In the nineteenth century, physicians developed new ways to detect pregnancy, as they sought visible and palpable pregnancy signs that allowed a physician to make a diagnosis independent of a woman’s testimony about her symptoms. In the twentieth century demand for pregnancy diagnosis increased as more women sought formal prenatal care and took on new responsibilities for self-care during pregnancy. The first pregnancy lab test was introduced in 1927 and improved over the decades, and a home pregnancy test reached the American market in 1978. Since then, the tests, which measure human chorionic gonadotrophin (hCG) in maternal urine, have become a ubiquitous part of planned pregnancies, and have gotten increasingly sensitive. This means that women increasingly use them to detect very early pregnancies, many of which are not viable.