Uterine contractility decreases at the time of blastocyst transfers.

High-frequency uterine contractions at the time of non-cavitating embryo transfer influence adversely IVF-embryo transfer outcome. This prompted us to quantify prospectively the possible decline in uterine contraction frequency occurring during later stages of the luteal phase of ovarian stimulation, up to the time of blastocyst transfers, in 43 IVF-embryo transfer candidates. Contractility was assessed on the day of human chorionic gonadotrophin (HCG) administration, 4 days after HCG (non-cavitating embryo transfer; HCG + 4), and 7 days after HCG (blastocyst transfers; HCG + 7). For this, 2 min sagittal uterine scans were obtained by ultrasound and digitized with a computerized system for the assessment of uterine contraction frequency. Our results indicated that a slight, yet significant, decrease in uterine contraction frequency, observed from the day of HCG (4.4 +/- 0.2 contractions/min) to HCG + 4 (3.5 + 0.2 contractions/min), was followed by a more pronounced, additional decrease between HCG + 4 and HCG + 7 (1.5 +/- 0.2 contractions/min; P < 0.001). In conclusion, during the luteal phase of ovarian stimulation, uterine contractility decreases progressively, and reaches a nearly quiescent status 7 days after HCG administration, at the time of blastocyst transfers. It is possible that such a uterine relaxation assists blastocyst implantation.

[1]  J S Abramowicz,et al.  Uterine endometrial peristalsis--a transvaginal ultrasound study. , 1990, Fertility and sterility.

[2]  B. Behr,et al.  Two-blastocyst transfer has similar pregnancy rates and a decreased multiple gestation rate compared with three-blastocyst transfer. , 1999, Fertility and sterility.

[3]  D. Gardner,et al.  Blastocyst culture and transfer: analysis of results and parameters affecting outcome in two in vitro fertilization programs. , 1999, Fertility and sterility.

[4]  G. Ballard,et al.  Characterization of subendometrial myometrial contractions throughout the menstrual cycle in normal fertile women , 1992 .

[5]  M. Eijkemans,et al.  Implantation rates after in vitro fertilization and transfer of a maximum of two embryos that have undergone three to five days of culture. , 2000, Fertility and sterility.

[6]  H. Croxatto,et al.  Studies on the duration of egg transport by the human oviduct. II. Ovum location at various intervals following luteinizing hormone peak. , 1978, American journal of obstetrics and gynecology.

[7]  C. Flamigni,et al.  Uterine contractility during the menstrual cycle. , 2000, Human reproduction.

[8]  J L Evers,et al.  Endometrial wave direction switch and the outcome of in vitro fertilization. , 1999, Fertility and sterility.

[9]  D. Gardner,et al.  Culture and transfer of human blastocysts increases implantation rates and reduces the need for multiple embryo transfers. , 1998, Fertility and sterility.

[10]  M Martinez-Gaudio,et al.  Propagated and nonpropagated myometrial contractions in normal menstrual cycles. , 1973, American journal of obstetrics and gynecology.

[11]  J. M. Bradshaw,et al.  Myometrial activity and the distribution of blastocysts in the uterus of the rat: interference by relaxin. , 1980, Biology of reproduction.

[12]  R. Fanchin,et al.  Uterine contractions at the time of embryo transfer alter pregnancy rates after in-vitro fertilization. , 1998, Human reproduction.

[13]  A. Veiga,et al.  Improved methods for blastocyst formation and culture. , 1998, Human reproduction.

[14]  A. Maclennan,et al.  Effects of relaxin on the intrauterine distribution and antimesometrial positioning and orientation of rat blastocysts before implantation. , 1983, Journal of reproduction and fertility.

[15]  J. Henry,et al.  The contractions of the human uterus during the menstrual cycle , 1943 .

[16]  S Kikuchi,et al.  [A study on the endometrial movement and serum hormonal level in connection with uterine contraction]. , 1990, Nihon Sanka Fujinka Gakkai zasshi.