Luteal function associated with single, multiple and ectopic embryo implantation in natural cycles or after ovarian hyperstimulation for in-vitro fertilization/gamete intra-fallopian transfer.

Levels of reproductive steroids and gonadotrophins were analysed retrospectively during the peri-implantation period following non-conceptional and conceptional natural cycles and in cycles associated with ovarian hyperstimulation for in-vitro fertilization or gamete intra-Fallopian transfer. In cycles not associated with conception, the luteal phase of hyperstimulated cycles (n = 100) was characterized by higher serum progesterone and oestradiol levels (P less than 0.01) and with an earlier decline in steroids than in natural cycles (n = 21). On day 11 (day of oocyte recovery = day 0), the level of progesterone in twin (n = 59) and triplet (n = 13) pregnancies was higher than singleton pregnancies (n = 176) (P less than 0.006, P less than 0.006 respectively) while those destined to abort (n = 66) had lower progesterone levels (P less than 0.01). Ectopic implantation (n = 11) had the lowest progesterone concentrations on day 11 (P less than 0.01) and this may imply a delay in corpus luteum rescue or a later implantation time than intrauterine conception.