The 1960s had a big baby boom as a result of women born in the 1940s having more children and having them earlier. The standardised mean age at delivery for women born in 1945 in England and Wales was roughly 25.5 years, with an average family size of 2.19. This means that on average, women were having babies at their most fertile age. For those who didn't deliver before the end of 1959, the mean age at delivery rose by about six months, to 31.4 years. The increase in fertility rates was particularly high among younger women. By 1969, one in four births occurred to women under 30. After declining slightly, the birth rate for girls aged 15-19 began to rise again, back to where it was in 1950. The increase in maternal mortality was also very high during this time. In 1965, 595 women died during or following childbirth, which was nearly twice as many as the 275 deaths reported in 1955. The higher death rate was mainly due to increased risks for pregnant teenagers and women in poor health. There were several factors that led to more young people starting families during the 1960s. One reason is that social security systems improved so women could work while pregnant or after giving birth. Prenatal care also became widely available through free clinics and hospitals, so mothers did not have to worry about paying fees. Additionally, contraception became more accessible and affordable.