Twin: One of two children produced in the same pregnancy. Twins can develop from one ovum (egg) or from two ova (eggs). Twins who develop from a single ovum are called monozygotic or identical twins. They have identical genomes. Twins who develop from two ova that are fertilized at the same time are called dizygotic or fraternal twins. They are nonidentical and have different genomes.
Unfortunately, many women have a small amount of this hormone continuously and if the level gets high enough just before a period, you could get a false pregnancy test result. The best time to use a urine test for pregnancy is three to five days after your missed period.
A false negative result is when the test says you are not pregnant but you are. This can be misleading and when using home pregnancy tests you must be very careful of avoiding any factors that may cause false results. The major reason for a false negative test is that you took the test too early.