Risk factors for medically indicated preterm birth in a Latin American population

描述（由申请人提供）：早产是全球新生儿和婴儿发病率和死亡率的主要原因之一。在乌拉圭，早产占所有出生人数的11.8%，并且与大多数新生儿死亡和严重新生儿发病率以及长期发病率有关。拉丁美洲的一些研究表明，由于医学上显示的早产增加以及人口风险因素的变化，早产率在过去几年中明显增加。本研究的主要目的是确定乌拉圭低社会经济地位（SES）人群中早产的风险因素，并与同一人群中自发性早产和胎膜早破（PPROM）早产的风险因素相比，检查医学指示早产的风险因素。我们假设，医学指征性早产的危险因素与自发性早产和PPROM的危险因素不同。这种差异的存在被认为是支持这样一种假设，即医学上指示的早产是一个不同的实体，当研究人员接近早产的话题时，应该与其他两种早产亚型分开。拟定的研究是一项基于人群的病例对照研究，其中病例将定义为医学指征早产、自发性早产和PPROM，对照将涉及足月分娩。在40个月的时间内，本研究将招募约1，280例早产（病例）和2，560例足月分娩（对照）。所有被招募的妇女都将有一份完整的问卷，旨在收集有关具体风险因素的数据。每例病例将选择两个对照，本病例对照研究的创新之处在于，从早产分娩当天随机选择一个对照（传统对照选择），从相应病例的预产期随机选择第二个对照（新拟定对照）。这两种类型的对照的比较将提供一个很好的机会，研究方法的问题，尚未接近在医学文献中，关于控制选择围产期病例对照研究。这项研究的主要目的将有助于确定可改变的风险因素，以设计预防计划和未来可能的策略，从而降低早产率。本研究计划的长期目标是根据拟议研究中确定的风险因素制定干预策略，从而降低发病率和死亡率。

DESCRIPTION (provided by applicant): Preterm birth is one of the main causes of neonatal and infant morbidity and mortality worldwide. In Uruguay, preterm birth accounts for 11.8% of all births and it is associated with the majority of neonatal deaths and severe neonatal morbidity, as well as with long-term morbidity. Some studies in Latin America have shown that preterm birth rates have notoriously increased during the last years as a consequence of the increase of medically indicated preterm births as well as population risk factors changes. The main objective of this study is to determine the risk factors for preterm birth in the low social economic status (SES) population from Uruguay and to examine the risk factors for medically indicated preterm births compared to the risk factors for spontaneous preterm births and for preterm births with premature rupture of membranes (PPROM) in the same population. We hypothesize that the risk factors for medically indicated preterm birth are different from the risk factors for a spontaneous preterm birth and PPROM. The existence of such differences is to be considered supportive of the hypothesis that medically indicated preterm birth is a different entity that should be separate from the other two subtypes of preterm births when researchers are approaching the topic of prematurity. The proposed investigation is a population-based case-control study in which cases will be defined by medically indicated preterm births, spontaneous preterm births and PPROM, and the controls will involve term births. During a period of time of 40 months, approximately 1,280 preterm births (cases) and 2,560 term births (controls) will be recruited in this study. All women recruited will have a complete questionnaire designed to collect data about specific risk factors. Two controls will be selected per each case, and an innovation of this case-control study will be that one control will be randomly selected from the same day of the preterm birth's delivery (traditional control selection) and a second control will be randomly selected from the due date for the corresponding case (newly proposed control). The comparison of both types of controls will offer a great opportunity to study a methodological issue that has not been yet approached in the medical literature, regarding control selection in perinatal case-control studies. The primary aims of this study will help identify modifiable risk factors to design prevention programs and possible future strategies to potentially reduce preterm birth rates. The long-term goal of this research program is to develop intervention strategies that are based on the risk factors identified in the proposed study resulting in decreased morbidity and mortality.