I am 42 years old. three years ago, i used chlomid for three cycles but didn't conceive only to conceive in the forth cycle after stopping it. could i be chlomid resistant? are there chances that it can work for me now given my age?

Although at "42", pregnancy is statistically low, Clomiphene is an ovulation induction agent and may work at higher doses. Suggest an appointment with a reproductive endocrinologist who may use other methods for ovulation induction, but first get a semen analysis for your partner, and ask your GYN physician to check tubal patency by a hysterosalpingogram (a test to make sure the tubes are open.