One of the most important reasons to diagnose early is that the longer you delay the more likely you may have complications, particularly the perforation of the appendix. If this happens, the fetal loss rates and the preterm labor rates are increased, upwards of 36%. This is more likely in the third trimester. Though the risk to mothers has dropped to near zero with good surgical technique as well as antibiotics.
Lower right quadrant pain is the most common symptom, but 70% of pregnant women will not have a fever. So you will most likely have an ultrasound if your practitioners suspect an appendicitis. This is very good for determining what is wrong in the first and second trimesters, 86% as it is when you are not pregnant. The third trimester may be more difficult and your practitioner may suggest a CT scan.
If you are in the first or second trimester, you will most likely be able to have a laparoscopy for your surgery. In the third trimester, you will have a larger incision due to an open incision. During surgery, after the 24 week mark, fetal monitoring should be used. About 80% of women will have preterm contractions, though the vast majority will not have preterm labor. Only between 5-14% of women will have their babies born early after an appendectomy.
Obstetrics: Normal and Problem Pregnancies. Gabbe, S, Niebyl, J, Simpson, JL. Fifth Edition.