's ''The Doctor's Visit''. Included in this 17th-century painting is a depiction of a dubious pregnancy test: a ribbon dipped in the patient's urine and then burned. Records of attempts at pregnancy testing have been found as far back as the
ancient Greek and
ancient Egyptian cultures. The ancient Egyptians watered bags of
wheat and
barley with the urine of a possibly pregnant woman. Germination indicated pregnancy. The type of grain that sprouted was taken as an indicator of the fetus's sex.
Hippocrates suggested that a woman who had missed her period should drink a solution of
honey in water at bedtime: resulting abdominal distention and cramps would indicate the presence of a pregnancy.
Avicenna and many physicians after him in the
Middle Ages performed
uroscopy, a nonscientific method to evaluate urine.
Selmar Aschheim and
Bernhard Zondek introduced testing based on the presence of
human chorionic gonadotropin (hCG) in 1928. Early studies of hCG had concluded that it was produced by the
pituitary gland. In the 1930s, Doctor
Georgeanna Jones discovered that hCG was produced not by the pituitary gland, but by the
placenta. This discovery was important in relying on hCG as an early marker of pregnancy. In the Aschheim and Zondek test, an infantile female
mouse was injected subcutaneously with urine of the woman to be tested, and the mouse later was killed and dissected. Presence of
ovulation indicated that the urine contained hCG and meant that the subject was pregnant. A similar test was developed
using immature rabbits. At the beginning of the 1930s,
Hillel Shapiro and Harry Zwarenstein, who were researchers at the
University of Cape Town, discovered that if urine from a pregnant person was injected into the South African
Xenopus frog and the frog ovulated, this indicated that the subject was pregnant. This test, known as the
frog test, was used throughout the world from the 1930s to 1960s, with
Xenopus frogs being exported in great numbers. Shapiro's advisor,
Lancelot Hogben, claimed to have developed the pregnancy test himself, but this was refuted by both Shapiro and Zwarenstein in a letter to the
British Medical Journal. A later article, independently authored, granted Hogben credit for the principle of using
Xenopus to determine gonadotropin levels in a pregnant person's urine, but not for its usage as a functional pregnancy test. Hormonal pregnancy tests such as
Primodos and
Duogynon were used in the 1960s and 1970s in the UK and Germany. These tests involved taking a dosed amount of hormones, and observing the response a few days later. A pregnant person does not react, as they are producing the hormones in pregnancy; a subject who is not pregnant responds to the absence of the hormone by beginning a new menstrual cycle. While the test was (is) generally considered accurate, research advancements have replaced it with simpler techniques. Immunologic pregnancy tests were introduced in 1960 when Wide and
Gemzell presented a test based on in-vitro hemagglutination inhibition. This was a first step away from in-vivo pregnancy testing Direct measurement of
antigens, such as hCG, was made possible after the invention of the
radioimmunoassay in 1959. Radioimmunoassays require sophisticated apparatus and special radiation precautions and are expensive.
Organon International obtained the first patent on a home pregnancy test in 1969, two years after product designer
Margaret Crane noticed that the laboratory testing procedure was relatively simple and made a prototype. The product became available in Canada in 1971, and the United States in 1977, after delays caused by concerns over sexual morality and the ability of potentially pregnant women to perform the test and cope with the results without a doctor. Another home pregnancy testing kit was based on the work of
Judith Vaitukaitis and Glenn Braunstein, who developed a sensitive hCG assay at the
National Institutes of Health. That test went onto the market under the name e.p.t. in 1978. e.p.t. originally stood for "Early Pregnancy Test" but was later changed to "Error Proof Test". ==See also==