The effectiveness of medical interventions aimed at preventing preterm birth: a literature review

Background

Preterm birth is a significant global health problem with serious short and long term consequences. This paper reviews the research literature to answer the question how effective are the medical interventions that aim to reduce the rates of preterm birth?

Methods

A systematic search was carried out in CINAHL, Cochrane, Medline and Embase in relation to following medical treatments aimed at preventing preterm births: anti-infective medications, tocolytics, progesterone and cervical cerclage. The research underpinning each type of intervention is critically analysed in order to establish the validity of knowledge claims that are made for each type of intervention.

Findings

In relation to reducing the rates of preterm births, anti-infectives are only effective in the presence of known infection. Screening for infections during pregnancy is ineffective. Tocolytic agents are not effective in decreasing the preterm birth rates. Progesterone seems to be effective in a select group of pregnant women at higher risk of preterm birth. Cervical cerclage plays a small and an occasional role in preventing some preterm births.

Conclusions

This literature review demonstrates that medical interventions aimed at preventing, not just delaying, preterm birth, are not effective at a population level. Providing holistic, antenatal midwifery care for women living in socio-economic disadvantage and/or with an increased risk of preterm birth seems to be a promising strategy to address the negative effects of the social determinants of disease and thus to reduce the rate of preterm births at an individual and a population level.     

Sex hormones and choice under risk

We study the correlation of choice under risk in Holt–Laury lotteries for gains and losses with gender, the use of hormonal contraceptives, menstrual cycle information, salivary testosterone, estradiol, progesterone, and cortisol as well as the digit ratio (2D:4D; length of the index finger to the ring finger of the right hand) in more than 200 subjects (45% females). In males, salivary testosterone is negatively correlated with risk aversion for gains only. In females, salivary cortisol is positively correlated with risk aversion for gains only. No other significant correlations between risk preferences and salivary hormones are observed. No significant correlations between risk preferences and the menstrual cycle are observed in naturally cycling females. No significant correlations between risk preferences and the digit ratio are observed in either gender and/or race.