Can a pregnant woman get meningococcal vaccine?

No and Yes. Menactra (one brand) is a pregnancy catagory c, which means risk to fetus cannot be ruled out. Menveo is category b, which means there is no evidence of risk to fetus in humans. Therefore Menveo can be given to a pregnant mother, if/when the benefits outweigh the risks. However, neither is specifically indicated or thoroughly studied in pregnant women. Discuss you risks and benefits with doc.
See link. Here is what the centers for disease control say about the topic http://www.Cdc.Gov/vaccines/pubs/preg-guide.Htm#mening.