How should seat belts be properly used during pregnancy?

There is substantial evidence that seat belt use during pregnancy protects both the mother and fetus. The seat belt should be used with both the lap belt and shoulder harness. The lap belt should be placed under the abdomen, across the pubic bone and the shoulder harness should be between the breasts. There should not be excessive slack in either belt and both lap and shoulder restraints should be as snug as comfort will allow.