The changing pattern of uterine contractions before and after fresh embryo transfer and its relation to clinical outcome

Abstract

In this prospective cohort study of 286 women undergoing fresh embryo transfer after IVF, uterine contraction frequency and direction were measured before (-5 min), 5 min after (+5 min) and 60 min after (+60 min) embryo transfer. Mean ± SD uterine contraction frequency at -5 min was 1.8 ± 1.1 contractions per min, increasing significantly (P < 0.05) to 2.0 ± 1.1 at +5 min, and returning back to baseline 1.8 ± 1.1 at +60 min. At -5 min, the proportion of women the with retrograde, antegrade, indeterminate direction and absent contractions were 33%, 44%, 17% and 6%; at +5 min, 40%, 42%, 13% and 5%, and at +60 min, 42%, 38%, 14% and 6%. No significant change was observed in the proportion of direction at these three time points. Logistic regression analysis showed live birth rate was significantly reduced in older women (P = 0.035) and in those with higher uterine contraction frequency at +5 min (P = 0.006). Frequency of uterine contraction immediately after embryo transfer (+5 min) seemed to be a significant predictor of IVF outcome and may help to identify women who could benefit from the use of muscle relaxant therapy to improve outcome.

Keywords: contraction direction; contraction frequency; embryo transfer; pregnancy rate; uterine contractions.