Hello, and I hope I can help you today. First of all, I want to reassure you that no matter what your endometrial measurement may be, 80% of couples will conceive within one year naturally. Couples are not diagnosed as infertile until you have been trying and been unable to become pregnant for over one year. Endometrial thickness is really only relevant in the context of couples trying to get pregnant through in vitro fertilization. The thickness of your uterine lining is somewhat related to your estrogen levels. When couples are undergoing IVF, treating with additional estrogen can thicken the uterine lining. However, because you ve been only trying to get pregnant for four months, your endometrial lining may have absolutely nothing to do with the reason why you have not yet conceived. Furthermore, unless your husband s sperm count has been shown to be decreased, Mesalazine should not have any effect on fertility nor should affect any health of a developing baby should you conceive. Medications taken during pregnancy by the mother can affect the fetus, but not any medication taken by the father, because medication cannot be transmitted before fertilization through sperm. So unless the medication causes the sperm count to be low or abnormal, there is no medical reason why your husband needs to be off his medication for colitis in order for you and need to conceive successfully. I suggest that if he needs the medication for his health that he continue to take it. As for is maximizing your chance of healthy pregnancy, the best thing you can do is get plenty of sleep, eat a well-balanced diet, take prenatal vitamins, and tried to have regular(at least 2 to 3 days a week) unprotected intercourse from the time your menstrual period finishes until you begin to feel premenstrual symptoms. I hope that I was able to adequately answer your question today, and I wish you and your husband the best of luck in conceiving. Best wishes, Dr. Brown