All six of the top-ranked wrestlers from the November rankings have retained the No. 1 positions in the most recent TheMat.com  U.S. Women's Wrestling College Rankings, released Dec. 20.    Four of the top-ranked wrestlers competed for the United States at the Women's World Championships in Sofia, Bulgaria, Nov. 22-25.    Cumberland College freshman Toccara Montgomery, ranked No. 1 at 149.75 pounds, claimed a silver medal for the United States at the World Championships. Freshman Jenna Pavlik of Lock Haven, ranked No. 1 at 165.25 pounds, placed fifth for the United States at the World Championships.    Two other top-ranked Lock Haven wrestlers, freshman Erin Tomeo at 123 pounds and senior Sara McMann at 136.5 pounds, also represented the United States at the World Championshipos in Bulgaria.    The other two top-ranked wrestlers from November maintained their No. 1 position in the December ranking:  junior Clarissa Chun of Missouri Valley at 101.25 pounds and Stanford senior Patricia Miranda at 112.25 pounds. Both were members of the 2000 U.S. Women's World Team.    The top six teams in the November rankings also held their spots in December: No. 1 Missouri Valley College, No. 2 Lock Haven, No. 3 UM-Morris, No. 4. Pacific, No. 5 Cumberland College and No. 6 Neosho County. Missouri Valley defeated Neosho in its first U.S. dual meet of the new season, and Cumberland also scored a victory over Neosho.    Moving up to the No. 7 position from the No. 8 spot was American International College of Massachusetts, which had some strong individual accomplishments at the Brock Invitiational in Canada in late November.     FILA, the international wrestling federation, has changed the women's weight classes for the Senior level, starting with January 2002. The new weight classes will be 48 kg (105.6 lbs.), 51 kg (112.2 lbs.). 55 kg (121 lbs.), 59 kg (129.8 lbs.), 63 kg (138.6 lbs.), 67 kg (147.4 lbs.), 72 kg (158.4 lbs.). TheMat.com will use these new weight classes for the college rankings starting with the next ranking on January 20.    Complete individual and team rankings are posted on TheMat.com, in the rankings section.    TheMat.com U.S. College Women's Wrestling rankings will be published monthly on the following dates: Oct. 20, Nov. 20, Dec. 20, Jan. 20, Feb. 20, March 20, April 20, May 20.    Teams who are considered for ranking include both college varsity programs and college-affiliated club programs.    Athletes who are considered for ranking are eligible full-time college students, and are members of their college women's varsity or club program, or a member of their college men's wrestling team.     TheMat.com has created a composite schedule for women's college wrestling, which includes events from the U.S. and Canadian programs. Results from these events will be posted on a regular basis throughout the season.    Media outlets may reproduce these rankings only if they identify them as TheMat.com U.S. Women's Wrestling College Rankings