The participating HDAC inhibitor centres were required to offer routine antenatal care and have facilities

to allow the conduct of a supervised exercise class. Participants in the experimental group were invited to participate in three 60-min exercise classes per week, starting between week 16 and 20 of gestation and continuing for 3 months. All subjects wore a heart-rate monitor during the training sessions to ensure that exercise intensity was moderate to vigorous (Ramírez-Vélez et al 2009, Ramírez-Vélez et al 2011b). Sessions consisted of walking (10 min), aerobic exercise (30 min), stretching (10 min), and relaxation (10 min). Aerobic activities were prescribed at moderate to vigorous intensity, aiming for 55–75% of maximal heart rate and adjusted according to ratings on the Borg scale (Borg, 1982). Adherence to the exercise program was encouraged by the physiotherapist

who supervised the exercise sessions. In order to maximise adherence to the training program, all sessions were: supervised by a physiotherapist and a physician, conducted in groups of three to five women, accompanied by music, BVD-523 cell line and performed in a spacious, airconditioned room. The control group received no exercise intervention, did not attend the exercise classes, and did not take part in a home exercise program. Both groups continued with their normal prenatal care (1 session per week for 3 months) and physical activity. One day before beginning the exercise program and immediately after the 3-month exercise period finished, all women were assessed for symptoms of depression using the Center

for Epidemiological Studies-Depression Scale (CES-D). The 20-item scale has adequate test-retest reliability, internal consistency, and concurrent validity (Wells et al heptaminol 1987). Test-retest reliability over a one-month period on this sample was 0.79, suggesting some shortterm stability of depressive symptoms. A score of 16 on the CESD is considered the cut-point for depression (Radloff and Rae, 1979). We sought to detect a between-group difference in the change in the CES-D score of 4 points as we considered this a clinically important improvement in depressive symptoms. Assuming that the standard deviation in this score would be 6, similar to that observed in a similar sample of women during pregnancy (Carter et al 2000), a total sample size of 74 would provide 80% power to detect a difference of 4 points as statistically significant. We recruited additional participants to allow for withdrawals. Data were entered in an electronic database by investigators at the time of assessment. Random checks of data entry were performed and corrections made where possible by phoning participants for confirmation.