The human chorionic gonadotropin (hCG) ratio of hemoperitoneum to venous serum (RP/V) has been demonstrated to improve early diagnosis of ectopic pregnancy, according to a study published in the recent online issue of the journal Fertility and Sterility.
YuDong Wang, from the Department of Obstetrics and Gynecology, Shanghai Jiaotong University, Shanghai, China, and colleagues, conducted a retrospective clinical study to determine the value of HCG ratio in the early diagnostic and prognostic assessment of ectopic pregnancy. Venous serum and peritoneal serum samples were taken from 103 subjects who underwent laparoscopy or laparotomy with hemoperitoneum and positive urine hCG tests. Dilatation and curettage was performed on 28 patients, with all patients undergoing ultrasound examination.
Investigators observed that the RP/V was higher in ectopic pregnant subjects (median 4.07) than in patients with hemoperitoneum and intrauterine pregnancy (hIUP; median 0.6), with 1.0 as their suggested threshold value for differential diagnosis. Additionally, when the venous serum HCG level was >1,500 U/L among ectopic pregnancies, a significant difference in the RP/V value was observed in patients with active bleeding (8.03±3.29; n=24) versus patients without active bleeding (4.59±3.88; n=16). Based on the study findings, the researchers concluded that ectopic pregnancy can be instantaneously diagnosed and differentiated from hIUP with the help of RP/V value.
Predanic M (Fertility and Sterility, 2000) conducted a retrospective cohort study to analyze the effect of serum cancer antigen 125 (CA-125) and serial beta-HCG levels for differentiating tubal abortion from viable ectopic pregnancy. The study comprised of 26 women with 7-12 weeks of ectopic pregnancy. Five patients had tubal abortions, verified by laparoscopy, and 21 had active, viable ectopic pregnancies. Three patients from the latter group were administered with methotrexate single dose, while the remaining were managed by surgery. Laparoscopy or laparotomy was conducted to surgically remove the ectopic pregnancies, and medical treatment of the disease was carried out in the subjects. Tubal abortion and viable ectopic pregnancies were distinguished based on the serum CA-125 and β-HCG levels.
The researchers observed a statistically insignificant inverse relation between the levels of CA-125 and β-HCG on linear regression analysis. The mean value of CA-125 and β-HCG levels in patients with tubal abortion were 112.2±11.9 IU/mL and 3,643±3,718 IU/L, respectively; and the corresponding mean values in patients with viable ectopic pregnancy were 30.1±15.3 IU/mL and 10,755±11,465 IU/L for CA-125 and β-HCG, respectively. The study results demonstrated that CA-125 levels, used as an adjunct to serial β-HCG levels, could differentiate tubal abortion from viable ectopic pregnancy.
Ectopic pregnancy or pregnancy outside the uterus, especially within the fallopian tubes, usually occurs due to a physical blockage in the tube that inhibits or retards the movement of fertilized egg. It occurs in one in every 40-100 pregnancies, with early stages similar to other abdominal and gynecological conditions. It can be misdiagnosed as a dysfunctional uterine bleeding, pelvic inflammatory disorder, intrauterine pregnancy, a ruptured corpus luteal cyst, and threatened or incomplete abortion.
Currently, tests such as culdocentesis, hematocrit, quantitative HCG blood test, white blood count, pregnancy tests, and ultrasound are used to diagnose an ectopic pregnancy. Serial beta-HCG levels aid in interpreting the results of ultrasound screening, with a normal pregnancy demonstrating higher levels of HCG as compared to ectopic pregnancy. Other tests, like dilatation and curettage, laparoscopy and laparotomy, help in the confirmation of the diagnosis.
The improved early diagnosis of ectopic pregnancies through human chorionic gonadotropin ratio of peritoneal to venous serum might be helpful in avoiding misdiagnosis of the condition, and providing appropriate timely medical attention.
References
1. Wang Y, Zhao H, Teng Y, Lu L, Tong J. Human chorionic gonadotropin ratio of hemoperitoneum versus venous serum improves early diagnosis of ectopic pregnancy. Fertil Steril. 2008 Nov 29. [Epub ahead of print]
2. Predanic M. Differentiating tubal abortion from viable ectopic pregnancy with serum CA-125 and beta-human chorionic gonadotropin determinations. Fertil Steril. 2000 Mar;73(3):522-5.
3. Lawlor HK, Rubin BJ. Early diagnosis of ectopic pregnancy. West J Med. 1993 August;159(2):195–199.
