Avoiding single mothers is a given. However you should also avoid women who have been previously married

50% of marriages end in divorce. 70% of people who marry a second time will have a second divorce. Women who have been through a divorce are 20% more likely to divorce you. Do not date previously married women. They already know how the family court system works and they have already proven that they don't value marriage.

But in reality you should avoid all women.