trying to get pregnant with irregular menstruation

Hi,
Welcome to ehealthforum,
There are many factors (ovarian, uterine, hormonal, stress etc) that affect chances of a successful pregnancy. You should consider getting a complete infertility work-up done for you and your partner to see if there are any underlying causes for the infertility/inability to conceive. Hormonal issues, problems involving ovaries and ovulation, uterine problems, cervical or vaginal infections should be ruled out for you (especially to look for cause of irregular periods which are suggestive of lack of periodic egg release from ovary/ovulation). For your partner, semen analysis should be done to rule out infections and to look at the quality and quantity of sperms produced. Have diet with foods rich in zinc content to ensure better maturation of egg and sperms. Monitor the cervical mucus changes and the BBT (basal body temperature) charting to predict your ovulation and time your intercourse for having fruitful results. Keep lying still for sometime after intercourse (do not change positions after ejaculation has occurred). Put pillows under buttocks to minimize semen spill. Have intercourse in positions that allow for deeper penetration for high deposit of semen. Treatment as needed (based on examination and investigations results) would be started to help you get pregnant. Consider visiting your gynecologist/obstetrician for further evaluation and assistance and be in regular follow-up and monitoring.
Take care.