The effect of pregnancy and the duration of postpartum convalescence on the physical fitness of healthy women: A cohort study of active duty servicewomen receiving 6 weeks versus 12 weeks convalescence

Abstract

Introduction: Pregnancy profoundly affects cardiovascular and musculoskeletal performance requiring up to 12 months for recovery in healthy individuals.

Objective: To assess the effects of extending postpartum convalescence from 6 to 12 weeks on the physical fitness of Active Duty (AD) soldiers as measured by the Army Physical Fitness Test (APFT) and Body Mass Index (BMI).

Methods: We conducted a retrospective study of AD soldiers who delivered their singleton pregnancy of ≥ 32weeks gestation at a tertiary medical center. Pre- and post-pregnancy APFT results as well as demographic, pregnancy, and postpartum data were collected. Changes in APFT raw scores, body composition measures, and failure rates across the 6-week and 12-week convalescent cohorts were assessed. Multivariable regressions were utilized to associate risk factors with failure.

Results: Four hundred sixty women met inclusion criteria; N = 358 in the 6 week cohort and N = 102 in the 12 week cohort. Demographic variables were similar between the cohorts. APFT failure rates across pregnancy increased more than 3-fold in both groups, but no significant differences were found between groups in the decrement of performance or weight gain. With the combined cohort, multivariable regression analysis showed failure on the postpartum APFT to be independently associated with failure on the pre-pregnancy APFT (OR = 16.92, 95% CI 4.96-57.77), failure on pre-pregnancy BMI (OR = 8.44, 95% CI 2.23-31.92), elevated BMI at 6-8 weeks postpartum (OR = 4.02, 95% CI 1.42-11.35) and not breastfeeding at 2 months (OR = 3.23, 95% CI 1.48-7.02). Within 36 months of delivery date, 75% of women had achieved pre-pregnancy levels of fitness.

Conclusion: An additional 6 weeks of convalescence did not adversely affect physical performance or BMI measures in AD Army women following pregnancy. Modifiable factors such as pre- and post-pregnancy conditioning and weight, weight gain in pregnancy and always breastfeeding were found to be significant in recovery of physical fitness postpartum.

Conflict of interest statement

No authors have competing interests.

Figures

Fig 1. Selection of study participants.

APFT, Army Physical Fitness Test. * Inclusion criteria are U.S. Army Servicewomen; delivery of pregnancy at Tripler Army Medical Center; delivery between January 1, 2011 and March 31, 2017; and gestational age at delivery greater than or equal to 32 completed weeks. # Exclusion criteria are duplicate record; multiple gestation; parity of three or more. ## Incomplete APFT record included last pre-pregnancy APFT more than 15 months before new obstetric appointment or record of 1st postpartum APFT more than 15 months after delivery in the Digital Training Management System.

Fig 2. Army Physical Fitness Test (APFT) and body composition failure rates.

* P

Fig 3. Postpartum APFT event raw scores and overall scores over time.

APFT, Army Physical Fitness Test. Pre- denotes the last pre-pregnancy APFT. * P

Fig 4. Kaplan-Meier estimates of time to achieve postpartum individual APFT event and overall APFT score equal to or greater than the last pre-pregnancy APFT.

APFT, Army Physical Fitness Test.