Allanson Ben, Jennings Belinda, Jacques Angela, Charles Adrian K, Keil Anthony D, Dickinson Jan E
School of Women's and Infants' Health, The University of Western Australia, Perth, Western Australia, Australia.
Aust N Z J Obstet Gynaecol. 2010 Jun;50(3):221-5. doi: 10.1111/j.1479-828X.2010.01148.x.
Chorioamnionitis is a common cause of second trimester pregnancy loss, usually due to ascending infection. This study investigates the prevalence and bacteriology of chorioamnionitis in cases of spontaneous pregnancy loss in previable gestations (16-22 weeks).
Fetal losses between 16- and 22-week gestation were identified from the institutional database over a three-year period. Cases with an autopsy were identified, pathology reports reviewed, and maternal features noted (clinical symptoms, blood count and vaginal culture results). Second trimester medical termination for fetal abnormality during the same time period served as controls for the confounding influence of labour.
A total of 101 cases of spontaneous non-anomalous non-macerated fetal losses and 103 control cases of induced loss for fetal anomaly were identified. Median gestation of cases was 19 weeks (interquartile range (IQR) 17, 21) and of controls was 20 weeks (IQR 19, 21). Maternal white cell count was higher in cases (median 13.6 IQR 10.8, 16.6) than in controls (9.9 IQR 7.6, 11.5) (P < 0.01). Seventy-eight (77.2%) of 101 cases and no controls had histological chorioamnionitis. A fetal reaction was identified in 48.7% of cases with chorioamnionitis, and the frequency of fetal reaction increased as gestation advanced (5.3% at 16-week gestation vs 33.3% at 22-week gestation). In cases with chorioamnionitis 36/76 (47.4%) were culture positive, whereas 4/25 (16%) without chorioamnionitis were culture positive.
In otherwise normal fetuses, chorioamnionitis is a common finding in mid-trimester pregnancy loss. Routine culture methods have a low sensitivity for isolation of the causative micro-organisms. This inflammatory process seems to predate the onset of labour and appears a primary mechanism in the aetiology of such losses.
绒毛膜羊膜炎是孕中期流产的常见原因，通常由上行感染引起。本研究调查了孕龄前（16 - 22周）自然流产病例中绒毛膜羊膜炎的患病率及细菌学情况。
从机构数据库中识别出孕16至22周的胎儿丢失病例，为期三年。确定有尸检的病例，查阅病理报告，并记录母体特征（临床症状、血常规及阴道培养结果）。同期因胎儿异常而行的孕中期人工流产作为分娩混杂影响的对照。
共识别出101例自然发生的非畸形、非浸软胎儿丢失病例以及103例因胎儿畸形而行人工流产的对照病例。病例的中位孕周为19周（四分位间距（IQR）17, 21），对照的中位孕周为20周（IQR 19, 21）。病例组母体白细胞计数（中位数13.6，IQR 10.8, 16.6）高于对照组（9.9，IQR 7.6, 11.5）（P < 0.01）。101例病例中有78例（77.2%）存在组织学绒毛膜羊膜炎，而对照组无此情况。在绒毛膜羊膜炎病例中，48.7%发现有胎儿反应，且胎儿反应的频率随孕周增加而升高（孕16周时为5.3%，孕22周时为33.3%）。在有绒毛膜羊膜炎的病例中，36/76（47.4%）培养阳性，而无绒毛膜羊膜炎的25例中有4例（16%）培养阳性。
在其他方面正常的胎儿中，绒毛膜羊膜炎是孕中期流产的常见发现。常规培养方法分离致病微生物的敏感性较低。这种炎症过程似乎早于分娩开始，并且似乎是此类流产病因学中的主要机制。
