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The purpose of this study is to provide evidence that empty follicle syndrome (EFS) is a result of an abnormality in the in-vivo biological activity of some batches of commercially available human chorionic gonadotrophin (HCG). This is a comparative study between six consecutive in-vitro fertilization (IVF) cases with EFS (study group) and 10 IVF pregnancy cycles (control group). Both groups received the same ovarian stimulation protocol consisting of leuprolide acetate and human menopausal gonadotrophin (HMG). An i.m. injection of 10,000 IU of HCG was administered once follicles had reached 18-20 mm and oestradiol/follicle > or = 16 mm was at least 900 pmol/l. Transvaginal aspiration was performed 36 h later. Plasma HCG prior to and 12 h after i.m. injection as well as the follicular fluid (FF) concentrations of oestradiol, progesterone, luteinizing hormone (LH) and HCG were determined in the study group and controls. The in-vitro biological activity of the batch of HCG used by the EFS cases and the control group was determined using a Leydig cell preparation from adult rats. Furthermore, the plasma clearance rate after i.v. injection of 5000 IU of HCG, from the same batches, was studied in three male volunteers. In the IVF cycles, no HCG was detected in plasma prior to the injection of commercial HCG. After 12 h, no HCG was detected in the study group compared to a mean of 207.5 IU/l (110-360) in controls. Mean FF concentration of LH, HCG, progesterone and oestradiol was 0.9 IU/l, 0 IU/l, 3.1 nmol/ml and 4.4 nmol/ml in EFS compared to 1.0, 98.3, 32.0 and 3.7 in pregnancy cycles. The in-vitro biological activity in both HCG batches was not significantly different; however, immunoreactive HCG used in EFS cases was undetectable in plasma of male volunteers as soon as 10 min after i.v. injection of 5000 IU of HCG. The endocrine abnormalities found in follicular fluids of EFS are not a consequence of an ovarian problem but the result of a lack of exposure to biologically active HCG. The rapid clearance of the drug after i.v. injection and the high affinity of desialylated HCG to liver cells suggest this to be a possible explanation for this infrequent but unfortunate event.

The high correlation between bleeding disturbances and the presence of a pouch, in the absence of other pathologic entities, suggests this anatomic defect as the possible cause, especially in view of the fact that women who had heavier and longer bleeding episodes tended to have a larger pouch. Transvaginal sonography is a very simple, noninvasive, low-cost examination that should be considered as the first choice for screening, because it highly correlates (100%) with hysteroscopy in the diagnosis of this defect and may help rule out other causes.

This prospective study analyses the value of the beta-subunit of human chorionic gonadotrophin (beta-HCG) in 120 pregnancies obtained after in-vitro fertilization (IVF)--embryo transfer. Spontaneous conception cycles (n = 16) were also analysed allowing a comparison between these two forms of conception. Of the 120 clinical pregnancies, 48 started as single gestations and 50 started with two or more sacs. There were 14 clinical abortions and eight ectopic pregnancies. All subjects had blood samples taken under a fixed protocol on days 11, 14, 17, 20 and 23 after follicular aspiration. Weekly samples were obtained thereafter until day 60 from ovum retrieval. Transvaginal ultrasounds were performed at weekly intervals, starting on day 23 after follicular aspiration. In spontaneous conception cycles blood samples were obtained daily, starting on the day of follicular rupture. In spontaneous conception cycles and in IVF-embryo transfer conceptions, the doubling time (DT) of beta-HCG was 1.4 +/- 0.3 and 1.6 +/- 0.4 days respectively. This difference was not significant. In multigestations, the DT was 1.5 +/- 0.3 days. The absolute values of beta-HCG in early spontaneous gestations were significantly higher than in IVF-embryo transfer cycles, suggesting that the blastocyst implants with less cellular mass when initiated in vitro as compared with the in-vivo condition. The early prediction of ectopic pregnancy and spontaneous clinical abortion was analysed by the beta-HCG profile as well as the absolute values in comparison to normal pregnancies. Both parameters showed significant differences as early as the interval between days 11 and 23 from follicular aspiration.(ABSTRACT TRUNCATED AT 250 WORDS)

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