Cramps are common in early pregnancy. They come from the implantation of the embryo into your uterus. They also occur because your uterus starts to grow fairly quickly in early pregnancy. Frequently, these feel like premenstrual cramps. You may experience compression type pain deep in your pelvis; it’s typically nothing to be worried about. A good index of pain severity is whether or not the pain keeps you up at night. If it does, that is usually the mark of more serious pain and you absolutely need to call your OB. However, anything that is on par with the typical menstrual cramps can usually be safely ignored.