Fertility and environment
Tobacco and fertility
Tobacco has a negative impact on fertility on several levels:
Tobacco and sperm
- Reduction in the quality of the sperm
Tobacco and ovarian reserve
- Reduction in the ovarian reservce
- Earlier menopause
Tobacco and In Vitro Fertilisation (IVF)
- Fewer oocytes obtained
- Fewer live births
- More miscarriages
- More ectopic pregnancies
The number of medically assisted reproduction (MAR) failures therefore increases for patients who smoke.
Medically Assisted Reproduction does not correct exposure to tobacco.
Mobile phones and fertility
The impact of exposure to mobile phones on sperm
In vitro and in vivo studies suggest a negative effect on the quality of a man's sperm from exposure to a mobile phone.
Exposure to mobile phones could be associated with an 8% reduction in sperm mobility and a 9% reduction in their survival.
Meta analyses are still needed however to validate all this data!
Exposure to mobile phones on female reproductive cells
Studies carried out appear to show a reduction in ovarian reserve in groups of women exposed to electromagnetic waves.
Risk of miscarriages
Studies would suggest a link between exposure to mobile phones and early miscarriages.
Our children's fertility and mobile phones
It is important to alert adolescents to the potential dangers of exposure to mobile phones on their future fertility.
We do not yet know much about this potential reality but it could have detrimental effects for our future generations.
Age and fertility
In Western countries, for societal reasons the age at which people have their first pregnancy is rising progressively.
However, the optimum age for fertility is still between 18 and 31 years old and reduces with time.
This decline sharpens at around 35 years old and falls dramatically at around 40.
Reduction in chances despite MAR
In Vitro Fertilisation (IVF) does not always provide an answer to a reduction in ovarian quality.
The quality and quantity of the oocyte reserve reduces with a woman's age.
Obesity and fertility
Male obesity
Body Mass Index (BMI) has an effect on the quality of the sperm.
Male obesity = a reduction in terms of the sperm's quality parameters.
Female obesity
A too high BMI causes a reduction in the number of pregnancies through In Vitro Fertilisation, a reduction in live births, an increase in miscarriages and an increase in the time taken to conceive.
Endocrine disruptors and fertility
What is an endocrine disruptor?
It is an exogenous substance (or mixture) that alters the function of the endocrine system and which, consequently, has adverse effects on the health of an intact organism, or on its descendants or sub-population.
What are these endocrine disruptors?
In industry
- Dioxines, Polychlorinated Biphenyls (PCBs)
- Nonylphenols
In agriculture
- Pesticides, insecticides: DDT, Lindane, Methoxychlor
- Herbicides, fungicides: Atrazine, Vinclozolin
- Phytoestrogens: Genistein, Coumestrol
At home
- Plastics: Phthalates
- Resins, plastics: Bisphenol A
- Insulation Polybrominated biphenyls
- Cosmetics: Parabens
- Contraception: synthetic oestrogens
What is the impact of endocrine disruptors on our fertility?
In men:
- A reduction in the fertility and the quality of the sperm with considerable geographical variations.
- For unborn boys: an increase in hypospadias, cryptorchidism and testicular cancer. This trio, known as gonadal dysgenesis, is probably caused by an early deficit in androgenisation.
- The life of the foetus is a window of sensitivity to the effects of endocrine disruptors on spermatogenesis.
- An increased risk with inactivity and obesity.
In women:
- Puberty seems to be starting earlier and earlier. This increase in early puberty could be due to endocrine disruptors.
- There is still very little proof of the effect of endocrine disruptors on folliculogenesis (the development of follicles) in humans, however data from rodents suggests such effects.
Caffeine and fertility
A rise in the number of miscarriages has been caused by excess caffeine consumption in women in the periconceptional period.
Excess of caffeine consumption by the future father may also be linked to a rise in the number of miscarriages.