How do you spot pregnant individuals in the archaeological record? With great difficulty, it turns out. But that could be about to change, as a test capable of identifying hormones in skeletons breaks new ground in our understanding of ancient pregnancy.

For the first time, estrogen, progesterone, and testosterone have been detected in multiple human hard tissues, which could serve as an indicator of pregnancy, explain the authors of a recent study presenting the findings.

Nowadays, pregnancy tests work by identifying the hormone human chorionic gonadotrophin (hCG) in urine – at one time, this involved frogs, believe it or not. However, hCG doesn’t linger in the body for long enough to be detectable in ancient remains. This means that archaeologists have, until now, had to rely on discovering fetal remains in the abdomens of pregnant people, which is incredibly difficult, nigh on impossible, to do.

“New methods that can accurately identify pregnancy from skeletal remains are needed if we are to accurately reconstruct past women's reproductive histories, interpret their experiences within social and cultural contexts, and make effective comparisons between modern and archaeological populations,” the team behind the latest breakthrough explains.