Effects of early pregnancy loss on hormone levels in the subsequent menstrual cycle.

Previous studies of hormone patterns after clinical miscarriage suggest reduced pituitary function. Hormonal effects of very early pregnancy loss (before 6 weeks gestation) have not been described. We used within-woman differences between menstrual cycles in urinary hormone measurements from women in the North Carolina Early Pregnancy Study to describe hormonal changes after very early pregnancy loss (n = 28 early losses; 80 non-conception comparison cycles). We found lower pre-ovulatory luteinising hormone and shorter luteal phase length after very early pregnancy loss, but the differences were non-significant (p > 0.3) and smaller than those reported in the spontaneous miscarriage literature. Consistent with the reduced pituitary function reported post-spontaneous miscarriage, we found a slower rate of oestrogen rise (p = 0.08). There was no evidence of lower mid-luteal steroid levels as has been suggested for post-spontaneous miscarriage cycles. Very early pregnancy losses do not appear to influence subsequent menstrual cycles to the same degree as spontaneous miscarriages.