Talk to Gynecologist on Gynaecologist

Married from 7 months. Menstrual cycle is irregular nd trying to conceive..Taking folic acid 5mg. - Last few months history (periods start at 28th day for 2 consecutive months then start at 35th day for next two consecutive months nd this time they started today at 38th day of my cycle.. This time I was also feeling a pin like pain in my lower abdomen sometimes in centre, right or left for like 15 days, gas and constipation too.. So I did a pregnancy test but negative.. Last time I bought an ovulation kit and did test at 11 14 16 19 nd 21 day and all were negative..so that try go in a vein.. My queries are: What would be my ovulation days to try ? What should i do for conception? how to make my cycle regular ?