Pregnant Women Doing Resistance Exercise Training (PREG_RET)

Experiences by Pregnant Power Athletes, and Health Related Outcomes in Mother and Infants, After Resistance Exercise Training During Pregnancy

Despite the increase in numbers of women who engage in heavy, free-weight resistance exercise training (e.g. powerlifting, weightlifting, cross fit), the knowledge on how such exercise may affect fertility, pregnancy and birth outcomes is poor. Based on observational and associational studies of pregnant women in labour, recommendations are not to lift more than 11 kg in external load after mid-term, or to lift more than a total of 100 kg during a day. Ignoring such recommendations is associated to increased risk of miscarriage and preeclampsia, and of low birthweight and premature birth, respectively. As such, fit women who continue to exercise during pregnancy, are met with scepticism and warnings, resulting in shame and insecurity. Such attitudes may also result in physical inactivity during pregnancy, being on the contrary of what is recommended for a healthy pregnancy and delivery. Elite athletes may additionally be deprived from an early return to sport if not being able to keep exercise intensity close to pre-pregnancy period. With poor knowledge on how fit, strong women respond to high external loads during pregnancy exercise, recommendations are to follow the general guidelines.

The aim of this observational study, is to explore how regular resistance exercise training may affect fertility, and how high external loads in resistance exercise training during pregnancy in resistance trained women affect; a)their pregnancy and birth outcome, and b)health of the women and their children up to 12 months post-delivery.

Study Overview

• Status: Completed
• Conditions: Pregnancy Related

Detailed Description

Pregnant women who are experienced in heavy, free-weight resistance exercise training, and who choose to continue their exercise regimes during pregnancy, are recruited in social media to regularly respond to an online questionnaire on personal health, foetus development, and the newborn child health.

A reference group of pregnant women being regularly physical active (still not lifting free weights of high loads) are concurrently recruited.

All will respond to questionnaire at mid-term, and week 23, 30 and 40 of pregnancy. During maternity leave the women will be asked to respond to questionnaires at 1 month, 3 months, 6 months and 12 months post-delivery.

• Study Type: Observational
• Enrollment (Actual): 53

Contacts and Locations

Study Locations

• Norway
  • Fredrikstad, Norway, 1671
    • Therese Fostervold Mathisen

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 45 years (Adult)
• Accepts Healthy Volunteers: Yes

• Sampling Method: Probability Sample

Study Population

Women included in "group of interest" are pregnant women who are experienced in heavy, free-weigth resistance exercise training (i.e. powerlifter, weightlifter, cross fit) who aim to continue exercise training during pregnancy.

Reference group are pregnant women with no experience in heavy, free-weight resistance exercise, but who are regurlarly physically active in any sport activity (at least 2 times per week), and who aim to continue to exercise during pregnancy.

Description

Inclusion Criteria:

• Being pregnant
• Group of interest: Being experienced with heavy, free-weight resistance exercise training, and aiming to continue exercise at comparable level during pregnancy
• Reference group: being regularly physical active before pregnancy (i.e. at least 2 work- outs per week), but not experienced in heavy, free-weight resistance exercise training

Exclusion Criteria:

• Any known metabolic condition or contraindication on doing physical activity during pregnancy (i.e. miscarriages, bleedings).

