Preterm birth (PTB) is the leading cause of perinatal mortality and morbidity. The long-term health problems associated with PTB are significant. Despite many strategies to identify and treat preterm birth and labour, there remains slow progress in reducing the rates of PTBs. The causes of PTBs are multifactorial. There needs to be a good and coordinated approach to the identification of risk factors, screening strategies and appropriate interventions to have any impact on reducing the rates of PTBs worldwide. Currently, there is no single diagnostic test that should be used exclusively to direct management in the setting of threatened preterm labour. Tests to stratify risks of PTB include biochemical markers such as fetal fibronectin and transvaginal ultrasound of cervical length. Common interventions for preterm labour include tocolysis, antenatal corticosteroids and magnesium sulphate for neuroprotection. This chapter analyses the causes and risk factors for PTB, screening strategies and preventative initiatives to prevent PTB, and reviews the evidence and current guidelines in the screening and prevention of PTB.

While there is a physiological basis for the concern about preterm birth with sex in pregnancy, this risk has not been demonstrated in retrospective and prospective studies. In fact, in low-risk patients, sexual activity is typically associated with a decrease in preterm birth. In patients with a history of preterm birth, there is also no evidence that sexual activity increases the risk of preterm birth. Sexually transmitted infections (STIs) should be avoided in pregnancy due to the well-documented increased risk of preterm birth. Notably, sexual cohabitation for 12 months prior to conception (with maternal exposure to sperm) leads to a decrease in preeclampsia and likely to the risk of preterm birth.