de Quervain's disease of pregnancy and lactation is usually self-limited and responds well to nonsurgical treatment. We conducted a randomized prospective study on 19 wrists of 18 patients with de Quervain's disease who were either pregnant or breast-feeding. One group had a cortisone injection into the tendon sheath and the other group used thumb spica splints. All 9 patients with injections had complete pain relief with only one late recurrence. None of the patients with splints had complete pain relief; however, at the end of the lactation period, 8 had spontaneous resolution of symptoms and 1 received a cortisone injection. de Quervain's disease of pregnancy and lactation is self-limited and can be treated successfully with cortisone injection. Splinting does not provide satisfactory pain relief.