The age-related decline in female fecundity: a quantitative controlled study of implanting capacity and survival of individual embryos after in vitro fertilization.
OBJECTIVE
To determine strictly comparable rates per embryo of implantation and birth of a baby related to the woman's age, which would be representative of natural fertility at least in relative terms.


METHODS
Comparative study of IVF-ET results controlling for confounding variables including cause and duration of infertility, history of previous pregnancy, hormonal treatment, rank cycle of treatment, and numbers of embryos transferred and available.


METHODS
University comprehensive fertility service.


METHODS
All couples (n = 561) in their first cycle of treatment reaching oocyte collection, women with normal uterus and ovulatory cycles, and men with normal sperm.


METHODS
Standardized methods of pituitary desensitization, ovarian stimulation, and IVF-ET, and maximum of three embryos transferred.


METHODS
Oocytes, pregnancies, and live births per cycle; fertilization and cleavage rates; embryo implantation and live baby rates.


RESULTS
The numbers of oocytes and consequent embryos declined with age but fertilization and cleavage rates rose slightly. Embryo implantation rates were reduced when no more than three embryos were available (9.3 percent), especially in women aged 35 to 39 years (6.2 percent) or older compared with four or more embryos (17.1 percent) but were equally low in all women over 40 years even with more embryos (6.1 percent). In the age bands 25 to 29, 30 to 34, 35 to 39, and 40 to 44 years, the rates per embryo of implantation were 18.2 percent, 16.1 percent, 15.3 percent, and 6.1 percent, respectively, and of a live baby were 15.7 percent, 12.1 percent, 12.0 percent, and 3.5 percent.


CONCLUSIONS
Embryo implanting ability and survival decline gradually after 30 years of age, but by more than two thirds after 40 years and in younger women with reduced ovarian capacity.
Hull
M G
MG
University of Bristol, United Kingdom.
Fleming
C F
CF
Hughes
A O
AO
McDermott
A
A
D000328:Adult; D000375:Aging / Q000502:physiology*; D010064:Embryo Implantation / Q000502:physiology*; D004624:Embryo Transfer; D005260:Female; D005298:Fertility / Q000502:physiology*; D005307:Fertilization in Vitro; D006801:Humans; D007231:Infant, Newborn; D007247:Infertility, Female / Q000503:physiopathology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D010053:Ovary / Q000503:physiopathology; D011247:Pregnancy