Increasing paternal age is associated with delayed conception in a large population of fertile couples: evidence for declining fecundity in older men

Abstract

The impact of male age on fecundity remains controversial. Here, a large population study was used to investigate the effect of paternal age on time to conception. All couples in the Avon Health district expecting a baby between 1 April 1991 and 31 December 1992 were eligible. Questionnaires completed by both the man and the woman at 18 weeks gestation covered specific fertility factors, e.g. parity, paternity, cohabitation and oral contraception; and non-specific factors, e.g. educational achievement, housing, cigarette smoking, alcohol consumption, obesity. Logistic regression was used to identify factors independently related to conception in < or =6 or < or =12 months. Of 8515 planned pregnancies, 74% were conceived in < or =6 months, 14% in the second 6 months and 12% after more than a year. Nine variables, including the age of the woman, were independently related to time to conception. After adjustment for these, the likelihood of conception within 6 or 12 months was lower in older men. Compared to men <25 years old, the adjusted odds ratios (95% confidence interval) for conception in < or =12 months were 0.62 (0.40, 0.98), 0.50 (0.31, 0.81) and 0.51 (0.31, 0.86) in men aged 30-34, 35-39 and > or =40 years respectively.

The effects of advanced paternal age on fertility

“…46 An Australian study looking at 585 couples found an increased risk of infertility in couples where the male partner was .35 years old, compared with couples in which the male was ,35 years old. 48 In cases when intrauterine insemination was used to achieve pregnancy and female age was controlled, a paternal age of greater than 35 years was associated with a 50% lower pregnancy rate compared with that when the male was less than 30 years old. 49 A similar dependence on maternal age was observed in a study on 6188 randomly-selected women in which a paternal age of greater than 40 years was found to be a risk factor for infertility in women age 35 years or more.…”

“…6 Indeed, paternal information is often missing from the birth certificate and the age of the father is not reported in 14% of all births. 6 In those cases where the paternal age was reported, the rates of live births per 1000 men increased from 6.1 in 1980 to 8.2 in 2007 among men aged [45][46][47][48][49] years. 6 These statistics are mirrored in advanced countries around the world.…”

Paternal age and reproduction

“…However, only couples after the 36th week of pregnancy (n ¼ 10 886) were included, probably causing an exclusion or underrepresentation of less fecund or sterile couples . In the British Avon Longitudinal Study of Pregnancy and Childhood (ALSPAC) study Ford et al (2000) evaluated the probability of conceiving within 6 or 12 months and found a lower likelihood of conception in couples with older men [after adjustment for nine other variables independently related to TTP (including maternal age)]. Of 8515 planned pregnancies reaching at least 24 weeks of gestation, 74% were conceived in 6 months, 14% during the second 6 months and 12% after more than a year.…”

Effects of age on DNA double-strand breaks and apoptosis in human sperm

“…Although age-related changes in the male reproductive system are universally recognized, the question of declining fecundity with male age is controversial (16). Among couples who ultimately conceive, a man aged Ͼ35 years has twice the likelihood of requiring more than 12 months to impregnate his female partner than does a man aged Ͻ25 years (16).…”