Rapid measurement of urinary pregnanediol glucuronide to diagnose ectopic pregnancy

Spontaneous miscarriage in first trimester pregnancy is associated with altered urinary metabolite profile

Threatened miscarriage is the most common gynecological emergency, occurring in about 20% of pregnant women. Approximately one in four of these patients go on to have spontaneous miscarriage and the etiology of miscarriage still remains elusive. In a bid to identify possible biomarkers and novel treatment targets, many studies have been undertaken to elucidate the pathways that lead to a miscarriage. Luteal phase deficiency has been shown to contribute to miscarriages, and the measurement of serum progesterone as a prognostic marker and the prescription of progesterone supplementation has been proposed as possible diagnostic and treatment methods. However, luteal phase deficiency only accounts for 35% of miscarriages. In order to understand the other causes of spontaneous miscarriage and possible novel urine biomarkers for miscarriage, we looked at the changes in urinary metabolites in women with threatened miscarriage. To this end, we performed a case-control study of eighty patients who presented with threatened miscarriage between 6 and 10 weeks gestation. Urine metabolomics analyses of forty patients with spontaneous miscarriages and forty patients with ongoing pregnancies at 16 weeks gestation point to an impaired placental mitochondrial β-oxidation of fatty acids as the possible cause of spontaneous miscarriage. This study also highlighted the potential of urine metabolites as a non-invasive screening tool for the risk stratification of women presenting with threatened miscarriage.

Ectopic pregnancy from surgical emergency to medical management

During the past 25 years, the incidence of ectopic pregnancy has progressively increased while the morbidity and mortality have substantially decreased, and the treatment has progressed from salpingectomy by laparotomy to conservative surgery by laparoscopy and more recently to medical therapy. This therapeutic transition from surgical emergency to medical management has been attributed to early diagnosis through the use of sensitive assays for hCG and the high definition of vaginal ultrasound. By using these sensitive diagnostic tools, we are now able to select those patients who are most likely to respond to medical management versus those who are at high risk of rupture and require surgery. Besides being less invasive and associated with significantly lower risks, medical therapy with methotrexate results in significant cost savings, which have been calculated to be approximately $3,000 per treated patient. Our goal is to identify those patients with ectopic pregnancy who are most likely to respond to methotrexate therapy and least likely to develop significant side effects. Recent studies have helped us define the predictors of success with methotrexate treatment in women with ectopic pregnancy. The reported success rates of treating ectopic pregnancy with methotrexate vary from 71% to 100%. The highest success rates have been reported from institutions that have detailed diagnostic and therapeutic protocols, readily available assays for serum hCG levels, high-resolution vaginal probe ultrasound, and support staff that can closely monitor clinical response. The importance of developing specific protocols to create a clinical environment that supports the effective use of medical therapy for ectopic pregnancy is confirmed by the associated cost savings, decreased morbidity, and patient preference. Modern diagnostic advances and minimally invasive treatments coupled with improved success rates for assisted reproductive technologies should reduce the morbidity and mortality associated with ectopic pregnancy and offer the affected couple a much more optimistic outlook for subsequent reproductive potential.

Serum progesterone and endovaginal sonography by emergency physicians in the evaluation of ectopic pregnancy

OBJECTIVE

To determine a discriminatory level for serum progesterone (SP) in pregnant patients with no definite intrauterine pregnancy (IUP) on endovaginal ultrasonography (US) in the differentiation of ectopic pregnancy from normal IUPs.

METHODS

A prospective observational study in a convenience sample of women at risk for ectopic pregnancy was performed at an urban teaching hospital from May 1991 until May 1994. Women aged > or =18 years presenting to the ED with a positive pregnancy test in combination with pelvic or abdominal pain, vaginal bleeding, orthostasis, adnexal mass or tenderness, or any historical risk factor for ectopic pregnancy were eligible. Hypotensive or unstable patients were excluded. Endovaginal US was performed and patients with no definite IUP had a serum beta-hCG and SP measured.

RESULTS

314 patients were enrolled, with 14 excluded for lack of follow-up or incomplete SP data, yielding 300 patients. The initial endovaginal US diagnoses included 169 definite IUP, 31 abnormal IUP, 5 definite ectopic pregnancy, and 95 no definite IUP. 68/95 had SP measured, with values of 22.8 +/- 13.4 ng/mL (mean +/- SD) for IUP; 4.9 +/- 6.5 for spontaneous abortion, and 7.5 +/- 7.2 for ectopic pregnancy. The mean values were significantly different (2-tailed t-test) for ectopic pregnancy vs IUP and for spontaneous abortion vs IUP. An SP of > or =11 ng/mL (sensitivity 91%; specificity 84%) was post hoc the best cutoff value for suggesting an IUP when the endovaginal US was not definite for IUP.

CONCLUSIONS

SP cannot reliably discriminate ectopic pregnancy vs spontaneous abortion in pregnant patients with no definite IUP on endovaginal US; however, a low SP (<11 ng/mL) in this sonographic category suggests an abnormal pregnancy.

Does creatinine adjustment of urinary pregnanediol glucuronide reduce or introduce measurement error?

Correlation between urinary pregnanediol and serum progesterone measurements and the influence of age, race, smoking and urinary creatinine adjustment was determined during the luteal phase of the menstrual cycle in 175 volunteers. A decline in serum progesterone was observed with increasing age. Mean baseline urinary creatinine declined with increasing age in non-smokers and was not affected by race or baseline weight. An excellent correlation between urinary pregnanediol glucuronide and serum progesterone levels existed except when urinary pregnanediol concentrations were adjusted using creatinine measurements in older individuals. Adjustment of urinary pregnanediol glucuronide concentration using creatinine measurement is therefore discouraged.

