Eighteen weeks pregnant suddenly feel a hard lump in the right abdomen may be the cause of pregnancy uterus, fibroids, ovarian cysts. 1. pregnancy uterus: normal pregnancy uterus in 18 weeks of pregnancy uterus bottom in the umbilicus about 2 fingers, when the fetus moves, long time standing under the situation of bleeding pseudo-contraction, easy to touch the hard lump in the lower abdomen. No pressure pain. 2. Uterine fibroids: pregnancy combined with uterine fibroids, the location of subplasma fibroids with the uterus increases, can be touched in the 18th week of pregnancy in the uterine surface with hard lumps, no pressure and pain. There are no accompanying symptoms such as vaginal bleeding. 3. Ovarian cysts: when pregnancy is combined with ovarian cysts, the position of ovarian cysts will be elevated after the uterus enlarges. At 18 weeks of pregnancy, ovarian cysts can be detected in the right lower abdomen, with light border and no pressure pain. Most of the hard lumps in the right lower abdomen at 18 weeks of pregnancy are enlarged uterus, if there is any abnormality, consult the doctor in time to find out the cause under the doctor’s guidance and give appropriate treatment.