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
Weight lifting women; Experienced resistance exercise trained and pregnant women
Reference women; Physically active pregnant women (not experienced with free weight lifting)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Delivery week	The selfreported pregnancy week for delivery	At delivery time
Delivery method	Participants report the method for delivery, choosing from natural delivery, delivery with assistance (e.g. birth forceps, vacuum delivery), caesarean section.	At delivery time
Pregnancy complications at week 23	Number of participants who report any complications during pregnancy, choosing from a list of alternatives (yes/no) (preeclampsia, nausea, fatigue, low back pain, pelvic pain, constipation, mood swings, birth anxiety, gestational depression, anemia, hypertension, pregnancy diabetes, foetus growth retardation)	During pregnancy up to week 23
Pregnancy complications at week 30	Number of participants who report any complications during pregnancy, choosing from a list of alternatives (yes/no) (preeclampsia, nausea, fatigue, low back pain, pelvic pain, constipation, mood swings, birth anxiety, gestational depression, anemia, hypertension, pregnancy diabetes, foetus growth retardation)	Pregnancy week 23 to 30
Pregnancy complications at week 40	Number of participants who report any complications during pregnancy, choosing from a list of alternatives (yes/no) (preeclampsia, nausea, fatigue, low back pain, pelvic pain, constipation, mood swings, birth anxiety, gestational depression, anemia, hypertension, pregnancy diabetes, foetus growth retardation)	Pregnancy week 30 to 40
Childs weight at birth	The weight of the child	At delivery time
Childs length at birth	The length of the child	At delivery time
Apgar score 5 minutes	The Apgar score 5 minutes post-delivery. This test checks a baby's heart rate, muscle tone, and other signs to see if extra medical care or emergency care is needed. The test is usually given twice: once at 1 minute after birth, and again at 5 minutes after birth. Scores below 4 indicates need for lifesaving measures, and higher scores indicates better health.	At delivery time (5 minutes post-delivery)
Miscarriage	Number of miscarriages	Previous and up to October 2023
Urinary incontinence before pregnancy	Number of participants reporting any challenges with urinary incontinence, and if it occurs; if it is only during increased abdominal pressure (coughing, laughing), or heavy lifting (choosing from a list of "always", only during increased abdominal pressure, only during lifting of heavy load)	Any experience before pregnancy
Urinary incontinence during pregnancy	Number of participants reporting any urinary incontinence, and if it occurs; if it is only during increased abdominal pressure (coughing, laughing), or heavy lifting (choosing from a list of "always", only during increased abdominal pressure, only during lifting of heavy load)	At pregnancy week 23, 30 and 40
Urinary incontinence after delivery	Number of participants reporting any urinary incontinence, and if it occurs; if it is only during increased abdominal pressure (coughing, laughing), or heavy lifting (choosing from a list of "always", only during increased abdominal pressure, only during lifting of heavy load)	Post-delivery: 1 month-, 3months-, 6 months- and 12 months
Anal insufficiency before pregnancy	Number of participants reporting any challenges with fecal incontinence	Any experience before pregnancy
Anal insufficiency during pregnancy	Number of participants reporting any challenges with fecal incontinence	At pregnancy week 23, 30 and 40
Anal insufficiency after delivery	Number of participants reporting any fecal incontinence and if it has worsened after giving birth	Post-delivery: 1 month-, 3months-, 6 months- and 12 months
Injuries during pregnancy up to week 23	Number of participants reporting on any exercise related injuries occuring during pregnancy, choosing from a list of anatomical locations	During pregnancy up to week 23
Injuries during pregnancy, up to week 30	Number of participants reporting on any exercise related injuries occuring during pregnancy, choosing from a list of anatomical locations	Pregnancy week 23 to 30
Injuries during pregnancy, up to week 40	Number of participants reporting on any exercise related injuries occuring during pregnancy, choosing from a list of anatomical locations (yes/no)	Pregnancy week 30 to 40
Analgesic during delivery	Number of participants reporting use of analgesic during delivery, and what type of analgesic (e.g. nitrous oxide, epidural)	At delivery time

