ABSTRACT
Introduction It is clear from epidemiological and experimental studies that adverse periconceptional lifestyles significantly contribute to reproductive health and performance.1 During the periconceptional period, defined as the time span before and surrounding the conception, gametes further develop and are being programmed by epigenetic mechanisms in order to achieve successful conception and subsequent embryogenesis.2 Adverse lifestyles, such as alcohol use and malnutrition, may induce alterations in the DNA sequence and in the epigenetic (re)programming of the genome.3,4 Thus, adverse periconceptional lifestyles may irreversibly affect the gametes of parents-to-be and the subsequent embryonic genome with consequences for its future health and late-onset diseases.5,6
Failure of conception due to compromised quality of the gametes or early embryo presents in the pre-conceptional period as subfertility and is defined as a failure of conception after 1 year of regular, unprotected intercourse with the same partner. Nowadays, approximately 15% of all couples experience primary or secondary subfertility at some time during reproductive life. In around 58% the cause of subfertility predominantly originates from the woman, in 22% from the man, in 5% from both partners and in the remaining 15% no clear cause can be identified.7 In the past decade it has become apparent that subfertility is an increasing problem particularly in rich countries.8
Besides the rising age of primiparae, the adverse lifestyles of the couples exerted by the increasing demands and stresses from jobs and social obligations may significantly contribute to this problem. Recent figures show that 25% and 35% of women and men in reproductive age are smoking, and 80% and 85% use alcohol, respectively.9 Furthermore, unhealthy diets, characterised by low intakes of fruits and vegetables, and high intakes of saturated fats, are also increasingly used in this age group.10 It is well known that the aforementioned lifestyles significantly contribute to the epidemic of complex diseases such as cardiovascular disease, cancer and obesity by epigenetic mechanisms.11
However, the emerging concept that the same adverse lifestyles in the periconceptional period significantly affect conception and reproductive performance with
