This interesting article suggests that the reproductive system of horses has changed little over the course of millions of years. ~ HfH
The fossil was discovered in Germany in 2000, but the scientific analysis was only now completed and published in the open-access journal PLOS One.
The animal was an early relative of the modern horse – known as Eurohippus messelensis – and would have been about the size of a small dog.
The foetus is about 12.5 centimetres long and is mostly intact, except for a crushed skull.