Ttc. Been using ovulation tests for 4-5 months, seeing LH spikes. Not pregnant yet. When should I consult a doctor?

Usually at 1 year. For a woman under age 35 who is trying to conceive most recommend she be checked out if no pregnancy after one year of trying. This is because by a year of trying 80% of women are pregnant. I recommend a woman see someone sooner if there is an obvious problem such as periods being irregular, since often irregular periods - lack of periods or very close periods - can indicate ovulation problems.