An ovulation test measures the concentration of the ovulation hormone (luteinizing hormone). This means that when the test is positive, the woman will ovulate within the next24-36 hours.

But the LH hormones are so similar to the pregnancy hormone hCG that an ovulation test may well be positive if you are pregnant. This can happen because the test cannot separate the LH hormone from the hCG hormone. Therefore, a positive ovulation test may well be a sign of pregnancy.

The right time to test for ovulation

Use the chart below if you want to see when, based on your cycle length, you are expected to ovulate or when you should start testing if you want to use an ovulation test. To see when you ovulate, you can also use the temperature method, which you can read more about here: What is the temperature method BBT and how does it work? – Gravidtid

Cycle length

Expected ovulation on this number of days following last menstrual cycles first day

Start testing with ovulation tests as many days after the first day of your last period

21

7

5

22

8

6

23

9

7

24

10

8

25

11

9

26

12

10

27

13

11

28

14

12

29

15

13

30

16

14

31

17

15

32

18

16

33

19

17

34

20

18

35

21

19

36

22

20

37

23

21

38

24

22

39

25

23

40

26

24

If you want to use ovulation tests, you can see our large selection here: Ægløsningstests – Gravidtid And if you want to follow the temperature method, you can see our selection of thermometers here: Termometre – Gravidtid