A midwife is called a midwife not because the midwife is in the middle of anything, nor because during the birth of children the
midwife is helping the wife as opposed to the husband. It is pretty uncommon to find men who are midwives but I guess they do exist.
The etymology of the word midwife reflects the fact that assisting in bringing a new little person into this world has long been a gender role and almost completely dominated by women.
The wife part of midwife has nothing to do with the marital state of the parents of the baby being delivered, nor that of the midwife herself. The word wife predates an association with being married or unmarried and in our earliest records just meant "woman". If we paste that meaning on midwife we get midwoman. Unfortunately this doesn’t get us much further along the way toward understanding why these deliverers of babies might be called midwives. We have to take another step and examine the mid part of midwife. In this case mid does not mean middle.
There don’t seem to be too many examples of words other than midwife that retain an old meaning of mid but what it is believed to have mean was "with". Thus midwife literally means "with woman" and refers to the fact that this woman called a midwife has the job of being with the mother during her labor and delivery.
Слова на английском, связанные с беременностью и родами
midwife – повивальная бабка; акушерка; повитуха
nurse-midwife – медсестра, имеющая сертификат акушерки
pregnancy – беременность
pregnancy test – тест на беременность
childbirth, delivery, (разг.) confinement – роды
labor [birth, dilating] pains / parodynia – родовые схватки
assist in childbirth – принимать роды
woman in childbirth / woman recently confined – (рожающая) роженица / (родившая) роженица
infant / babe in arms – грудной младенец