Endocrinology of luteal phase defects, habitual abortion and trophoblastic-luteal complex during normal and embryopathic gestation

Progesterone production by the corpus luteum is essential for the normal maintenance of early pregnancy. After the production of progesterone is transferred to the placenta during the first trimester (the luteo-placental shift), the corpus luteum becomes dispensable (Csapo et al., 1972; Csapo and Pullkinen, 1978). Clinical sequelae of disordered progesterone production by the corpus luteum (the luteal phase defect) include infertility and habitual abortion (three consecutive spontaneous losses). The prevalence of luteal defects in infertility patients was 33% in Sydney, Australia (Grant,1976); 3.5 in Baltimore (Jones,1976); 8.1% in Farmington, Connecticut (Rosenberg et al., 1980); and 19% in Memphis, Tennessee (Wentz, 1980). In habitually aborting women, the incidence of luteal defects was 64% in Sydney (Grant, 1976), 35 in Baltimore (Jones, 1976), and 38% in Madrid (Botella Llusia, 1962). To a varying extent, patient selection and differing diagnostic criteria accounted for the range in prevalence noted. Since the statistical distribution of luteal phase defects in the normal fertile population has not been compared to that of habitually aborting women, the clinical relevance of luteal phase defects in the pathogenesis of habitual abortion was considered uncertain (Glass and Golbus, 1978). Furthermore, the efficacy of treatment on the outcome of pregnancy in habitually aborting women has not as yet been assessed in stringently controlled clinical trials. While the validity of these concerns is not in doubt, published research data from several countries, and current knowledge of the important role of the corpus luteum in the maintenance of pregnancy during the first trimester in women (Csapo et al., 1972; Csapo and Pullkinen, 1978; Hammerstein, 1974) and in primates (Bosu and Johansson, 1975) illustrate the clinical importance of the luteal defect.