Kazemier B M, Miller E S, Grobman W A, Mol B W J
Department of Obstetrics and Gynecology, Academic Medical Center, Amsterdam, The Netherlands.
Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
J Perinatol. 2016 Jul;36(7):516-21. doi: 10.1038/jp.2016.12. Epub 2016 Feb 25.
To examine variation in preterm birth (PTB) rates between nulliparous women from two different populations and to investigate the contribution of short cervical length to any observed variation.
A comparative study between two cohorts of singleton nulliparous women from the Netherlands and Chicago, USA was performed. Women with a non-anomalous singleton pregnancy who underwent routine transvaginal cervical length measurement between 16+0 and 21+6 weeks of gestation with a known pregnancy outcome were selected. Fetuses with congenital anomalies, intrauterine fetal deaths and deliveries before 24+0 weeks were excluded. Total, spontaneous and iatrogenic PTB rates were calculated for both populations and compared with univariable and multivariable logistic regression.
We included 3409 women from the Netherlands and 3334 women from Chicago. The median cervical length was slightly lower in the Netherlands compared with Chicago (42 vs 44 mm, P<0.0001), but the rate of cervical length of ⩽25 mm was comparable (0.9% vs 0.8%, P=0.69). The total rate of PTB prior to 37 weeks was comparable between locations (8.0% in the Netherlands vs 7.3% in Chicago, P=0.27) but PTB prior to 32 weeks was higher in the Netherlands (1.3% vs 0.5%, P=0.002). Multivariable regression revealed that women from the Netherlands, compared with women from Chicago, are at increased risk for spontaneous PTB between 24 and 27 weeks and between 28 and 31 weeks (adjusted odds ratio (aOR) 5.3, 95% confidence interval (CI) 1.5 to 19 and 3.1, 95% CI 1.2 to 8.3, respectively). In contrast, the number of late spontaneous PTB between 34 and 36 weeks did not differ between both populations (4.1% vs 4.3% aOR 1.1, 95% CI 0.87 to 1.5).
Despite similar percentages of short cervix, there are marked differences in early PTB rates between the Netherlands and Chicago, possibly indicating different phenotypes of PTB. A high frequency of spontaneous early preterm birth is not always accompanied by an increase in the frequency of a short cervix.
研究来自两个不同人群的初产妇早产（PTB）率的差异，并调查宫颈短对任何观察到的差异的影响。
对来自荷兰和美国芝加哥的两个单胎初产妇队列进行了一项比较研究。选择在妊娠16+0至21+6周期间接受常规经阴道宫颈长度测量且妊娠结局已知的单胎妊娠无异常的妇女。排除有先天性异常、宫内胎儿死亡及妊娠24+0周前分娩的胎儿。计算两个人群的总早产率、自发性早产率和医源性早产率，并通过单变量和多变量逻辑回归进行比较。
我们纳入了3409名来自荷兰的妇女和3334名来自芝加哥的妇女。荷兰的宫颈长度中位数略低于芝加哥（42 vs 44 mm，P<0.0001），但宫颈长度≤25 mm的比例相当（0.9% vs 0.8%，P=0.69）。37周前的总早产率在两个地区相当（荷兰为8.0%，芝加哥为7.3%，P=0.27），但荷兰32周前的早产率更高（1.3% vs 0.5%，P=0.002）。多变量回归显示，与芝加哥的妇女相比，荷兰的妇女在24至27周以及28至31周之间发生自发性早产的风险增加（调整后的优势比（aOR）分别为5.3，95%置信区间（CI）为1.5至19；3.1，95%CI为1.2至8.3）。相比之下，34至36周之间晚期自发性早产的数量在两个人群中没有差异（4.1% vs 4.3%，aOR为1.1，95%CI为0.87至1.5）。
尽管宫颈短的比例相似，但荷兰和芝加哥之间早期早产率存在显著差异，这可能表明早产的不同表型。自发性早期早产的高频率并不总是伴随着宫颈短频率的增加。
