Random urinary pregnanediol glucuronide measurements in pregnancy: lack of utility for evaluation of first-trimester vaginal bleeding.

Progesterone and its urinary metabolite pregnanediol-3 alpha-glucuronide (PDG) are generally lower in women with abnormal pregnancies compared to those with normal intrauterine gestations. We evaluated the ability of random urinary PDG measurements determined by enzyme immunoassay (EIA) to differentiate normal from abnormal pregnancies. Patients with first-trimester vaginal bleeding (n = 104) were evaluated. Eventual outcomes indicated 39 women had viable intrauterine pregnancies (IUPs), 54 had spontaneous abortions (SABs) and 11 had ectopic pregnancies (EPs). Urinary PDG was significantly lower in SAB and EP compared to IUP patients. However, a wide range of values in IUP patients was noted (3.2-93.3 micrograms/ml), due to varying degrees of patient hydration at presentation. Hence, random measures of urinary PDG demonstrated poor specificity (32.8%) in correctly differentiating normal from abnormal gestations, thus limiting its clinical usefulness.