When a woman is 38 weeks pregnant, the American Pregnancy Association states that cramping can be sign of labor if it is occurring at consistent intervals that ultimately get closer together. Many women describe contractions as feeling very similar to menstrual cramps.
When a women experiences cramping late in pregnancy, it is best if she makes notes about how long the cramping feeling is lasting and how often it is occurring. This can help her discern if the cramping is actually contractions. If the cramping is lasting for a minute and coming at 5 minute intervals, it is time to call the doctor.
Cramping is not always indicative of labor. It can also be a sign of a urinary tract infection, or it can be caused by the uterus expanding to make room for a rapidly growing baby. Some women find that drinking a tall glass of water and resting on the left side can help relieve cramps.