Human Reproduction, Vol. 14, No. 2, 572B-573,
February 1999
© 1999 European Society of Human Reproduction and Embryology
Letters to the Editor |
Selective cost of delayed childbearing
Department of Genetics and Microbiology, University of Pavia, via Abbiategrasso 207, 27100 Pavia, and 2 Department of Genetics and Molecular Biology, University La Sapienza, ple Aldo Moro 5, 00185 Roma, Italy
Dear Sir,
In recent years the tendency to postpone marriage and childbearing has spread throughout the developed countries, giving rise to a debate on its social and biological consequences (Bowman and Saunders, 1995
; Gosden and Rutherford, 1995; Lansac, 1995; Breart, 1997). Here we wish to draw attention to the fact that in spite of the very low risk of perinatal mortality, since the beginning of the eighties when maternal age at delivery started to increase, women have paid a not negligible price in perinatal deaths.
From 1980 to 1994, year of the latest available data from the Italian vital statistics bureau (ISTAT), in Northern and Central Italy the average maternal age at delivery and the proportion of aged (
35 years) mothers increased steadily, and linearly from 1985 onwards: the average age increased from 27 to 30 years, and the proportion of aged mothers by about 70%. During the same period the overall stillbirth rate decreased drastically, but among the aged mothers, in spite of a 60% reduction, it remained higher than that among mothers <35 years, and in 1994 had not yet reached the stillbirth rate suffered by the young mothers ten years earlier (Table I).
|
We calculated in terms of stillbirths the selective cost of late childbearing among the women aged
35 years in excess of a 9% baseline proportion of mothers 35: this 9% low, reached in 1980 thanks to the reduction in the number of children per family, was assumed to be the minimum unavoidable proportion of mothers who would have a late pregnancy. In the 10 years from 1985 to 1994, the excess quota accounted for a total of >100 000 mothers (50 000 in the last 4 years of the study), 700 of whom lost their child at birth and an almost idential number lost their child within the first month of extra-uterine life (Table I
). The emotional price of the losses is even greater in northern and central Italy where women have attained the lowest fertility (1.05 children per woman in 1994) among the EU countries.
The apparently low perinatal death figures are the tip of the iceberg; the personal and social cost that the tendency to delay parenting is exacting is greatly underestimated if only child mortality is considered. Fertility as well as the quality of the conceptus sharply decreases with advancing parental age, fetal losses increase twofold in aged with respect to young mothers (Fretts et al., 1995; Lansac, 1995) and despite the progress in antenatal diagnosis a greater frequency of genetic anomalies is reported among children born to parents aged >35 years (Lansac, 1995; Breart, 1997).
If no socio–cultural change perturbs this tendency, its cost is expected to increase (percentage of aged mothers, –993.003 +0.506 year according to the fitted linear regression; >25% of childbearing women will be aged 35 years by 2015, that is in less than one generation.
The decision to start a family late may allow greater parental awareness in pregnancy management and child raising, but might be a disadvantageous gamble from a personal and social point of view. Only personal consciousness of the risk and a far-seeing policy of incentives for young couples to start a family may counterbalance the tendency and limit personal and social costs to those instances of subfertility and perinatal pathology which are unavoidable.
Notes
3 To whom correspondence should be addressed 
References
Bowman, M. and Saunders, D.M. (1995) Are the risks of delayed parenting overstated? Hum. Reprod 10, 1035–1036.
Breart, G. (1997) Delayed childbearing. Eur. J. Obst. Gynecol. Reprod. Biol. 75, 71–75.[Web of Science][Medline]
Fretts, R.C. et al. (1995) Increased maternal age and the risk of fetal death. N. Engl. J. Med., 333, 953–957.
Gosden, R and Rutherford, A. (1995) Delayed childbearing. Br. Med. J., 311, 1585–1586.
Lansac, J. (1995) Delayed parenting. Is delayed childbearing a good thing? Hum. Reprod., 10, 1033–1035.
CiteULike 
Connotea 
Del.icio.us What's this?
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||