A miscarriage sometimes happens because there is a weakness of the cervix, called an incompetent cervix, which cannot hold the pregnancy. A miscarriage from an incompetent cervix usually occurs in the second trimester. There are usually few symptoms before a miscarriage caused by cervical insufficiency.
Police perjury (or testilying in United States police  slang) is the act of a police officer giving false testimony. It is typically used in a criminal trial to make the case against a defendant who the police believe to be guilty when irregularities during the suspect's arrest or search threaten to result in acquittal.
Both individual states and the federal government have laws making perjury a criminal offense. While the basic definition of perjury is the same at both the federal and the state level, the penalties may be different. For instance, the federal law against perjury in the U.S. Code classifies perjury as a felony.