I have irregular period, and my period on Saturday and ended on Tuesday. How fast can I become pregnant?

Getting pregnant depends on several factors, including the regularity of your menstrual cycle and the timing of intercourse. In general, getting pregnant when you have an irregular cycle can be more difficult than if you had a regular one because it's harder to predict ovulation.

That said, while having an irregular period may reduce your chances of becoming pregnant each month, it doesn't necessarily mean that pregnancy is out of reach—many couples with irregular cycles do get pregnant. The key is to understand how menstrual cycles work and what influences conception so that you can time intercourse correctly for maximized chances of conceiving.

First off, ovulation typically occurs about 14 days before your next expected period (in a regular 28 day cycle). During this window around ovulation, the cervical mucus becomes thinner and clearer which makes it easier for sperm to travel up from the vagina into the uterus to fertilize an egg. Thus this is usually referred to as a woman's "fertile window." This can occur any time during an irregular menstrual cycle; however since there isn't much predictability due to varying lengths between periods, tracking other signs such as body temperature or using an ovulation predictor kit are useful methods for determining when one might be most fertile in order to optimize attempts at natural conception.

In addition fertility treatments like intrauterine insemination (IUI) or in vitro fertilization (IVF) may also help those with irregular periods increase their chances at becoming pregnant by helping them better track their fertile window through hormone monitoring and/or artificial reproductive technology (ART). However these treatments require medical supervision so always speak with a health care professional if you are considering either route as they offer personalized advice tailored specifically towards your needs.

Overall while having an irregular period may make predicting fertility windows more challenging compared traditional 28-day cycles there's still hope for couples trying conceive naturally or via ART interventions; just remember knowledge really is power! With proper understanding and accurate tracking methods odds are increased tremendously making pregnancy attainable even with less than perfect conditions for conception!