Hello jmi
It is actually very difficult to find such age-specific data, because
most of the discussions tend to lump all women over 40 (or even over
35!) into the same data set. The information below is the closest
that I have been able to find. When all the sources are taken into
consideration, they do tend to show that the chances of a woman aged
48 conceiving naturally and subsequently carrying a pregnancy to term
are very, very small.
1. I have found the following statistics on the web site of the
Genesis Fertility Center at
http://www.genesis-fertility.com/facts/
“Conception rates for normal healthy couples are, at best 20-25% per
menstrual cycle. Once a woman reaches the age of 35, her fertility
begins to decline. By age 40, it is estimated that her conception rate
is in the range of 8-10% per month and at age 43, the pregnancy rate
is thought to be as low as 1-3% per month.” (According to an Italian
doctor cited in ref . 4 below, “the chances of a 50-year-old woman
becoming pregnant spontaneously amount to 0,0016 percent.")
In addition, the risk associated with pregnancy in older women was
given as follows:
Risk of miscarriage in women aged 45 and over is 53.2%
(figure cited from "Reproductive Potential in Older Women" by P.R.
Gindoff and R. Jewelewicz., published in Fertility & Sterility.
46:989;1986)
Moreover, the risk for Down Syndrome in women aged 48 is 1/14, in
women aged 49 it is 1/11. The total risk for chromosomal
abnormalities at these two ages is 1/10 and 1/8, respectively.
(Data from "Maternal Fetal Medicine: Practice and Principles" edited
by Creasy and Resnick, published by WB. Saunders, Philadelphia, PA.
1994: page 71)
2. A Danish study does actually cite the rate of miscarriage for
women aged 48 and over as being over 84%:
“Danish researchers analysed the combined effects of maternal age and
reproductive history on outcome of pregnancy in over 600,000 women
between 1978 and 1992…. The risk of a spontaneous abortion varied from
a minimum of 8% by the age of 22 years to over 84% by the age of 48
years or more, irrespective of previous reproductive problems.
Similarly, the risk of an ectopic pregnancy also increased with
increasing maternal age, from 1.4% of all pregnancies at the age of 21
years to 6.9% in women aged 44 years or more. (Report of a study
published in the British Medical Journal, as featured on the Aphrodite
Women’s Health web site
http://www.aphroditewomenshealth.com/news/20020309012356_health_news.shtml
)
3. Another estimate is given in terms of the chance a woman has of
conceiving within a year. “Sexually active women under 30 years of age
have a 90% chance of conceiving within a year. Conception rate drops
to 75% percent between the ages of 30 and 40. After the age of 40,
the conception rate drops to 25-30%, and at age 50, fertility is
essentially zero. (Source: Kirtly Parker Jones, MD, Chief of
Reproductive Endorcrinology, University of Utah School of Medicine,
Words of Wellness, Vol. XVII, No. 5)”
http://www.peiapathways.com/know/didyouknow2.htm ('Pathways to
Wellness' web site of PEIA, the West Virginia Public Employee
Insurance Agency)
4. The Mothers Over 40 web site at http://www.mothersover40.com links
to a news story about a 52-year-old woman in Italy, who gave birth to
triplets, supposedly without having any fertility treatment. Doctors
have expressed their doubts about this. According to Carmine Nappi,
the doctor who assisted at the births, “the chances of a 50-year-old
woman becoming pregnant spontaneously amount to 0,0016 percent. "A
woman who becomes naturally pregnant at the age of 50 is a rarity. But
in the case of triplets it is an absolute first," Nappi told La
Repubblica.”
http://www.iol.co.za/index.php?set_id=1&click_id=31&art_id=qw1046092320734B234
Search strategies: 1. "older women" "conception rate" 2. "older women"
"pregnancy rate" 3. "older women" fertility |
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