Rheumatoid Arthritis (RA): This is a common autoimmune disorder that can cause joint swelling and elevated sedimentation rate (SED rate). Pregnancy can sometimes improve RA symptoms, but it can also trigger or worsen them in some cases.

Systemic Lupus Erythematosus (SLE): An autoimmune disease that can cause joint pain, swelling, and elevated SED rate. Pregnancy can be a high-risk period for SLE flares.
Osteoarthritis: Although less likely to cause a significantly elevated SED rate, osteoarthritis can cause joint swelling and is common in pregnant women due to weight gain and joint stress.
Pregnancy-associated Osteoporosis: Rare, but can cause joint pain and swelling, especially in the hips and lower back.

Septic Arthritis: A serious infection within a joint that requires immediate medical attention. Symptoms can include sudden, severe joint pain, swelling, and fever.
Pre-eclampsia: A pregnancy complication characterized by high blood pressure and often accompanied by protein in the urine. It can cause systemic inflammation, potentially elevating the SED rate.
Deep Vein Thrombosis (DVT): Blood clots in the deep veins, which can cause swelling and pain in the affected limb. Pregnancy increases the risk of DVT.

Relapsing Polychondritis: A rare autoimmune disorder that can cause joint pain and swelling, among other symptoms.
Psoriatic Arthritis: An autoimmune condition that can cause joint pain, swelling, and skin psoriasis. It's less common than RA but should be considered, especially if there's a history of psoriasis.
Ankylosing Spondylitis: A form of arthritis that primarily affects the spine, although other joints can be involved. It's less common in women and may present with back pain and stiffness rather than swollen joints.