Evaluation of abdominal pain in pregnancy

Abdominal pain in pregnancy is common. Many adaptive or physiologic changes of pregnancy affect the presentation. Women tend to visit doctors often as they are concerned about the health of their fetus. Patients require a careful assessment in order to reduce anxiety and give reassurance. If the clinical picture is unclear, a specialist should be consulted.[1]Chamberlain G. ABC of antenatal care: abdominal pain in pregnancy. BMJ. 1991 Jun 8;302(6789):1390-4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1670063 http://www.ncbi.nlm.nih.gov/pubmed/2059722?tool=bestpractice.com [2]Augustin G, Majerovic M. Non-obstetrical acute abdomen during pregnancy. Eur J Obstet Gynecol Rep Biol. 2007 Mar;131(1):4-12. http://www.ncbi.nlm.nih.gov/pubmed/16982130?tool=bestpractice.com

Diagnostic challenges and pitfalls

The physiologic and anatomic changes of various organs during the course of pregnancy result in major diagnostic challenges for the clinician. Reproductive organs share the same visceral innervations as the lower ileum, sigmoid colon, and rectum. It is therefore often difficult to differentiate between pain of gynecologic and gastrointestinal origin. Pain may be due not only to pregnancy-specific causes or gynecologic conditions, but to many other diseases whose symptoms and signs may be altered significantly by the pregnant state. This is particularly true from the late second trimester onward.

Evaluation is based on 2 patients: the mother and the fetus. The potential adverse effects of anesthesia, drugs, and radiation on the fetus often complicate the traditional diagnostic approach. As a result, the presence of the fetus may lead to delayed intervention or invasive diagnostic tests. Furthermore, there is a general reluctance to operate unnecessarily on a gravid patient.

The acute abdomen in pregnancy remains a diagnostic dilemma. As pregnancy stretches the anterior abdominal wall, the resulting peritoneal signs are often different from what is expected in the nonpregnant patient owing to lack of contact with the underlying inflammation. In addition, the clinical picture may be distorted by the uterus obstructing the movement of the omentum to the area of inflammation.[3]Sivanesaratnam V. The acute abdomen and the obstetrician. Bailleres Best Pract Res Clin Obstet Gynaecol. 2000 Feb;14(1):89-102. http://www.ncbi.nlm.nih.gov/pubmed/10789262?tool=bestpractice.com Laboratory parameters can be nonspecific and are often altered due to physiologic changes in pregnancy.

Despite advances in medical technology, preoperative diagnosis of acute abdominal conditions can still be inaccurate, increasing the rate of exploratory laparotomy, cesarean section, premature delivery, and perinatal death.

Physiologic causes of abdominal pain or discomfort in pregnancy

Include Braxton-Hicks contractions and round ligament pain.[4]Dhamecha R, Pajai S, Bhasin T. Acute abdomen in pregnancy: a comprehensive review of diagnosis and management. Cureus. 2023 Jun;15(6):e40679. https://pmc.ncbi.nlm.nih.gov/articles/PMC10357893 http://www.ncbi.nlm.nih.gov/pubmed/37485109?tool=bestpractice.com ​ Both may be uncomfortable, but they do not usually cause pain and do not intensify or cause cervical dilation.

Braxton-Hicks contractions are sporadic contractions of the uterine muscles that may occur in the second and third trimester. The round ligaments of the uterus increase in length and diameter as pregnancy progresses and can cause sharp pains in the abdomen and pelvis; symptoms resolve with rest.

It is important to carefully consider pathologic causes of abdominal pain before a physiologic cause is diagnosed in a pregnant patient presenting with abdominal pain.