As your pregnancy progresses, your abdomen begins to enlarge and the weight of the enlarged uterus starts creating pressure on the organs around it. In fact, if the pressure is extreme, your sciatic nerve might get over stretched, resulting in a strain and thereafter excruciating pain. As your pelvis relaxes and stretches, you may also experience pain in the lower abdomen and a constant feeling of pressure.
Pelvic pressure usually seems like pain that originates in the pelvic region and continues down the thighs and the legs. If the ligaments that are supporting your uterus stretch, it may cause sharp pains.
You may apply heat to dull the pain that you experience. If you are lying still and the pain is growing, try changing your position, allowing the baby to move and shift the pressure. A lot of women rock their pelvis to ease the pressure. Alternately, you can also do a double hip squeeze. If the pressure becomes unbearable, talk to your doctor about it.