Patterns of fertility at later ages of reproduction

Abstract

This paper discusses some of the things that demographers know about fertility at later ages of reproduction in developed countries. The nature of the information available through, for example, vital statistics is often a product of history and of administrative requirements, rather than the result of a well-based scheme. Surveys are frequently used to fill the gaps in major sources, but no survey appears to have been carried out specifically on the topic under discussion here. The available information will be discussed under four broad headings: (1) the levels and the trends of late fertility, as compared with fertility at younger ages; (2) the specific characteristics of mothers giving birth at later ages; (3) the specific characteristics of the corresponding births, and the risks for pregnancies at older ages; (4) the question of whether these births are less wanted than others.

The Aging and Aged Ovary

“…123 Ovulation frequency and pregnancy rates are reduced undeniably as the human female ages, but an individual 45 years old still may be regularly ovulatory. 124 Ovulation may have occurred as late as the final menses in three of eight women, but no evidence of ovulation after menopause existed. 79 In the immediate postmenopausal period, 20% to 40% of women studied had estrogen levels consistent with follicular development, 125,126 although by 2 to 3 years after menopause, estrogen levels generally fall into the castrate range.…”