I was thinking today about my friend who had the recent miscarriage and wondering how long her pregnancy test will stay positive for after the miscarriage.
As she is 40 this year, she wants to start trying for a baby again as soon as possible. Problem may be if she does not have a period before she conceives. This may cause two problems, dating the pregnancy as she will not know when she ovulated, and also knowing how to interpret a positive pregnancy test.
The pregnancy test can stay positive for some time after the miscarriage due to hcg levels still being elevated in the body. As pregnancy tests these days are more sensitive than they used to be, they can detect even lower hcg levels after miscarriage.
Many hospitals advise to do a home pregnancy test about 2 weeks after the miscarriage. If the home pregnancy test is negative then it means the hcg levels have dropped and so a positve test after a negative one should mean a pregnancy as long as the same sensitivity of pregnancy test is used at the same time of day (1st morning void).
I was not able to find an absolute answer on this. It depends on the levels of hcg at the time of the miscarraige and this varies enormously. General advice seems to be to give it at least 2 weeks after the miscarriage for the home pregnancy test to become negative. By then most home pregnancy tests will be negative.
Just a thought-if you get pregnant again before you have a period you could use a Clearblue Digital with Conception Indicator to date the pregnancy. If you do get pregnant before you have a period do not worry-the dating scans at the hospital are now very good