UTERINE CONTRACTIONS AT THE TIME OF EMBRYO-TRANSFER - A HINDRANCE TO IMPLANTATION

Objectifs : To investigate the hormonal control and the possible conse quences of uterine contractions (UC) on IVF-ET outcome. Materials and Methods : We studied prospectively 220 controlled ovarian hyperstimula tion (COH) cycles for IVF-ET: Just before ET; women underwent 5-minute digital recordings of the uterus using US image analysis software for UC assessment. Plasma progesterone (P) and estradiol were measured. F our groups were defined according to UC frequency :less than or equal to 3.0 (n = 53), 3.1 to 4.0 (n = 50), 4.1 to 5.0 (n = 43), and > 5.0 ( n = 74) UC/minute, respectively. Results : Patients, COH and embryolog y characteristics were comparable in all groups. Notwithsanding estrad iol levels were not associated with UC characteristics, plasma P and U C frequency were negatively correlated (r = -0.34, P < 0.001). A stepw ise decrease in clinical and ongoing pregnancy as well as implantation rates occurred from the lowest to the highest UC frequency groups (53 %, 36 %, 21 %; 46 %, 32 %, 20 %; 23 %, 19 %, 10 %; and 14 %, 11 %, 4 %; P < 0.001). Direction of UC did not affect ET outcome. Conclusions : The negative correlation between UC frequency and P levels supports the utero-relaxing properties of P. High frequency UC on the day of ET hinder IVF-ET outcome, possibly by expelling embryos out of the uteri ne cavity.