It depends on what is considered groundbreaking. If I take it to mean doing something outside what we might consider "normal", I think of two women who travelled "across the world" on multiple-week sea voyages, whilst heavily pregnant, not knowing what was awaiting them when they got there. One in particular who comes to mind is my great-great-great-grand aunt, who made the journey across the ocean from England to the Colony of New South Wales in the early 1830s with her then husband and their five children. Isabella didn't make it all the way to Sydney town before the baby decided his time to join the world was while the ship was still mid-Indian Ocean. I'm not sure if there was regular stop for resupply, or re-watering, or some other reason, or if they just happened to stop at one of the islands out there, but junior made his appearance on that island, completing the journey most likely squalling most of the way. Isabella went on to have two more children (to that husband) in the colony. She also had another three children to her second husband, but did not survive the birth of her last child, a son, dying just ten days after he was born in what is now Tasmania. In her time in Sydney Isabella and her mother (also involving her father, and her brothers) held musical evenings, entertaining even the "highest" in the colony, right up to the Governor and Lt Governor, taught music, ran a boarding house, and so on.
The other who comes to mind travelled from Scotland to the Colony of New South Wales in the late 1860s, starting the journey a short time after losing her husband to a drowning incident in a Scottish lake. We don't know if the husband was originally meant to travel as well, but Margaret packed up her six children, whatever goods she could bring, and her pregnant belly, and set off. A short while after arriving (a couple of months) her last daughter (of marriage one) arrived, the first Australian-born of that line. Three years later Margaret was married again, having three more children before that husband also died leaving her a widow for the second time. Nothing daunted, she went on the marry for a third time two years later.
While maybe not startlingly groundbreaking in the way of someone making scientific discoveries, or inventing someone, they did step out of their ordinary lives and do something most of us wouldn't consider. (I mean, it's a drag packing up and moving at any time, but while pregnant and NO AIR or train TRAVEL. Not even a steam ship. SAILING ships, seasickness, storms, children under the age of ten cooped up on a vessel not much larger than half my house .. did I mention children under ten years of age? Illness, death, squabbling .. and not just the children.)