Since the first successful live birth after in vitro fertilization (IVF) was reported in 1978, more than 5 million children have been born with the help of this and intracytoplasmic sperm injection (ICSI) procedures. However, only approximately 25% to 30% of cycles of IVF and ICSI lead to the birth of a child. The reasons for implantation failure are poorly understood. One major cause of implantation failure is abnormalities of the uterine cavity such as polyps, myoma, and adhesions. Hysteroscopy has been generally regarded as the standard procedure to detect these uterine abnormalities. It is thought to improve pregnancy rates in women scheduled for IVF by detection and surgical removal of uterine cavity abnormalities, dilatation of the cervical canal, or induction of inflammatory reactions in the endometriumby the procedure itself. Hysteroscopy is often performed routinely in infertile women scheduled for their first IVF cycle. However, there are no data from well-designed randomized controlled trials to support this practice. The inSIGHT trial is a pragmatic multicenter randomized clinical trial designed to determine whether routine hysteroscopy before the first IVF treatment cycle increases the live birth rate. The trial was conducted in 7 university hospitals and 15 large general hospitals in the Netherlands. Women eligible for the trial were infertile, scheduled to start their first IVF or ICSI treatment, had no previous hysteroscopy, and had a normal transvaginal ultrasound of the uterine cavity. Subjects were randomly assigned in a 1: 1 ratio to hysteroscopy with treatment of detected intracavitary abnormalities before starting IVF followed by IVF (hysteroscopy group) or to immediate start of IVF treatment (immediate IVF group). Web-based randomization was done with a variable block size to allocate patients to groups and was stratified by center. The doctors, outcome assessors, and participants were not masked to the assigned group. The primary study outcome was an ongoing pregnancy (detection of a fetal heartbeat at > 12weeks of gestation) within 18 months of randomization and a live birth. Analysis was done according to intention to treat. Between May 25, 2011, and August 27, 2013, 750 women were randomized: 373 to the hysteroscopy group and 377 to the immediate IVF group. A live birth occurred during the trial period in 209 (57%) of 369 women in the hysteroscopy group and 200 (54%) of 373 in the immediate IVF group; the relative riskwas 1.06, with a 95% confidence interval of 0.93 to 1.20; P = 0.41. These findings demonstrate that hysteroscopy does not improve live birth rates in infertile women scheduled for their first IVF cycle, who have a normal transvaginal ultrasound of the uterine cavity. Therefore, routine hysteroscopy should not be performed in women with a normal transvaginal ultrasound.