How do you titrate lithium for patients with bipolar affective disorder during pregnancy and immediately after delivery in the context of fluid shifts and changing levels?

Great question!

Lithium clearance increases during pregnancy, and some women may require a dose increase to maintain therapeutic benefits. It is not my practice to prophylactically increase the dose during pregnancy, but I do recommend monitoring labs (lithium level, BUN and creatinine, and TSH) each trimester and postpartum. I typically adjust the dose based on changes in level and symptom burden.

At the time of delivery, rapid shifts of fluids may affect the blood concentration of lithium, and thus close monitoring is warranted to determine whether dose adjustments are needed. Some recommend discontinuing lithium altogether at the onset of labor to minimize side effects and complications with the neonate. Others have proposed maintaining...

I agree with the above. Usually, at therapeutic doses, patients will have a slight tremor. When patients are destabilized and entering a cycle the tremor disappears due to lithium being transported to the intracellular space and there is a drop in level. Some old-school mood disorder specialists “titrate to tremor”. I find this to be quite useful for patients who are in high-stress and demanding careers or travel and have jet lag etc. and educate them to go up on dose by 150-300 mg for 4-5 days then go back to regular dose. Might be a good tool for pregnancy? I agree with monitoring levels and labs every trimester.