If the partners are planning to conceive a child, the best time for intercourse is 4 days before the expected peak of ovulation and 1 day after the peak of the ovulation phase. Some sources talk about 4 days before and 4 days after, while it is advisable to have intercourse more often, e.g. every 2 days. However, the regularity of unprotected intercourse may not increase the chance of fertilization if the intercourse is poorly timed and ovulation has already taken place or is still a long time before it.