Annually, ∼1.1 million neonates die of complications of preterm birth. Improved care and policy changes have reduced preterm mortality in high-income countries, but this care is not widely available in many low- and middle-income countries. This study was undertaken to analyze multicountry trends in preterm birth rates for 2000 to 2010, to estimate the potential reduction in preterm birth with full implementation of interventions, and to consider preterm birth reduction targets for these countries.
A statistical model was used to estimate preterm birth rates in 2010 for 184 countries with more than 10,000 live births. Data from the 65 countries in the developed, Latin America, and the Caribbean MDG regions were used for 2000 to 2010. Of 47 countries with a “very high human development index” (VHHDI), 39 were included; 2010 preterm birth rates were used as the baseline. The average annual rate of change (AARC) of preterm birth rate for different time periods was determined. A projection of potential reduction in preterm births was used to estimate the reduction in countries with VHHDI if all countries achieved the same as those with the greatest reduction in preterm birth rates for 1990 to 2010, 2000 to 2010, and 2005 to 2010. The AARC for the 2 countries with the highest rate of reduction during each period was used to project preterm birth rates for 2010 to 2015 for all countries with VHHDI. Three interventions had a high level of evidence (smoking cessation, progesterone, and zinc supplementation), but only smoking cessation and progesterone were recommended for implementation to prevent preterm birth and were included in the analysis. Economic cost savings associated with reduction in preterm birth rate were calculated using the projected number of preterm births averted for every country and the incremental cost associated with every preterm birth.
The estimated 2010 preterm birth rates varied from 5.3 per 100 to 14.7 per 100 live births in countries with VHHDI. From 2000 to 2010, preterm birth rates increased for most of the VHHDI countries. These countries also showed a leveling off of preterm birth rates from 2005 to 2010, as shown by an increasing proportion of countries (>60%) with stable (0.5% to −0.5%) or decreasing (<−0.5%) preterm birth rates compared with rates for 2000 to 2005 and 2005 to 2010. National trends in preterm birth rates were a poor predictor of future trends. The 2015 preterm birth rate for every country was estimated, assuming each followed its historic AARC for 2000 to 2010 and 2005 to 2010, or as being stable since 2010. No consistent pattern was identified. The average preterm birth rate was projected for all countries with VHHDI for 2010 to 2015. From the 2010 baseline to 2015, the projection resulted in ∼5% relative reduction in preterm birth rate by 2015, similar to the relative reduction of about 5% in the intervention analysis. The preterm birth rate in the United States increased from 10.6% to 12.5% between 1989 and 2004 and resulted from 7 “drivers”: increasing maternal age, maternal race, assisted reproductive technology and ovulation induction, non–fertility-related multiple gestations, nonmedically indicated induction plus cesarean section, stillbirths averted, and others. Only ∼50% of the change in preterm birth rate between 1989 and 2004 can be explained by these 7 drivers, with nonindicated cesarean delivery and labor induction together accounting for about 20% of the change. The potential effect of existing interventions in lowering preterm birth rates focused on 5 interventions: smoking cessation, progesterone, cervical cerclage, decreasing nonmedically indicated labor or cesarean delivery induction, and decreasing multiple births from assisted reproductive technologies. In 39 countries with VHHDI, by applying these 5 interventions, preterm birth rates will have a relative reduction of an estimated 5%, corresponding to a change in absolute preterm birth rate from 9.6% to 9.1%; 50% of the impact would be from reduction of nonmedically indicated cesarean delivery and induction of labor. If a 5% relative reduction were achieved by the included countries, about 58,000 preterm births could be averted annually, amounting to roughly US $3.0 billion in cost savings. However, major costs and burdens would remain, highlighting the need for new preventive interventions against preterm birth with greater impact.
Little reduction in preterm birth rates is currently possible. Even with assumed optimum coverage of these interventions in countries with VHHDI, the potential reductions in preterm birth rates are small. With improved classification for the causes of preterm birth, leading to better diagnosis and risk stratification, and development of new prevention strategies, perhaps the new interventions can be translated from high-income countries to the rest of the world where the burdens of preterm birth are even more onerous.