In contrast, the study also found that older fathers, at the age of 40 and older, were not associated with an increased risk for babies who affected by these problems. The results were independent of the age of the mother or the mother's other factors that might be expected to have an influence the results of the birth.
The research results, which will be published in Europe's leading trade journal Human Reproduction fertility, is the largest study of the effects of paternal age on the negative results of the birth. The researchers from the Ottawa Health Research Institute, Canada, the data from the National Center for Health Statistics for virtually all births (99%) in the United States between 1995-2000 - a cohort of more than 23.6 million births. From these they looked at 2614966 singleton babies born to married women living without prior childbearing stories, aged between 20-29, where there was extensive information about his father's age, race, maternal education, prenatal care, pregnancy and Birth weight.
They chose women between the ages of 20-29, because they were the least likely to be affected by the fertility problems, some of which may have negative impact on the outcome of the birth. Since it is already known that fathers between the ages of 20-29 have the lowest risk of adverse birth outcomes, the researchers in this age group (the reference group) to compare all other age groups.
Compared with the reference group, and after adjusting for accompanying factors (such as race, education, smoking and alcohol consumption during pregnancy, the adequacy of prenatal care and the sex of the baby), babies born to teenage fathers (age less than 20) were more likely to be born prematurely (15% increased risk), have a low birth weight (13% increased risk), small for gestational age (17% increased risk), have a low Apgar score (13% higher risk) or to die within the first four weeks after birth (22% increased risk) or to die, in the period from four weeks to one year after birth (41% increased risk), but in all cases the absolute risk the death less than 0.5%. Fathers at the age of 40 years do not have an increased risk of these adverse outcomes of birth.
One of the authors of the study, Professor Shi Wu Wen, a senior scientist at the Ottawa Health Research Institute and professor at the University of Ottawa, said: "Our study suggests that a teenager's father was an independent risk factor for the negative birth outcomes, advanced paternal Age was not the case. paternal influence of the young fathers about adverse birth outcomes clearly warrants further investigation, and can lead to a deeper understanding of the causes of these results.
"Although the increased relative risks for most results were small, the degree of risk to society could be huge, because the number of births worldwide, when the increases were we are really on the paternal age."
The study looked at babies born to fathers in seven age groups, from teenagers to the aged 50 and older, and Prof. Wen said, along with the size of the study and the limited reach of the age of the mothers, meant that the results Goods to be hardly affected by coincidence or ancillary factors. However, there was no information on the socio-economic status and lifestyle of the fathers, and that could have an influence.
"The mechanisms by which a teenage father may be an increased risk of adverse birth outcomes effects are not clear," said Prof. Wen "Both biological and socio-economic status could play some roles in the observed results."
Previous studies have shown that younger men can have lower sperm count, semen volume, total number of sperm and the percentage of sperm disturbing. Immature sperm can be used with negative outcomes of birth, possibly as a consequence of the abnormal formation of the placenta in the uterus (placentation).
"It's biologically plausible that paternal age may play a role in the risk of adverse effects associated with the birth of abnormal placentation results," said Prof. Wen
However, there is also the possibility of social explanations. "Young fathers tend to come from economically disadvantaged families and have a lower education level. Socio-economic factors such as education and occupation are known to be associated with a variety of health consequences. People from less affluent background are less likely to use Pränatalen care services, which is associated with an increased risk of adverse birth outcomes, "said Prof Wen.
Other social factors that could play a role, perhaps by the deterioration of the health of the mother, including domestic violence, lack of financial or emotional support, paternal illegal drug use, smoking and alcohol consumption. "These are far more teenage fathers, and previous studies have found associations between smoking and paternal alcohol and adverse reproductive outcomes," he said.
From the finding that older fathers were no longer to have babies, the birth of unwanted results, Prof Wen said, "In our study, we did not find an association between older fathers and the increased risk of adverse birth outcomes. We could not The possibility that older fathers, married women aged 20-29 years without childbearing history perhaps a higher socio-economic status than those of our control. Beneficiaries The socio-economic conditions could offset some biological risk for adverse outcomes associated with the birth of older fathers . "
Prof Wen said that he and his colleagues were planning a pre-design study on the paternal and maternal factors that may affect the health of children, including the paternal age.
Source: Emma Mason
European Society for Human Reproduction and Embryology
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