These are usually known by the term "Jury of Matrons", searches on that will be more productive.

A Jury of Matrons, empaneled by writ or simply by a judge commandeering random women, was an inquiry into the very private business of "is this woman pregnant or not", rather than a body that would determine guilt or innocence. Specifically, they were called on to determine whether a pregnancy had reached "the quickening", an indeterminate point somewhere between the third and sixth month, when the fetus was said to have "moved in the womb"-- itself an interesting window onto earlier ideas of stages of pregnancy.

We first hear of a Jury of Matrons being convened by a writ de ventre inspiciendo - literally "to inspect the belly"; it remains of some contemporary jurisprudential interest as a precedent for practices to compel medical examination of a defendant (or indeed in some instances, of a plaintiff). This writ didn't begin as a criminal law inquiry-- the early references date to Bracton (12th and 13th centuries), and where we see it there are in the cases where a man dies childless, but his widow claims she is pregnant-- in that case the inspection would be to determine whether there is an as yet unborn heir to the inheritance.

As an illustration of this in criminal practice, consider this complaint in the British Medical Journal in 1878

WHEN shall we hear the last of this ancient method of determining the question of pregnancy for legal purposes? In the recent trial at Chester, the woman Heeson, who was proved to have destroyed by poison her mother and two of her children, pleaded pregnancy in bar of execution. Thereupon, according to the provision of the criminal law, a jury of women was taken from among those casually present in court (de circurnstantibus); and they were sworn to try not only whether the convict was pregnant, but whether she was quick with child or not. The learned judge who tried the case very properly directed that the surgeon of the gaol, Dr. McEwen, should be associated with the twelve matrons or discreet women required by the law, He was sworn to assist the jury; and, after due consultation, they returned a verdict that the woman was with child of a quick nature; whereupon, although judgment was passed upon her, her execution was suspended until she had been delivered, and until a reasonable time after that event, or until such a time after that it is proved by the course of nature she could not have been with child . . .

Legal as well as medical opinion had turned against this form, and the 1878 date of this article isn't coincidental, the practice largely ended with law reform in 1879. This was both a matter of policy and concomitant to the declining use of capital punishment. At this late date, physicians were actually doing the examination; at earlier dates the women themselves or midwives do the examining, and you sometimes have cases of dispute between medical professionals and the Jury. When I say "largely ended" -- there are cases into the first half of the 20th century, the last recorded date is 1931.

The Jury of Matrons was one of the last examples of an earlier common law practice, the use of specialized juries where expertise was needed. So, we are told of the empanelling of a jury of "cooks and fishmongers" to evaluate charges of bad food in 14th century London. One can also look to the example of the jury de medietas linguae (literally a "half tongued jury"), a jury used when the defendant was a foreigner, composed one half of people of his nation, speaking his language; the other half of Englishmen. There were also considerations of status rather than expertise-- trials for "peers of the realm" were conducted in the House of Lords until 1948; that's not a presumption of some special knowledge, just in effect a "jury of peer's peers".

Today, specialist inquiry proceeds with expert witnesses or special masters-- specialized juries can be seen as an alternative. For a long time there was little scholarly attention to this topic-- the decades old references below aren't being needlessly antiquarian. More recently these juries have interested two sorts of scholars-- feminist historians interested in the particulars, and contemporary legal scholars looking to the past for examples of how to deal with material that may be too complex for a jury of laypeople.

Sources:

“The Case for Special Juries in Complex Civil Litigation.” The Yale Law Journal, vol. 89, no. 6, 1980, pp. 1155–1176.

Thayer, James B. “The Jury and Its Development. II.” Harvard Law Review, vol. 5, no. 7, 1892, pp. 295–319. [Despite being more than a century old, this paper is cited very frequently, would be helpful if someone would revisit Thayer's sources]

Hollond, H. A. “New Light on Writs and Bills, and on the Influence of Roman Law in England in the Twelfth and Thirteenth Centuries.” The Cambridge Law Journal, vol. 8, no. 3, 1944, pp. 252–264.

Not a lot gets written on this subject, but there have been a few recent articles, hot off the presses is:

Kevin Crosby, Abolishing Juries of Matrons, Oxford Journal of Legal Studies, Volume 39, Issue 2, Summer 2019, Pages 259–284, https://doi.org/10.1093/ojls/gqy037

*Moore