[Prevalence of calf muscle cramps and influencing factors for pregnant women in China during 2010-2012].

To investigate the prevalence of calf muscle cramps and possible influencing factors for pregnant women in China. Using a multi-stage stratified probability proportional to size cluster randomization sampling method during 2010-2012. A total of 3 582 pregnant women were investigated at 150 counties from 31 provinces in China mainland. Information on calf muscle cramps, demographic socio-economic status, pregnancy information, and the physical activities was collected through questionnaires. The semi-quantitative food frequency questionnaire (FFQ) was used to collect food intake of pregnant women. Dynamic cluster analysis was used to assess dietary pattern. Multiple logistic regression was used to investigate the possible influencing factors for calf muscle cramps. The prevalence of calf muscle cramps was 32.9% (1 180/3 582) in Chinese pregnant women, which was 11.6% (87/748), 28.2% (420/1 492), and 50.2% (673/1 342), respectively, during the first, second and third trimester. There were significant differences between them (χ(2)=349.16, 0.001). Dietary patterns of the pregnant women were classified into three groups, which called relatively balanced pattern, high vegetables and fruits pattern, and high dairy pattern. Among the three groups, the prevalence of calf muscle cramps was 32.0% (952/2 971), 37.2% (186/500), and 37.8% (42/111), with significant differences (χ(2)=6.39, 0.041). The (95) values of calf muscle cramps in the second and third trimester was 2.96 (2.28-3.83), and 8.02 (6.16-10.44), respectively, comparing with the first trimester. The (95) values of calf muscle cramps in the women taking calcium before pregnant was 1.45 (1.19-1.76), comparing with the one who was not taken. The (95) values of calf muscle cramps in the women who had been diagnosed by pregnancy-induced hypertension was 5.76 (2.06-16.12), comparing with the one who had not been diagnosed. The (95) values of calf muscle cramps in the high vegetables and fruits pattern and high dairy pattern was 1.13 (0.91-1.41), and 1.18 (0.76-1.81), respectively, comparing with the relatively balanced pattern. The prevalence of calf muscle cramps was relatively high in Chinese pregnant women, which was significantly different among three trimesters. The residential areas, occupation, and pregnancy-induced hypertension might be related to the prevalence of calf muscle cramps. However, there was no significant difference among different dietary patterns.