In the late 1920s, the German gynaecologists Selmar Aschheim and Bernhard Zondek discovered a reaction that could reliably test for early pregnancy with around 98% accuracy. This happened in a period known to endocrine historians as the “gold rush era of hormones”, a time of intense discovery where physicians across the world entered a quasi-race to identify the different hormones of the body.
You have Aschheim and Zonek to thank for the possibility of peace of mind…or the prospect of looking for a Kita near you.
Aschheim, a born-and-bred Berliner, and Zondek, from what is now Wronki, Poland (then part of Germany), teamed up in 1919 at the encouragement of the Women’s Clinic of the Charité, where both worked at the time. They were an unlikely pairing for a major scientific discovery; Ascheim was the head of his own lab, and Zondek was freshly graduated.
On January 22 1926, they revealed one of their first major discoveries in lectures to the Berlin Society of Obstetrics and Gynaecology. Results from their experiments suggested that a gland in the brain made hormones that affected the ovaries and reproductive system.
After injecting so-called grafts, pieces of living tissue, of various glands in the body into sexually immature female mice, the pair observed that it was only the brain’s anterior pituitary gland that stimulated changes in the ovaries of the mice. With these findings as a base, they hypothesised that the same hormones found in the anterior pituitary gland might be found in the urine of pregnant people – so they set out to prove it.
Aschheim and Zondek developed a test whereby sexually immature mice were injected with human urine (ideally the first urine of the day, as it is the most concentrated) over the course of three days. On the fifth day, the mice would be killed, dissected and their organs examined.
What they discovered was that if the urine of a pregnant person was used, the reproductive organs of the mice were prematurely “sexually mature”, and in tests with urine from non-pregnant people, there was no change to the reproductive organs of the mice. The scientists concluded that the same hormones present in the anterior pituitary gland can be found in a pregnant person’s urine, as both the anterior pituitary graft and pregnant people’s urine stimulated the same changes in the ovaries of mice.
Importantly, the test allowed for early detection of pregnancy. Anyone suspicious they might be pregnant could test their urine as early as five days after their missed period – all you needed was to sacrifice a few mice. Aschheim and Zondek published their results in 1928 in Klinische Wochenschrift with further mentions in a variety of other journals, including the prestigious The Lancet in 1930.
The latter journal even noted how easy the Aschheim-Zondek test would be for physicians: “The family doctor will be grateful for the simplicity of his share, which consists only in collecting morning urine from the patient and possibly adding a drop of tricresol as a preservative.”
In the following decade, the method underwent several alterations. The Friedman test introduced a popular change in 1931, when immature female mice were swapped for adult female rabbits. The rabbits were easier to manage and the test could be completed in under two days. However, the sacrifice of the rabbits, as with the mice, was unfortunately still par for the course.
These animal-based tests remained the norm until 1960 with the introduction of the antibody tests.
In 1934, the African clawed toad was suggested as a replacement for the rabbit as the test could be done in a swift 18 hours and the toad left with its life (an egg would be laid as proof of pregnancy). These animal-based tests remained the norm until 1960 with the introduction of the antibody tests we use today.
Like with many great contributors to German society at that time, it was not long after their discovery that both Aschheim and Zondek were forced to flee the country. As Jewish physicians living under Nazi rule, the antisemitic laws forced them out of their positions as professor and chief doctor. Aschheim fled to France, where he remained until his death in 1965.
Zondek attempted to settle in Sweden in 1933; however, he was met with similar hostility to that which he fled, with more than 1,000 Swedish doctors protesting his application to practise medicine there. Zondek moved to Palestine, where he ran the hormone laboratory at the Hadassah Hospital in Jerusalem, and eventually relocated to New York to continue his research until his death in 1966.
The knowledge gained from the Aschheim-Zondek test laid the foundation for home pregnancy tests as we know them today. What scientists in the 1920s thought of as a string of hormones released during pregnancy from the anterior pituitary is now known to be the singular hormone human chorionic gonadotropin (hCG), which instructs the body to prepare for a foetus.
Modern antibody pregnancy tests are designed to detect hCG in the same way that matured ovaries would register as a ‘positive detection’ of the hormone in the Aschheim-Zondek test. So next time you’re sneaking through the pregnancy test aisle at Rossmann, remember that you have Aschheim and Zonek to thank for the possibility of peace of mind, preparedness or the prospect of looking for a Kita near you.
