Complex sentence: Illegitimacy became more socially discouraged, with first pregnancies outside of marriage declining from 40% to 20% during the Victorian era, at the start of the 21st Century, the figure was back up to 40%.
Split into simpler sentences: Illegitimacy became more socially discouraged, with first pregnancies outside of marriage declining from 40% to 20% during the Victorian era. At the start of the 21st Century, the figure was back up to 40%.