Amniotic fluid accumulation in the first trimester.

Amniotic fluid volume was estimated sonographically in 507 of 977 first trimester pregnancies with living fetuses and in 99 of 227 instances of missed abortion. Volume is correlated with fetal length, cross referenced by average heart rate for living fetuses. Fluid volume increases exponentially after 9 weeks, consistent with the onset of renal function.

Immunologic aspects of IUD action.

Embryo implantation has been demonstrated to depend on specific lymphocyte populations within the uterine cavity. Intrauterine devices (IUD) exert their contraceptive action by prevention of embryo implantation via presently still unknown mechanisms. Therefore, mononuclear cell populations from mice uteri which either contained silastic or copper (Cu) IUD fragments or were sham-operated were evaluated, utilizing monoclonal antibodies against specific cell markers.

Comparison of human chorionic gonadotropin measurements by radioimmunoassay and in vitro bioassay.

A sensitive, accurate, and reproducible in vitro bioassay was developed for measuring human chorionic gonadotropin (hCG), based on testosterone production by collagenase-dispersed interstitial cells of rat testes in response to hCG. The results were compared to those obtained by established beta hCG radioimmunoassay. The assay sensitivity was 25 pg hCG-CR119/ml (65 microIU second IRP/ml).