@article{0094f00abc48434e9507d15c4240072c,
title = "Components of age-specific fecundability",
abstract = "Fecundability - the monthly probability of conception - incorporates both physiological and behavioural elements that vary across a woman{\textquoteright}s reproductive life span. How much of the variation in fecundability during the reproductive period can be attributed to age-related changes in physiology, and how much to variation in coital frequency? We use a mathematical model of fecundability to consider this question. Intra-uterine mortality has an important effect on fecundability: effective fecundability (the likelihood of a conception that results in a live birth) is less than half of total fecundability (the likelihood of any conception) at nearly all ages when coital frequency is held constant. The change in effective fecundability with increasing coital frequency is non-linear: it declines with increasing frequency. At all coital frequencies, the effects of increasing physiological age are greatest at the youngest and oldest reproductive ages, while between the ages of 20 and 30 physiological change has only a small impact on effective fecundability.",
author = "Maxine Weinstein and Wood, {James W.} and Stoto, {Michael A.} and Greenfield, {Daniel D.}",
note = "Funding Information: It is now well established that effective fecundability varies in a systematic fashion with the age of the female partner, rising rapidly to a peak during her early 20s and then declining slowly to zero at about the time of menopause? However, there is a remarkable lack of agreement about the cause of these changes, in particular whether they are attributable primarily to changes in coital frequency, or to changes in the * Exploratory analyses underlying part of this work were presented at the Seminar on Biomedical and Demographic Determinants of Human Reproduction, Baltimore, Maryland, January 1988. We thank Sharon Heinle, Monique van Stiphout and Lyle Piper for their assistance in preparing the manuscript. This research was supported by NICHD grant RO1-HD-20989. t Department of Demography, Georgetown University. :~ Department of Anthropology, and Population Issues Research Center, The Pennsylvania State University. § Institute of Medicine, National Academy of Sciences. 1 A recent hazard analysis, however, suggests that fecundability and the waiting time to conception are unaffected to a remarkable degree by a wide variety of sperm characteristics including total count and motility, reinforcing traditional demographic emphasis on the female partner. F. F. Polansky and E. J. Lamb, ' Do the results of semen analysis predict future fertility? A survival analysis study', Fertility and Sterility, 49 (1988), pp. 1059-1065. z There is a lag of approximately 10-14 days between fertilization and implantation. H. M. Weitlauf. ' Biology of implantation ', in The Physiology of Reproduction, vol. 1, edited by E. Knobil, J. D. Neill, L. L. Ewing, G. S. Greenwald, C. L. Markert, and D. W. Pfaff (New York, 1988). 3 j..p. Bendel and C. Hua, 'An estimate of the natural fecundability ratio curve', Social Biology 25 (1978), pp. 210-227.",
year = "1990",
month = nov,
day = "1",
doi = "10.1080/0032472031000144846",
language = "English (US)",
volume = "44",
pages = "447--467",
journal = "Population Studies",
issn = "0032-4728",
publisher = "United Nations Publications",
number = "3",
}