[Comprehensive clinical study on pathogenesis of early spontaneous abortion]

Clinical studies on the natural history of early spontaneous abortion included ultrasonic examination of the conceptus, determination of serum human chorionic gonadotropin beta (H), evaluation of trophoblast viability (V), chromosomal analysis of chorionic tissue and assessment of the mixed lymphocyte reaction-blocking effect (BE) of serum in 22 cases with missed abortion and 4 with incomplete abortion. TV was evaluated by simultaneous staining with fluorescein diacetate-propidium iodide (FDA-PI). The data obtained were as follows: 1) Chromosomal abnormalities were observed in 13 of 21 patients analyzed. 2) V was 78.6 +/- 5.6 (n = 7) in induced abortion, 42.3 +/- 16.2 (n = 22) in missed abortion and 8.8 +/- 4.8 (n = 4) in incomplete abortion. 3) There was a significant linear correlation between the maximum diameter of the gestational sac (D) and the weight of the chorionic tissue (W) (W = 1.30 + 0.08D, r = 0.44, p less than 0.05), and between the titer of H and the weight of the viable chorionic tissue (Wv = W x V) (Wv = 0.66 + 0.01H, r = 0.77, p less than 0.01). Consequently, the following formula was devised: V = (H + 66)/(0.08D + 1.30). 4) Results obtained from the formula indicated that V stays at an elevated level for some time and then falls gradually or rapidly after fetal death in spontaneous abortion. 5) Spontaneous expulsion of the conceptus occurred when V declined to about 10% in 4 cases. 6) There was a significant linear correlation between BE and V (V = 34.58 + 0.31BE, r = 0.45, p less than 0.05). It was thus concluded that the intrauterine retention period of the conceptus after fetal death is dependent on V, which can be estimated by D, H and BE in spontaneous abortion.