Ovulation test paper weak positive to strong positive usually takes 2-3 days. Ovulation test paper is used to monitor the use of ovulation, ovulation test paper does not have to ovulation when only a line, about to ovulation when the performance of a dark and light two lines, to the time of ovulation will be the same color of the two lines, at this time known as strong positive. In the 24 hours before and after ovulation, as the luteinizing hormone in the body reaches its peak, the ovulation test paper can be used to detect a strong positive reaction. According to the follicular development, ovulation test paper from weak positive to strong positive usually takes 2-3 days, should be analyzed on a case-by-case basis, can not be generalized. Ovulation test paper to monitor ovulation is a method, not necessarily accurate, affected by a variety of factors, it is best to measure the basal body temperature at the same time, basal body temperature increases, it means that the ovulation period, but also ultrasound to monitor the follicles. It is recommended that women who are preparing for pregnancy can monitor ovulation with ovulation test strips according to their menstrual cycle under the guidance of their doctor, and guide coitus to increase the chances of conception. Keep your mood happy, stress should not be too much, work and rest, diet is more regular, 3 months before pregnancy to start oral folic acid.