The earliest symptom of early pregnancy is menorrhagia. If you have intercourse after 3 days of menstruation and want to know if you are pregnant, you should also have a blood HCG or urine test paper test more than 1 week after your menstruation. If the blood HCG value exceeds the normal range or the test paper is positive, it indicates a high possibility of early pregnancy. Women who have a menstrual cycle of 28-30 days at 3 days clean with normal periods are unlikely to ovulate and have a relatively low chance of conception. If there is a plan to conceive, it is best to actively prepare for pregnancy and monitor ovulation to help guide conception. If there is no intention to conceive, do not use the safe period method of contraception. Ovulation is affected by a variety of factors and may be early or delayed, and there is a possibility of conception during the safe period. Also women with irregular menstrual periods ovulate irregularly and must take effective contraceptive measures to avoid the damage to the body caused by an unplanned pregnancy to have an abortion.