Smoking Reduces Fertility In The Next Generation
For decades, smoking cigarettes has been heavily linked to foetal abnormalities. This is common knowledge but a new link has recently been discovered. According to research by the University of Copenhagen, men who were exposed to a significant amount of cigarette smoke whilst they were embryos in the womb are likely to have lower rates of fertility. The heavier the smoker, the more significant is the decrease in sperm concentration. This even extends to a reduction in testis size. Unfortunately, female foetuses suffer similar consequences from cigarette smoke, although they are much less vulnerable.
The toxins in the smoke were shown to have a direct effect on the growing male foetus, especially during the development of the sexual organs. During the intake of smoke, the number of cells in the foetal gonads was halved. What is still unknown is whether this inhibition of growth was permanent or temporary. The consequences regarding testes size and devalued sperm quality suggests that fertility will be heavily affected.
How Smoking Affects Male Embryos
The toxin greatly associated with this phenomenon is Benzypyrene (BaP) and it is known for its ability to modulate hormones. Previous attempts at exploring this relationship have tested for the harmful qualities of BaP on mice. The male children from the mother, who had been exposed to BaP (thereby mimicking the action of cigarette smoke), had significantly lighter testes. On top of this, the sperm-carrying vessels had wasted away.
Another hormone, hCG (human Chorionic Gonadotrophin) is responsible for the development of the testes and masculinisation. Males exposed to cigarette smoke in utero (within the uterus), were shown to have decreased levels of this vital hormone. In summary, smoking during pregnancy leads to a drop in hCG. A drop in hCG then slows down the process of masculinisation, a vital step in the development of male foetuses.
Unfortunately, the precise way in which these two chemicals act upon the testes is still unknown. Nor do we know how long lasting this effect is. All we are aware of is that there is a link between pre-natal sexual development and smoking.
Smoking Reduces Fertility In The Current Generation Too
As well as these effects on the foetus, here at the Concept Fertility Clinic we recommend that couples who smoke should try to stop for their own fertility reasons. There is strong evidence of it reducing fertility potential in women and reducing semen quality in men. Many NHS clinics will not treat couples unless both partners have stopped smoking for at least 6 months for these very reasons and, in general, poor sperm quality in men may mean that they need to have IVF and ICSI treatment.