What are the effects of advanced age on male fertility, pregnancy process, and future fertility?

How old are males in terms of fertility?

Male fertility typically decreases with age, and many associated risks (such as smoking) also increase with age. But currently there is not so much research, and the general definition is subjective, based on age-related changes in spermatogenesis and fertility. They mostly define the male reproductive age as>40 years old.

02. What are the changes in the fertility of elderly men?

#1. Decreased semen quality:

25% of infertility is related to males. As age increases, the concentration, total number, vitality, and forward mobility of sperm all show a downward trend, but abnormal sperm morphology shows an upward trend. Due to the fact that male germ cells (sperm) undergo more mitosis than female germ cells (eggs), the replication of the genome during each cell division may introduce replication error mutations, which may lead to gene mutations, chromosomal abnormalities, etc. As we age, harmful mutations in DNA replication in sperm continue to accumulate.

#2. Decline in fertility rate:

Simply put, as men age, the time required for women to conceive increases and the pregnancy rate decreases. Research in the UK shows that men over 45 spend five times more time conceiving a woman than men under 25, and men over 40 are 30% less likely to conceive a woman within a year than men under 30.

#3. Motor function and frequency reduction:

In fact, the decrease in exercise frequency is mainly due to a decrease in motor function. However, in reality, the decline in motor function itself does not affect sperm quality or the time required for conception.

03. What are the risks for older male babies during pregnancy?

Babies are affected by various factors during pregnancy, so it is sometimes difficult to know which single cause is causing the risk. For example, it is difficult to distinguish the impact of parents on the pregnancy process. I can only roughly describe the possible risks based on existing information:

1. Abortion: Natural pregnancy abortion rate and father's age; The abortion rate of 40 year old IVF has slightly increased, but the claims are inconsistent.

2. Premature birth: Father's birth age≥ At the age of 45, the risk of premature birth increases by 13-14%; At the same time, it was found that the father's age was less than 20 years old, which also increased the corresponding risk.

3. Stillbirth: Fathers over 40 years old have an increased risk of stillbirth by 24-48%.

4. Chromosome abnormalities: We all know that the risk of Down syndrome is high in the babies of elderly mothers, so it is generally recommended to undergo amniocentesis. That's because research has found that the age of the mother is the main risk factor for chromosomal abnormalities in offspring, while the age of the father has little impact. Father's reproductive age≥ The risk of Down syndrome in a 50 year old baby is only twice that of a father<30 year old baby.

04. Does the baby of an elderly male have long-term effects after birth?

In fact, more and more people are paying attention to the long-term development of older male babies after birth. Although studies have shown that an increase in male reproductive age may increase child mortality and the risk of malignant tumors (such as leukemia and neurotumors) in children, The overall risk level of metabolic diseases (obesity, diabetes, etc.) and mental diseases (schizophrenia, autism, etc.) is not high. So I'll briefly mention it here.