26-year-old pregnant woman,
decreased fetal movement...
Start with a trans-abdominal ultrasound scan. If the patient’s gestational age is greater than 6-8 weeks by dates, you should be able to visualize changes suggestive of an intrauterine pregnancy. Obtain both transverse and sagittal views of the uterus and pelvis. If you do not see an IUP at this stage, scan through the abdomen and pelvis and assess for free fluid. A small amount of physiological free fluid can be normal, but in the absence of a double-decidual sign around a gestational sac, this free fluid may mean your pregnant patient has an ectopic pregnancy.