Cole L A, Isozaki T, Jones E E
Department of Obstetrics and Gynecology, Yale University School of Medicine, New Haven, Conn. 06477, USA.
Fetal Diagn Ther. 1997 Nov-Dec;12(6):336-9. doi: 10.1159/000264500.
The incidence of ectopic pregnancy in the United States has risen 6-fold in the last three decades. It now accounts for about 2% of reported pregnancies. Tests are now needed to identify ectopic pregnancy before it is clinically evident. We evaluated human chorionic gonadotropin beta-core fragment as a test to predict ectopic pregnancy and spontaneous abortion. Urine samples were collected from women with in vitro fertilized pregnancies, 2 1/2-5 weeks after embryo transfer. Fifty samples were collected from those later shown to have normal intrauterine pregnancies, samples from 13 women subsequently found (at 5-9.3 weeks) to have ectopic gestations, and 15 from those with impending spontaneous abortion. Beta-Core fragment levels were determined by immunoassay, and results normalized to creatinine concentration. Median beta-core fragment levels at 2 1/2-3, 3-4, and 4-5 weeks after embryo transfer, were 6.7, 91 and 737 microg/g for unaffected pregnancies, 1.0, 5.9 and 0.6 microg/g for impending ectopic pregnancies (0.15, 0.065 and 0.0008, multiples of the unaffected pregnancy median, MoM), and 0.75, 6.8 and 12 microg/g for impending spontaneous abortions (0.11, 0.07 and 0.016 MoM). A gestation-linked curve was modeled to discriminate unaffected pregnancy from impending ectopic gestation or spontaneous abortion. Plotted beta-core fragment levels were below this curve in 12 of 13 (92%) women with impending ectopic pregnancy, in 10 of 15 (67%) with spontaneous abortion outcome, and in 2 of 50 (4%) with intrauterine pregnancy and term outcome. Measurement of urine beta-core fragment at 2 1/2-5 weeks after embryo transfer (4 1/2-7 weeks after last menstrual period) might be useful for identifying failing pregnancies. Over three quarters (predictive value positive 76%) of those with low beta-core fragment levels have ectopic pregnancy or spontaneous abortion. On the contrary, 95% (predictive value negative) of those with normal range test values may be predicted to have a nonfailing term pregnancy. Diagnosis of ectopic pregnancy could be confirmed by transvaginal ultrasound, and ectopic pregnancy terminated early by nonsurgical methods, with minimal mortality or fertility loss. Major fetal defects that cause spontaneous abort pregnancies may also be recognized by transvaginal ultrasound. In such cases, chorionic villous sampling or possibly termination may be considered.
在过去三十年中，美国宫外孕的发病率增长了6倍。目前，宫外孕约占已报告妊娠的2%。现在需要在临床症状出现之前进行检测以识别宫外孕。我们评估了人绒毛膜促性腺激素β核心片段作为预测宫外孕和自然流产的一项检测指标。从接受体外受精妊娠的女性中收集尿液样本，时间为胚胎移植后2.5至5周。从后来被证实为宫内妊娠正常的女性中收集了50份样本，从随后（在5至9.3周时）被发现为宫外孕的13名女性中收集了样本，以及从有自然流产倾向的女性中收集了15份样本。通过免疫测定法测定β核心片段水平，并将结果根据肌酐浓度进行标准化。胚胎移植后2.5至3周、3至4周以及4至5周时，未受影响妊娠的β核心片段水平中位数分别为6.7、91和737微克/克，宫外孕倾向妊娠的分别为1.0、5.9和0.6微克/克（分别为未受影响妊娠中位数的0.15、0.065和0.0008倍，MoM），自然流产倾向妊娠的分别为0.75、6.8和12微克/克（分别为0.11、0.07和0.016 MoM）。构建了一条与妊娠相关的曲线，以区分未受影响的妊娠与宫外孕倾向或自然流产倾向。在13名有宫外孕倾向的女性中，有12名（92%）的β核心片段水平绘制值低于该曲线；在15名有自然流产结局的女性中，有10名（67%）低于该曲线；在50名有宫内妊娠并足月分娩结局的女性中，有2名（4%）低于该曲线。在胚胎移植后2.5至5周（末次月经后4.5至7周）测量尿液β核心片段，可能有助于识别妊娠失败情况。β核心片段水平低的患者中，超过四分之三（阳性预测值为76%）患有宫外孕或自然流产。相反，检测值在正常范围内的患者中，95%（阴性预测值）预计会有正常的足月妊娠。宫外孕的诊断可通过经阴道超声确认，宫外孕可通过非手术方法早期终止，死亡率和生育能力损失最小。经阴道超声也可识别导致自然流产的主要胎儿缺陷。在这种情况下，可考虑进行绒毛取样或可能的终止妊娠。
