1981/01/01 by Jane Menken, James Trussell, Susan Watkins · 2 citations
Medicine · #Birth, Development, and Health #Ovarian function and disorders #Assisted Reproductive Technology and Twin Pregnancy
paper · doi:10.2307/203626
The determinants of age-specific marital fertility rates in non-contracepting populations are discussed and the physiological link between nutrition and reproduction in women who are chronically malnourished rather than famished are examined. Initial attention is directed to menarche and menopause for these set the outer bounds to the time of childbearing. This is followed by a discussion of the determinants of birth interval. Birth interval and its components are of primary concern because if populations are to fit different numbers of births into similar childbearing spans the intervals between these births must vary. There is reason to believe that the age of menarche might be affected by the level of nutrition. In some countries where nutrition has remained inadequate the age of menarche is comparatively high. Like the age at menarche the age at menopause is likely to have had little influence on overall fertility in Europe. The meager evidence available suggests that the mean age at last birth appears to vary little among populations which do not practice birth control. The length of postpartum anovulation the period after a birth when there is no ovulation is a primary determinant of variation in the length of the birth interval. Research in which the direct measurement of the duration of breastfeeding was possible found that breastfeeding was the primary determinant of the length of postpartum amenorrhea. Researchers in Bangladesh and in Guatemala have found a slight negative relation between nutritional status and the duration of postpartum amenorrhea.