The most common obstetric causes of pelvic pain during early pregnancy are The normal changes of pregnancy Spontaneous abortion (threatened, inevitable, incomplete, complete, septic, or missed) The most common serious obstetric cause is Ruptured ectopic pregnancy Nonobstetric gynecologic causes include adnexal torsion, which is more common during pregnancy because during pregnancy, the corpus luteum causes the ovaries to enlarge, increasing the risk of the ovary twisting around the pedicle.