Paternal age >or=40 years: an important risk factor for infertility.
OBJECTIVE
The purpose of this study was to examine the risk of infertility that is associated with paternal age, because this factor rarely has been investigated, whereas maternal age of >or=35 years is a well-known risk factor.


METHODS
This large, retrospective, population-based sample included 6188 European women (from Denmark, Italy, Spain, Germany) aged 25 to 44 years who were selected randomly from census registers in 1991 through 1993.


RESULTS
Among couples composed of a woman aged 35 to 39 years, risks were significantly higher when paternal age was >or=40 years than when paternal age was <40 years, with an adjusted odds ratio of 2.21 (95% CI, 1.13, 4.33) for delay in pregnancy onset (failure to conceive within 12 months) and of 3.02 (95% CI, 1.56, 5.85) for difficulties in having a baby (failure to conceive within 12 months or pregnancy not resulting in a live birth).


CONCLUSIONS
Like maternal age of >or=35 years, paternal age of >or=40 years should be considered to be a key risk factor for infertility.
Institut National de la Santé et de la Recherche Médicale, Le Kremlin-Bicêtre, France.
Elise
E
de La Rochebrochard
Patrick
P
Thonneau
D000328:Adult; D019352:Censuses; D003718:Denmark; D005260:Female; D005858:Germany; D006801:Humans; D007246:Infertility / Q000209:etiology*; D007558:Italy; D008297:Male; D008423:Maternal Age; D010331:Paternal Age; D012189:Retrospective Studies; D012307:Risk Factors; D013030:Spain