Preterm birth is the leading cause of childhood disability and infant mortality in the developed world. The rate of preterm birth has been increasing in recent decades for reasons which are poorly understood. The rate of preterm birth is approximately 8% in the UK, 12% in the USA and 20% among African Americans.

The risk of preterm birth is highest for older mothers (greater than 35 years) and teenagers. There is a moderate association with marital status of parents in Europe and the USA, and a somewhat weaker association with poverty.

Witt et al (AJPH 2104) reports, from a US cohort, a high rate of preterm birth to teenage mothers and a four fold increased risk of preterm birth for teenage mothers who had experienced pre-conception stressful life events compared to those who had not.

There is a strong linear correlation for historical rates (up to 1972) of birth to unmarried parents with current rates of preterm birth in US states r greater than 0.65, p=0.000 (cdc data, correlation unpublished).

Goodman and Greaves (IFS 2010) report, from the MCS, a 4x and 3x relative risk of parental separation for cohabiting versus married parents when their children were 3 and 5 years old. Parental separation was a significant adverse influence on cognitive and social development in the children. There are also studies which report associations of family structure with rates of smoking and obesity. These are recognised risk factors for preterm birth.

There is empirical evidence that early life experiences influence the risk of preterm delivery for young mothers. Longitudinal studies could reveal how birth circumstances, including the marital status of parents, influence the likelihood of becoming a teenage mother and how they affect the risk of preterm birth in young mothers.

This information may carry the potential for clinical benefits, such as the identification and support of women with high risk pregnancies, and assist in the development of strategies for the prevention of both teenage pregnancy and preterm birth.