ASSOCIATION OF EARLY BETA-HUMAN CHORIONIC-GONADOTROPIN VALUES WITH PREGNANCY WASTAGE AND MULTIPLE IMPLANTATION IN A DONOR OOCYTE PROGRAM

An early marker predictive of a viable pregnancy would ease the anxiet y associated with positive pregnancy tests after the use of donor oocy tes. We examined the predictive value of an early serum quantitative h uman chorionic gonadotrophin (Q-HCG) concentration on pregnancy outcom e following oocyte donation. Embryo transfers after oocyte donation re sulting in a positive serum beta-HCG were examined beginning 9 days af ter embryo transfer from those samples assayed in our laboratory (n = 77). Q-HCG concentrations were measured in our laboratory by an immuno radiometric assay utilizing the first International Reference Preparat ion. Implantations were defined as the number of gestational sacs visu alized by transvaginal ultrasound 21 days after embryo transfer. Bioch emical pregnancies were those with transient elevations in beta-HCG co ncentration but without implantation sites. Spontaneous abortions were characterized by an implantation site with the eventual arrest of dev elopment. Ongoing/delivered pregnancies developed appropriately and pr oceeded beyond the first trimester. Day 9 Q-HCG concentrations did not differentiate between biochemical pregnancies/ spontaneous abortions and ongoing/delivered pregnancies, although mean +/- SD concentrations for biochemical pregnancies were significantly lower than those for t he other groups (P < 0.0001): biochemical pregnancies, n = 18, 5.8 +/- 8.9 mIU/ml, range 0-35; spontaneous abortions, n = 2, 46.0 +/- 10.0 m IU/ml, range 39-53; ongoing/delivered pregnancies, n = 57, 41.5 +/- 35 .4 mIU/ml, range 0-214. In addition, day 9 Q-HCG concentrations did no t differentiate between multiple implantations, although the implantat ion of four sacs had a significantly higher mean Q-HCG concentration c ompared with the implantation of fewer sacs (P < 0.0001): one sac, n = 22, 32.2 +/- 21.5 mIU/ml, range 3-78; two sacs, n = 25, 35.8 +/- 21.3 , range 0-81; three sacs, n = 7, 47.1 +/- 37.1 mIU/ml, range 22-126; f our sacs, n = 4, 122.3 +/- 62.4 mIU/ml, range 76-214. The positive pre dictive value of a Q-HCG > 10 mIU/ml was 0.91 (sensitivity 91%, specif icity 75%). These initial data suggest that early day 9 serum Q-HCG de terminations do not accurately identify viable pregnancies or multiple implantations. Even an early negative pregnancy test Should be repeat ed because it can be associated with a normal pregnancy.