Though cramping is often a sign of menstruation, it can also be a symptom of other occurrences within the female body. For example, one major reason for cramping but no period is pregnancy, as sudden cramping and the lack of a period are often the very first signs of conception. Ovulation pain is another common reason for cramping without getting a period, since the period usually comes about two weeks after ovulation. The combination of gas or constipation, and either physical or mental distress can also result in cramps and the absence of a period.
There are a few reasons for cramping but no period during pregnancy. Once conception has occurred, the presence of certain hormones signals the body to keep the uterine lining intact instead of shedding it, which is why the period usually does not show up during pregnancy. Cramping often ensues as the embryo implants in the uterus, and it is usually called implantation cramping. While menstruation does not typically take place during pregnancy, implantation can cause spotting or even light bleeding as the embryo burrows deep into the lining, but it is usually so slight that few women notice it. Weeks into the pregnancy, the uterine muscles typically must contract to begin expanding in preparation for the growing fetus, which is another cause of cramping during pregnancy.
In some cases, cramping but no period can actually signal ovulation, which means that the body is just at another point in the menstrual cycle. Ovulation usually occurs about two weeks before the menstrual period shows up, during which time some women feel cramping on one side of the body. The cramping usually signals the release of the egg from the ovary, and typically lasts anywhere from a few hours to a couple of days. Not every woman has a regular cycle, which means that the period and ovulation may be late, early, or nonexistent that month. This leads to some women miscalculating the expected start of their menstruation, resulting in worry over experiencing cramping but no period, when it is not even due yet.
Some reasons for experiencing cramping but no period involve areas of the body besides the reproductive system. For example, gas and constipation can result in painful cramps in the lower abdomen, typically confusing those who are not used to discomfort brought on by these issues. Of course, gas does not usually delay the period's arrival, but stress can. In fact, mental stress is just one issue that causes the period to be late, as physical stress on the body due to obesity, malnourishment, or a sudden extreme exercise program can also distress the body enough to skip a period.