Fertility – the key facts at a glance

Fertilisation …

… describes the merging of the female egg with the male sperm and the fusion of the male and female genomes. Unlike other cells, both gametes (female and male) contain only half a set of chromosomes (haploid). Combining the results in a complete set of chromosomes (diploid).

Embryo or foetus …


  • First stage of development after successful fertilisation
  • Embryonic period: 8 weeks
  • Embryo particularly susceptible to external influences and malformations


  • From the 9th week after fertilisation
  • The foetal period: from the 9th week to birth

What does … actually mean?

…fertile? The ability to become pregnant spontaneously, i.e. without supportive measures

…sub-fertile? Fertility is limited, but there are still significant chances of spontaneous pregnancy.

…infertile? The inability to maintain a pregnancy.

… sterile? The inability to get pregnant at all.