A woman at 6 weeks gestation reports severe pain in her right shoulder. What should be suspected?

Severe pain in the right shoulder during early pregnancy, particularly at 6 weeks gestation, is most commonly associated with phrenic nerve irritation. The phrenic nerve is connected to the diaphragm, and irritation or referred pain to this nerve often manifests as shoulder pain. Since the diaphragm is innervated by the phrenic nerve which originates from the cervical spine, issues like ectopic pregnancy, which can occur around this time, may lead to referred pain due to irritation of the diaphragm.

While gallbladder issues could lead to right shoulder pain, they are more typically associated with a combination of abdominal pain and gastrointestinal symptoms rather than isolated shoulder pain. Appendicitis typically presents with abdominal pain, primarily in the lower right quadrant, and may not strongly manifest as shoulder pain. Pneumothorax could cause shoulder pain as well, but it would more likely present with respiratory distress and other thoracic symptoms rather than isolated shoulder discomfort.

Thus, in this context, the likelihood of the pain being linked to phrenic nerve irritation is a critical consideration in the management of the woman's condition.