Upvote:1
Such a study would be quite local, requiring a detailed study of church records for baptisms, marriages and deaths.
I can provide some information from 19th century:
1802: Lucinda Pixley, age 19, married at age 19 to David Powers, in Vermont They had two daughters, in 1802 and 1808. The family moved to New York; the husband died in 1813, while serving in the US Army. They may have had some other difficulties as well, but documentation is sparse.
1817: Vinera Powers, age 15, married Samuel Stillman Glover, in upstate New York. They had 11 children, with one set of twins, between 1818 and 1847. Most of the gaps were 2 years or so, with one much longer gap of five years. The family moved to Michigan. The mother and new born twins died in 1847.
1860: Annette Glover, age 16, married Jesse Youngs in Michigan. They were married for 64 years. They had 17 children, of whom 9 lived to adulthood, between 1861 and 1898. There were several long gaps of 5 and 6 years. She was 54 when her final child was born; the final seven all died as infants, and were left out of the family bible record, but have birth and death certificates.
Annette Glover & Jesse Youngs, 50nd wedding anniversary. Image from our family archive. Ella (Youngs) Kelly and her husband, C.J. Kelly, are on the left.
1879: Ella Youngs, age 16, married Christian James Kelly in Michigan. They were married for 38 years, and had 11 children between 1880 and 1896. Eight of the children lived to adulthood, with three dying as young children.
1913: Eloise Kelly, age 17, married Harlan Foster in Michigan. They were married for seven years and had three children, all living to adulthood. Her husband was absent for two years while a member of the AEF serving in Europe, and they divorced shortly after his return.
These are five generations of the same family. The large families all lived on farms, under stable circumstances. The husbands were often much older than the wives. By 1900 the economic situation was changing, and only two of the children of this final generation had large families.
From general research on these and other families the typical spacing of children is every two years, with the first child born within a year of the marriage. Note that a nursing mother will ordinarily not conceive, so unless a wet nurse is being used, spacing of less than two years is uncommon in older times, though goats milk is a workable replacement.