According to a study of more than 2,900 patients, endometrium development may plan a more important part in the success of intrauterine insemination than doctors think. The study, completed by researchers from Shady Grove Fertility Reproductive Science Center and Eunice Kennedy Shriver National Institute of Health and Human Development, was published in the journal Fertility and Sterility.

Data were collected from 2,929 patients receiving fertility care between 2004 and 2011. All patients were undergoing treatment (first intrauterine insemination) for infertility of no known explanation. Patients were younger than 43 at the time of treatment.

A total of 466 of 2,929 patients achieved pregnancy. Pregnancy rates improved concurrently with increased endometrial thickness when hCG was administered. Serum E2 levels also played an important part in clinical pregnancy rates with increased levels equating to increased likelihood of clinical pregnancy. Age, follicle number and BMI did not appear to play a part in pregnancy rates.

Source: Wolff EF, Vahidi N, Alford C, Richter K, Widra E. Influences on endometrial development during intrauterine insemination: clinical experience of 2,929 patients with unexplained infertility. Fertil Steril. 2013 Apr 8. pii: S0015-0282(13)00424-X. doi: 10.1016/j.fertnstert.2013.03.023.