Complex sentence: The Norwegian survey also indicated that parents with an immediate fertility intention are more likely to realize it during the first two years; after four years, the fertility rate was higher among those intending to have children in the long term.
Split into simpler sentences: The Norwegian survey also indicated that parents with an immediate fertility intention are more likely to realize it during the first two years. In contrast, after four years, the fertility rate was higher among those intending to have children in the long term.