Abstract, below, which may be of interest.
regards,
Kate

Physical Activity and Mood during Pregnancy
This study compares three physical activity (PA) measures in pregnant
women and examines the mood correlates of physical activity changes
during pregnancy.
Med Sci Sports Exerc 37(8) 2005

Abstract:

Purpose: To compare three physical activity (PA) measures in pregnant women
and examine mood correlates of physical activity changes during pregnancy.
Methods: A sample of 12 pregnant women (PW) was recruited during their
first trimester and 12 nonpregnant women (NPW) (baseline age = 30.7 ± 4.4
yr) were matched to the PW (29.8 ± 4.2 yr). Once monthly, for seven
consecutive months, total weekly energy expenditure (TWEE) was assessed
using a physical activity diary (PAD) and a recall interview (PAR).
Accelerometers were worn for 3 d each month. Mood was also assessed. A
two-factor mixed-model ANOVA was used to analyze the data (2 groups [PW vs
NPW] x 7 times across pregnancy).
Results: Mean PAR TWEE and daily mean MTI counts were positively and
moderately correlated with mean PAD TWEE (PW: r = 0.40 and NPW: r = 0.50, P
< 0.001). The MTI counts decreased significantly in PW by 23% from
gestational weeks 12 to 36 compared with a 5% decrease in NPW. Fatigue and
vigor scores improved from gestational weeks 12 to 16 and worsened from
weeks 32 to 36 in PW. Changes in PA were not correlated to changes in mood
in either group.
Conclusions: The results provide some evidence for the validity of the 7-d
PAR and accelerometer as measures of physical activity in pregnancy.
Healthy women who maintain an above average level of physical activity
during the second and third trimesters can enjoy mood stability.

Full article (available with Medscape membership):
http://mp.medscape.com/cgi-bin1/DM/y/etfV0Jgw360D2s0GwTV0E8