北京地区早产发生现状及早产儿结局的调查分析

Preterm birth and preterm infants in Beijing regional district

目的探讨北京地区早产发生现状及不同孕周、不同类型早产儿的结局。方法选择2006年12月1日-2007年5月31日在北京大学第一医院（北大一院）、首都医科大学附属北京妇产医院（市妇产医院）、北京市海淀区妇幼保健院（海淀妇幼）、北京大学第三医院（北大三院）住院分娩的孕28周-36周“早产产妇955例及其早产儿1066例为研究对象，4家医院同期分娩数为15197例。结果（1）早产发生率：早产总发生率为6．3％（955／15197）。其中北大三院的早产发生率为13．1％（150／1142），北大一院的早产发生率为8．1％（125／1549），市妇产医院的早产发生率为5．5％（369／6656），海淀妇幼的早产发生率为5．3％（311／5850）。其中北大三院的早产发生率明显高于其他医院（P〈0．01）。两家综合医院（北大一院及北大三院）的早产率10．2％（275／2691）明显高于两家专科医院（市妇产医院及海淀妇幼）的早产率5．4％（680／12506），两者比较，差异有统计学意义（P〈0．01）。（2）早产发生孕周：〈34周的早产发生率为28．5％（272／954），t〉34周的早产发生率为71．5％（682／954），早产主要发生在孕34周以后。各家医院的早产发生孕周分布有明显不同，其中，海淀妇幼〈34周的早产发生率明显低于其他3家医院（P〈0．01），北大一院〈34周的早产发生率最高（P〈0．05），北大三院与市妇产医院相比较，差异无统计学意义（P〉0．05）。（3）早产发生的原因：在早产的发生原因排序中，未足月胎膜早破（PPROM）早产占首位（405例），其次为医源性早产（340例）和自发性早产（205例）。各医院早产发生的原因有所不同，北大三院的医源性早产率明显高于其他各医院（P〈0．01）；北大一院的PPROM发生率较高而自发性早产率较低。医源性早产的发生原因排序中前4位分别是子痫前期143例（42．0％），胎儿窘迫58例（17．1％），前置胎盘43例（12．6％），胎盘早剥33例（9．7％）。（4）各家医院的早产儿结局比较：4家医院由于早产原因、孕周不同，其早产儿结局也存在较大差异，市妇产医院早产儿死亡率最高，为5．4％（22／408），与海淀妇幼（1．3％，4／320）及北大三院（0．6％，1／170）比较，差异有统计学意义（P〈0．01）；与北大一院（2．4％，3／124）比较，差异无统计学意义（P〉0．05）。（5）不同孕周的早产儿结局比较：〈32孕周的早产儿治愈率显著低于I〉32孕周者（P〈0．01），≥34孕周的早产儿治愈率为99．6％。〈32孕周的早产分娩家属放弃及早产儿死亡率显著高于I〉32孕周者，其中，〈32孕周的早产儿死亡率为22．1％，≥34孕周者仅为0．3％，两者比较，差异有统计学意义（P〈0．01）。（6）不同原因的早产儿结局比较：医源性早产的早产儿死亡率（4．9％）高于PPROM早产（1．6％），两者比较，差异有统计学意义（P〈0．05）。PPROM、自发性早产及医源性早产3者的早产儿治愈率相互比较，差异无统计学意义（P〉0．05）。结论早产儿死亡率较高，尤其是〈32孕周的早产儿死亡率更高，这部分早产儿是早产预防的重点；同时，减少医源性早产，积极预防PPROM早产的发生也是降低早产发生率的重要因素。

Objective To investigate the incidence and relevant information of preterm birth and the outcomes of preterm infants delivered at various gestational weeks and for different causes. Methods Totally 955 women, who ended their pregnancies before term, and 1066 neonates of the previous mothers were enrolled in this survey, among 15 197 deliveries at Peking University First Hospital, Beijing Gynecological and Obstetric Hospital, Women＇s and Children＇s Hospital of Haidian District and Peking University Third Hospital, respectively, from December 1^st, 2006 to May 31^st, 2007. Results （ 1 ） Incidence of preterm birth： The overall incidence of preterm birth of the 4 hospitals was 6. 3% （955/15 197）, and it was 8. 1% （125/1549） in Peking University First Hospital, 13.1% （150/1142）, which was the highest （P 〈0. 01 ）, in Peking University Third Hospital, 5.5% （369/6656） in Beijing Gynecological and Obstetric Hospital and 34. 0% （311/5850） in Women＇s and Children＇s Hospital of Haidian District. The preterm birth rate at the two comprehensive hospitals was significantly higher than that of the two specialized hospitals [ 10. 2% （275/2691） vs 5.4% （680/12 506）, P 〈 0. 01 ]. （2） Gestational weeks at delivery ： The incidence of preterm birth before 34 weeks was 28.5% （272/954） and the number changed to 71.5% （682/954）for those preterm deliveries after 34 weeks. However, this number varied among the 4 hospitals. Peking University First Hospital had the highest incidence of preterm birth before 34 weeks （ P 〈 0. 05）, and the lowest was found in Women＇s and Children＇s Hospital of Haidian District（P 〈0. 01 ）, but no difference was found between Peking University Third Hospital and Beijing Gynecological and Obstetric Hospital. （3） Etiology of preterm birth ： Preterm premature rupture of membranes （PPROM） accounted for the most proportion of all preterm birth cases, followed by iatrogenic preterm birth and spontaneous preterm birth. But the causes of preterm birth in the 4 hospitals were different. Peking University Third Hospital had a higher incidence of iatrogenic preterm birth than the others （ P 〈 0.01 ）, and Peking University First Hospital had a higher incidence of preterm birth caused by PPROM and lower incidence of spontaneous preterm birth. The first four reasons of iatrogenic preterm birth were preeclampsia （ 143, 42. 0% ）, fetal distress （58, 17.1% ） , placenta previa （43, 12. 6% ） and placenta abruption （33, 9.7% ）. （4） Neonatal outcomes in different hospitals： The neonatal outcomes were quite different among the 4 hospitals due to different causes and different delivery weeks. The highest neonatal mortality rate was found in Beijing Gynecological and Obstetric Hospital （5.4%, 22/408） compared to that in Women＇s and Children＇s Hospital of Haidian District （ 1.3% ,4/320） and Peking University Third Hospital （0. 6%, 1/170） （ P 〈 0. 01 ）, but without any difference when compared to that in Peking University First Hospital （ 2. 4%, 3/ 124） （P 〉0. 05）. （5） Neonatal outcomes at different gestational age： The recovery rate of preterm infants delivered at 〈 32 weeks was lower than those delivered ≥ 32 weeks （ P 〈 0. 01 ）, and this number rose to 99.6% in those delivered ≥ 34 weeks. More infants delivered 〈 32 weeks were given up for treatment or died during the perinatal period than those delivered ≥ 32 weeks, with the neonatal mortality rate of 22. 1% for those delivered at 〈 32 weeks and only 0. 3% for those delivered at ≥ 34 weeks （ P 〈 0. 01 ）. （6） Neonatal outcomes for various causes ： The premature neonatal mortality rate for iatrogenic preterm births was higher than that of PPROM （4. 9% vs 1.6%, P 〈 0. 05 ）. But the neonatal recovery rates were similar among the PPROM, spontaneous and iatrogenic preterm birth group （P 〉 0. 05）. Conclusions Preterm birth is associated with high perinatal mortality rate, especially for those delivered before 32 weeks which would be highlighted in prevention. Reduction of the iatrogenic preterm birth, combined with proper prevention of PPROM, is an important issue in decreasing the prevalence of preterm birth.