Utility and predictive value of a rapid measurement of urinary pregnanediol glucuronide by enzyme immunoassay in an infertility practice

STUDY OBJECTIVE

To assess the clinical utility of measuring urinary pregnanediol glucuronide in random samples in an infertility practice.

DESIGN

Samples of urine were collected from patients approximately 3 weeks from their last menstrual period to ascertain if ovulation had occurred. Each sample was tested for specific gravity before analyzing for pregnanediol glucuronide. Simultaneous venipuncture was performed to compare results from the urinary assay to quantitative measures of serum progesterone (P).

SETTING

All patients were randomly sampled.

PATIENTS

Three hundred ninety women undergoing pituitary down regulation with leuprolide acetate were chosen for study because they routinely initiate medication after documentation of ovulation.

OUTCOME MEASURES

The performance of the urinary pregnanediol glucuronide was evaluated as to its sensitivity, specificity, predictive value, and test efficiency compared with a serum measurement of 2.5 ng/mL and 10.0 ng/mL.

RESULTS

The performance characteristics of the pregnanediol glucuronide assay were directly related to the hydration status of the patient at the time of sample collection. Regardless of urine specific gravity, if pregnanediol glucuronide was qualitatively detected (greater than 3 micrograms/mL), serum P was greater than 2.5 ng/mL. However, in cases in which pregnanediol glucuronide was undetected (less than 3 micrograms/mL), results were only accurate when the specific gravity was greater than or equal to 1.020. When comparing urinary pregnanediol glucuronide values to serum greater than 10 ng/mL, both specificity and predictive value of a positive test decreased because of increased numbers of false-positive results.

CONCLUSIONS

The enzyme immunoassay measurement for pregnanediol glucuronide may replace the use of serum P in documenting the ovulatory status of many patients. However, all specimens must be checked for specific gravity and if less than 1.020, a serum P should be used to ensure accuracy.

Effect of hydration on random levels of urinary pregnanediol glucuronide

To determine the effect hydration has upon the relationship between serum progesterone and its urinary metabolite pregnanediol-3 alpha-glucuronide (PDG) we measured spot samples from patients (n = 207) presenting in the 1st trimester of pregnancy. Serum and urine specimens were obtained simultaneously and measured for progesterone and PDG by radioimmunoassay (RIA). Urine specific gravity was also measured at the time of sample collection. Results demonstrated that in samples where the urine specific gravity was greater than or equal to 1.015 there was a strong positive correlation between serum progesterone and PDG (r greater than 0.60, p less than 0.001). However, when urine samples were below a specific gravity of 1.015, serum and urinary steroid values correlated poorly or not at all. We conclude that the measurement of specific gravity should be routinely performed when determining random values of urinary PDG, since only samples in which the urine is adequately concentrated accurately reflect corresponding serum progesterone concentrations.

Reevaluation of the role of culdocentesis in the management of ectopic pregnancy

Culdocentesis has been used routinely in the evaluation of ectopic pregnancy. To determine whether culdocentesis continues to play an important role, we reviewed the operative findings of 297 women undergoing an operative procedure because of ectopic pregnancy. Culdocentesis was performed before surgery in 252 cases. Of those, 210 (83%) had positive test results and 42 (17%) had negative results. Positive results accurately predicted a ruptured ectopic pregnancy in 50% of cases, whereas negative test results were predictive of an unruptured ectopic pregnancy in 58% of cases. Six patients without an ectopic pregnancy underwent unnecessary laparotomy because of positive culdocentesis test results, whereas 27 patients who were discharged from the emergency room after negative test results were obtained subsequently were found to have ectopic pregnancies. The results of this study imply that culdocentesis is of limited value in a clinical setting in which sensitive and rapid testing and pelvic ultrasonography are used.

Spontaneously resorbing ectopic pregnancy: preservation of human chorionic gonadotropin bioactivity despite declining steroid hormone levels

We compared serum hormone profiles of patients with normal intrauterine pregnancies (n = 14), spontaneously resorbing ectopic pregnancies (n = 10), and viable ectopic pregnancies (n = 26). Hormone profiles were evaluated at 5 to 8 weeks' gestational age. Ectopic pregnancies were diagnosed by laparoscopy; intrauterine gestations were confirmed by ultrasonography. Immunoreactive beta-human chorionic gonadotropin, progesterone, estradiol, and 17-hydroxyprogesterone were measured by radioimmunoassay. Bioactive human chorionic gonadotropin was measured by a modified mouse Leydig cell bioassay. Diminished steroid production was noted in ectopic pregnancies; levels in serum of patients with resorbing ectopic pregnancies were lower than values expressed in viable ectopic pregnancies (p less than 0.01). Serum levels of human chorionic gonadotropin bioactivity correlated closely with immunoreactive human chorionic gonadotropin in all three groups (r = 0.81, p less than 0.01). Ratios of bioactive human chorionic gonadotropin to immunoreactive beta-human chorionic gonadotropin were similar (0.93 +/- 0.26 in resorbing ectopic pregnancies, 1.11 +/- 0.16 in viable ectopic pregnancies, and 0.90 +/- 0.10 in intrauterine pregnancies). We conclude that although reduced serum levels of steroids noted in ectopic pregnancy suggest an impairment in corpus luteum activity, diminished steroid production was not attributable to lower human chorionic gonadotropin bioactivity.