Ultrasound is the preferred test for evaluation in early pregnancy. Often this is done for pelvic pain and spotting. Pelvic pain is a non specific symptom in early pregnancy. The main goals are to ensure that the pregnancy is viable and that it is in the uterine cavity and not ectopic. Pelvic pain in early pregnancy can be caused by many conditions to include normal development of the pregnancy.
An important condition that needs to be excluded when there is pelvic pain in early pregnancy is ectopic pregnancy. Ectopic pregnancy is when the pregnancy develops outside the uterine cavity. This is most common in the Fallopian tubes but can happen in other locations like the cervix, ovary and abdomen, There is a risk of rupture and bleeding which can be life threatening.
In ectopic pregnancy ultrasound most commonly identifies a mass or cyst next to the ovary. Less commonly, a live pregnancy is seen outside the uterus. There can be free fluid in the pelvis. This needs to be diagnosed early as there is a risk of rupture and life threatening bleeding. Treatment can be with medical and surgical approaches.
A normal pregnancy can also result in pelvic pain. This occurs when the uterus expands and the tissues stretch to accommodate the enlarging uterus. In these cases, the ultrasound will be normal showing a viable pregnancy. This is often a diagnosis of exclusion. Meaning that other more serious conditions need to be ruled out before saying pelvic pain in pregnancy is from ligament pain or related to normal pregnancy.
Many conditions unrelated to pregnancy can cause pelvic pain. Ovarian torsion needs to be recognized. This occurs when the ovary twists on itself. The blood supply becomes interrupted which can lead to tissue death of the ovary. Ultrasound will often show a swollen ovary with reduced or absent blood flow. There is often tenderness to pressure applied with the ultrasound probe. There is commonly fluid in the pelvis.
Ovarian cysts And fibroid tumors of the uterus can also cause pelvic pain. These can be well evaluated with ultrasound. Chronic pelvic inflammatory disease from infections can cause pelvic pain. Sometimes an abscess or collection of pus can be identified involving the ovary.
Bladder infections can be excluded with analysis of the urine. An appendix that extends low into the pelvis can also cause pelvic pain. Ultrasound can sometimes diagnose this condition. In cases where the appendix is not seen on ultrasound, an MRI can be done. We try to avoid CT to not expose the fetus to radiation. Other inflammatory conditions of the pelvic muscles, bones or joints can result in pain.
Ultrasound for pelvic pain in early pregnancy is commonly done to confirm that the pregnancy is viable and in the uterine cavity. The most important condition to exclude being an ectopic pregnancy. Ultrasound can also diagnose a wide range of conditions not related to pregnancy that can be responsible for pelvic pain in early pregnancy.