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Body weight at week 23	Participants report on body weight changes during pregnancy	Pregnancy week 23
Body weight at week 30	Participants report on body weight changes during pregnancy	Pregnancy week 30
Body weight at week 40	Participants report on body weight changes during pregnancy	Pregnancy week 40
Body weight post-delivery, 1month	Participants report on body weight changes after pregnancy	Postpartum, 1 month after delivery
Body weight post-delivery, 3 months	Participants report on body weight changes after pregnancy	Postpartum, 3 months after delivery
Body weight post-delivery, 6 months	Participants report on body weight changes after pregnancy	Postpartum, 6 months after delivery
Body weight post-delivery, 12 months	Participants report on body weight changes after pregnancy	Postpartum, 12 months after delivery
Changes in external loads used in exercise training	Participants report on changes in external loads used in exercise during pregnancy (% of normal loading used pre-pregnancy)	During pregnancy
Changes in external loads used in exercise training, up to week 23	Participants report on changes in external loads used in exercise during pregnancy (% of normal loading used pre-pregnancy)	During pregnancy, week 23
Changes in external loads used in exercise training	Participants report on changes in external loads used in exercise after pregnancy (% of normal loading used pre-pregnancy)	Post-delivery: 1 month-, 3months-, 6 months- and 12 months
Changes in exercise volume during pregnancy, up to week 23	Participants report on changes in exercise volume (number of sessions per week) during pregnancy	During pregnancy, week 23
Changes in exercise volume during pregnancy, up to week 30	Participants report on changes in exercise volume (number of sessions per week) during pregnancy	During pregnancy, week 30
Changes in exercise volume during pregnancy, up to week 40	Participants report on changes in exercise volume (number of sessions per week) during pregnancy	During pregnancy, week 40
Changes in exercise volume after pregnancy	Participants report on changes in exercise volume (number of sessions per week) after pregnancy	Post-delivery: 1 month-, 3months-, 6 months- and 12 months
Injuries from exercise during maternity leave	Reporting on any exercise related injuries occuring during maternity leave (up to 12 months post-delivery), choosing from a list of anatomical locations	Post-delivery: 1 month-, 3months-, 6 months- and 12 months
Fertility	Reports on any fertility problems or use of fertility techniques in order to become pregnant	Before pregnancy
Bloodpressure	Bloodpressure measures, and numbers above/below clinical cut offs (having hypo-or hypertension)	At pregnancy week 23, 30 and 40, and at 1 month-, 3months-, 6 months- and 12 months postdelivery,
Symphysis-fundus measure	symphysis fundus measure during pregnancy; as a measure for growth of the fetus, evaluated according to national/international standards	At pregnancy week 23, 30 and 40

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Use of supplements	Number of participants reporting use of dietary supplements, and what kind of supplements	At pregnancy week 23, 30 and 40, and at 1 month-, 3months-, 6 months- and 12 months postdelivery,
Use of caffein (coffee, energydrinks, sodawater)	Number of participants reporting use of caffein, and in what doses per day	At pregnancy week 23, 30 and 40, and at 1 month-, 3months-, 6 months- and 12 months postdelivery,
Intake of alcohol	Number of participants reporting intake of alcohol, and how regularly (choosing between no, daily, weekly, monthly)	At pregnancy week 23, 30 and 40, and at 1 month-, 3months-, 6 months- and 12 months postdelivery,
Use of tobacco/cigarettes or snus	Number of participants reporting any use	At pregnancy week 23, 30 and 40, and at 1 month-, 3months-, 6 months- and 12 months postdelivery,
Use of any prescribed drugs	Number of participants reporting any use, and what type of drug	At pregnancy week 23, 30 and 40, and at 1 month-, 3months-, 6 months- and 12 months postdelivery,

Collaborators and Investigators

• Sponsor: Ostfold University College
• Investigators: Principal Investigator: Therese F Mathisen, PhD, Østfold University College

Study record dates

Study Major Dates

• Study Start (Actual): November 1, 2020
• Primary Completion (Actual): June 25, 2023
• Study Completion (Actual): June 25, 2023

Study Registration Dates

• First Submitted: October 10, 2020
• First Submitted That Met QC Criteria: March 1, 2021
• First Posted (Actual): March 3, 2021

Study Record Updates

• Last Update Posted (Actual): April 2, 2024
• Last Update Submitted That Met QC Criteria: April 1, 2024
• Last Verified: April 1, 2024

More Information

Terms related to this study

• Keywords: Pregnancy; Delivery; Fertility; Resistance exercise training; Powerlifting; Weightlifting; Female athlete; Maternity leave
• Other Study ID Numbers: 170066

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Data are kept within the research group

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No