what causes pregnancy test to be positive and then negative a week after
There are few possibilities,
1: the kit is damaged,
2: you may have missed abortion,
3: you may have ectopic pregnancy which resolved on its own,
4: sometimes molar pregnancy with excessive high serum beta HCG.
Suggested:
1: serum b HCG
2: ultrasonography of pelvis
Same happened with me… 1st day 2 lines on strip in excitement i did 2nd time test again it was 2 lines . But when i went for blood test it comes negative. Then in strip test also single line