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.
Normally a blood test or obstetric examination helps to determine a true pregnancy from a false one. Theoretically, a man being injected with HCG could have a positive pregnancy test, even though one would know the man was not pregnant. Other medications may also cause a false positive on a pregnancy test. These include anti-convulsants, medications to treat Parkinsonâs disease, certain tranquilizers, and certain diuretics.