Any cause for an acute abdomen can occur coincident with pregnancy, while others are specific to pregnancy.

History

1. ▪ Time of onset, duration, intensity and character of abdominal pain during pregnancy and associated symptoms need to be established.

2. ▪ Evaluation of gestational age is essential as aetiologies change with gestational age, and fetal viability also depends on this.

Examination

1. ▪ Peritoneal signs are often absent in pregnancy due to lifting and stretching of the anterior abdominal wall. Underlying inflammation has no direct contact with the parietal peritoneum, which precludes any expected muscular response such as guarding.

2. ▪ The uterus can obstruct and inhibit movement of the omentum to an area of inflammation, distorting the clinical picture.

3. ▪ Examination of patient in the right or left decubitus position may help distinguish extra-uterine tenderness from uterine tenderness.

4. ▪ Due to the gravid abdomen, the location of intra-abdominal contents will vary at different gestations.

Investigations

1. ▪ Blood tests are dependent on the suspected pathology. Some laboratory tests have altered reference ranges in pregnancy. For example, pregnancy can produce white blood cell counts of 6000–16000/mm3 in the second and third trimesters and 20000–30000/mm3 in early labour.

2. ▪ Ultrasound is the most frequently used non-invasive investigation for evaluating the pregnant abdomen.

Differential diagnoses related to pregnancy

Early pregnancy complications such as ectopic pregnancy or miscarriage. Consider rare possibility of a heterotopic pregnancy (1:7000–1:30000).