There has been a lack of agreement on the variation in and the correlates of menstrual cycle length in the literature. A total of 2566 wom en from rural and urban areas in one district of Tamil Nadu in southern India were studied prospectively to identify correlates of menstrual cycle length. Rural women had higher odds for short and for long cycle lengths. Younger women, those with higher age at marriage, and those with lower educational status had significantly longer cycle lengths.
Jeyaseelan, L and Rao, P. S. S.
"Correlates of Menstrual Cycle Length in South Indian Women: A Prospective Study,"
4, Article 6.
Available at: http://digitalcommons.wayne.edu/humbiol/vol65/iss4/6