Uterine contractions at the time of embryo transfer alter pregnancy rates after in-vitro fertilization

Hum Reprod. 1998 Jul;13(7):1968-74. doi: 10.1093/humrep/13.7.1968.


To investigate the possible consequences of uterine contractions (UC) as visualized by ultrasound (US) on in-vitro fertilization (IVF)-embryo transfer outcome, we studied prospectively 209 infertile women undergoing 220 cycles of controlled ovarian stimulation. Inclusion criteria were age < or = 38 years, a morphologically normal uterus, and at least three good quality embryos transferred. Just before embryo transfer, women underwent 5 min digital recordings of the uterus using US image analysis software for UC assessment. Plasma progesterone and oestradiol concentrations were measured. Four groups were defined according to UC frequency: < or = 3.0 (n = 53), 3.1-4.0 (n = 50), 4.1-5.0 (n = 43), and > 5.0 (n = 74) UC/min respectively. Patients, controlled ovarian hyperstimulation and embryology characteristics were comparable in all groups. A stepwise decrease in clinical and ongoing pregnancy rates as well as in 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). Plasma progesterone and UC frequency were negatively correlated (r = -0.34, P < 0.001). Direction of UC did not affect embryo transfer outcome. As this study was controlled strictly for confounding variables and UC were assessed objectively by a computerized system, its results indicate that high frequency UC on the day of embryo transfer hinder IVF-embryo transfer outcome, possibly by expelling embryos out of the uterine cavity. The negative correlation between UC frequency and progesterone concentrations supports the uterine relaxing properties of progesterone.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chorionic Gonadotropin / administration & dosage
  • Embryo Transfer*
  • Estradiol / blood
  • Female
  • Fertilization in Vitro*
  • Follicle Stimulating Hormone / blood
  • Humans
  • Menotropins / administration & dosage
  • Ovulation Induction
  • Pregnancy
  • Progesterone / blood
  • Prospective Studies
  • Ultrasonography
  • Uterine Contraction*
  • Uterus / diagnostic imaging


  • Chorionic Gonadotropin
  • Progesterone
  • Estradiol
  • Menotropins
  • Follicle Stimulating Hormone