, and pelvic floor outcomes.
Methods
Inclusion criteria: Studies where pregnant individuals performed an RT (i.e. under an external load) of any intensity for at least 4 weeks, compared to usual care or non-RT interventions.
Exclusion criteria: Yoga and pilates due to the lack of an external load. Studies with acute or single-sessions of RT. Majority of the RT must occur on land.
Outcomes: Rates of pregnancy-related conditions (specifically gestational hypertension, pre-eclampsia, gestational diabetes, and peri-natal mood disorders) were the primary outcome measured. Other outcomes measured included delivery, fetal, and. pelvic-floor related outcomes.
50 studies (47,619 participants) were analyzed. Forty studies included RT as part of a multicomponent program involving aerobic exercise. Five studies had RT as the sole intervention. Pelvic floor muscle training was included in 18 of the studies. 43 of the studies met criteria for low or medium risk of bias.
Participants completed RT sessions 2-4 times a week with mostly low-to-moderate loads. A few studies looked at heavier loads (from anywhere between 30-80% of the participant’s 1 rep max). The RT component averaged between 10-25 minutes in duration. Reporting on specific RT loading and progression was noted as poor across the literature.
Results
RT was associated with a significant reduction in the odds of several complications:
Gestational hypertension (~58% decrease).
Gestational diabetes (~ 38% decrease)
Perinatal mood disorders (~52% decrease)
Macrosomia (~33% decrease)
RT did not significantly influence rates of the following:
Pre-eclampsia
Cesarean section
Gestational age at delivery
Instrumental delivery
Length of the second-stage of labor
Microsomia
Preterm delivery
Perineal tearing
Prevett, C., Gingerich, J., Sivak, A., & Davenport, M. H. (2025). Resistance training in pregnancy: systematic review and meta-analysis of pregnancy, delivery, fetal and pelvic floor outcomes and call to action. British journal of sports medicine, 59(16), 1173–1182. https://doi.org/10.1136/bjsports-2024-109123
Pushing limits: the acute effects of a heavy-load resistance protocol and supine exercise on fetal well-being
This experimental study assessed the acute effects of a heavy-load resistance protocol and supine exercise on fetal heart rate (FHR) and uteroplacental blood flow in active pregnant women.
Methods
Inclusion criteria: 48 healthy pregnant athletes (7 elite, 41 recreational) between 26–35 weeks gestation who regularly exercised at least 240 minutes per week.
Exclusion criteria: Any participant experiencing medical or obstetrical contraindications to exercise.
Measurements: FHR and pulsatility index (PI) of the umbilical and uterine arteries were measured via ultrasound at baseline and within 30 seconds after each exercise by an OBGYN specializing in maternal-fetal medicine.
Intervention: On the first day, participants completed a submaximal high-intensity interval session (5x5 minute intervals) on a treadmill at 90% of maximal maternal heart rate and a 17 on the Borg RPE scale. One to two days later, participants performed a second interval session on a cycle ergometer and then 20 minutes later followed with a heavy-load RT protocol.
After a warm up, 3x8 repetitions with one repetition in reserve (approx. 76% 1RM) in sumo deadlift, bench press, and incline bench press (with a 30 degree bench angle). A 90 second rest period followed each set.
Within 30 seconds of completing 3 sets of each exercise, ultrasound measurements were performed. Researchers would ask participants “Did the exercise make you feel dizzy, light-headed, nauseous, or otherwise unwell?” to screen for vena cava syndrome.
Results
FHR remained within normal ranges (110–160 bpm) for most participants, with significant increases post-sumo deadlift and post-incline bench press. None of the increases in FHR reached pathologic levels.
Uterine artery PI significantly decreased after all exercises, indicating that blood flow was not compromised.
Umbilical artery PI remained unchanged from base-line to post-exercise
• One transient case of fetal bradycardia occurred after the bench press but resolved within 3 minutes. During that time uterine artery PI increased.
• Only one participant experienced dizziness during supine exercise, while FHR remained stable and the umbilical artery PI decreased (which indicates improved fetal perfusion). The participant’s symptoms resolved upon sitting up.
• Fetal responses were more stable in women with regular heavy-load training experience.
Dalhaug, E. M., Sanda, B., Bø, K., Brown, W., & Haakstad, L. A. H. (2025). Pushing limits: the acute effects of a heavy-load resistance protocol and supine exercise on fetal well-being. BMJ Open Sport & Exercise Medicine, 11, e002639. https://doi.org/10.1136/bmjsem-2025-002639
Applying the findings
RT during pregnancy is safe and highly beneficial to maternal and fetal well-being. Although the literature supporting the use of RT in a pregnant population continues to emerge, the current lack of research is not evidence of harm. The majority of research follows low intensity guidelines that may lead to unnecessary deconditioning.
Despite the lack of research supporting heavy load RT, the research available supports RT decreases the odds of gestational hypertension, gestational diabetes, macrosomia, and perinatal mood disorders. Additionally, there is no evidence that RT significantly affects the odds of pre-eclampsia, cesarean section delivery, instrument-assisted delivery, pre-term delivery, perineal tearing, microsomia, the length of the second-stage of labor, or the gestational age at delivery.
Pregnant women with a history of RT can safely perform heavy-load RT (such as ~ 76% of 1 rep max). The pregnant body can adjust to the loads applied to it without harming the fetus if the pregnant person had a history of resistance training prior to pregnancy.
Some pregnant women may be able to perform supine exercises (such as a bench press), but they should also be monitored for signs and symptoms of vena cava syndrome (dizziness, nausea, pale skin, sweating, et c.). These findings should not be extrapolated to women with heavy-load resistance training from an occupational setting as the total loads and rest breaks are not the same as those with structured resistance training programs.
