If you are late on one menstrual cycle and miss the next is it possible pregnancy test will be negative until missed period?

Yes, it is possible for a pregnancy test to be negative even if you have missed two menstrual cycles. This can happen for a number of reasons:

* Implantation bleeding: Some women experience implantation bleeding, which is light bleeding that occurs when the fertilized egg implants in the uterine wall. This can happen a few days before the expected menstrual period, and can be mistaken for a period.

* Low levels of hCG: The hormone human chorionic gonadotropin (hCG) is produced by the placenta after implantation. The level of hCG rises as the pregnancy progresses, and is what pregnancy tests detect. However, it can take a few days or even weeks for hCG levels to rise to the point where they are detectable by a pregnancy test.

* Medications: Some medications, such as birth control pills, can interfere with ovulation and cause irregular menstrual cycles. This can make it difficult to know when you are actually ovulating, and you may miss your period as a result.

* Other medical conditions: Some medical conditions, such as polycystic ovary syndrome (PCOS), can also cause irregular menstrual cycles. If you have PCOS, you may not ovulate every month, which can make it difficult to conceive.

If you are concerned that you may be pregnant, it is important to see a doctor. A blood test can be done to measure your hCG levels and confirm pregnancy.