ECTS Abstracts (2015) 1 P256

Association between Amount of Exercises and Bone Mineral Density Changes During Pregnancy

William WK To1 & Margaret WN Wong2


1Dept of Obstetrics & Gynaecology, United Christian Hospital, Hong Kong, Hong Kong; 2Dept of Orthopaedics & Traumatology, the Chinese University of Hong Kong, Hong Kong, Hong Kong.


Background: The aim was to evaluate the association between bone mineral density (BMD) changes and amount of exercises during pregnancy in low risk women.

Methods: Consecutive patients were recruited from a general obstetric clinic over a period of 9 months. Quantitative USG measurements of BMD were performed at the os calcis bilaterally between 14-20 weeks, and at 36-38 weeks. A questionnaire survey was done on all recruited women at the time of the first BMD measurement. Categorizable exercises included brisk walking, jogging, yoga or Pilates, and formal sports activities. The average amount of exercises performed in the week prior to the survey was recorded.

Results: A total of 390 women were recruited, and the mean BMD loss from early to late pregnancy was 0.0301 g/cm2, SD 0.043. Within this cohort, 224 (57.4%)(Gp 1) reported exercising less than 1 hour per week, 94 (24%)(Gp 2) between 1-2 hours, 37 (9.5%)(Gp 3) between 2-3 hours, and 35 (8.9%) (Gp 4) reported excising for more than 3 hours. The mean BMD loss was 0.0368g/cm2 (SD 0.036), 0.0408 (SD 0.042), 0.0147 (SD 0.049) and -0.0247(SD 0.034), respectively for each group, indicating a trend from progressively lower BMD loss to a marginal positive gain with increasing exercise duration (P<0.005, ANOVA).

Conclusion: Mild to moderate exercises during early pregnancy of 2 to 3 hours per week at mid trimester and beyond were apparently protective against the physiological fall in BMD during pregnancy compared with those who were sedentary.

Disclosure: The authors declared no competing interests.

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