Oil-based or water-based contrast for hysterosalpingography in infertile women: a cost-effective analysis of a randomized controlled trial

Objective: To determine the cost effectiveness of the use of oil-based versus water-based contrast in infertile women undergoing hysterosalpingography (HSG). Design: Economic evaluation alongside a multicenter randomized trial. Setting: Hospitals. Patient(s): Infertile women with an ovulatory cycle, 18–39 years of age, low risk of tubal pathology. Intervention(s): Use of oil-based versus water-based contrast during HSG. Main Outcome Measure(s): Costs per additional ongoing pregnancy and per live birth within 6 months of randomization, incremental cost-effective ratios (ICERs). Result(s): A total of 1,119 women were randomized to HSG (oil-based contrast, n = 557; water-based contrast, n = 562). After HSG, most women had no additional treatment; a minority had IUI or IVF. In the oil group, 39.7% women had an ongoing pregnancy within 6 months of randomization versus 29.1% women in the water group. There was a 10.7% increase in the live birth rate in the oil group. For ongoing pregnancy, the mean costs per couple were US$2,014 in the oil group and US$1,144 in the water group, with a corresponding ICER of US$8,198 per additional ongoing pregnancy. For live birth, the mean costs per couple were US$11,532 in the oil group and US$8,310 in the water group, with a corresponding ICER of US$30,112 per additional live birth. Conclusion(s): Hysterosalpingography with oil-based contrast results in higher 6-month ongoing pregnancy and live birth rate. If society is willing to pay US$8,198 for an additional ongoing pregnancy, HSG with oil-based contrast is a cost-effective strategy compared with HSG with water-based contrast for infertile, ovulatory women at low risk for tubal pathology. Clinical Trial Registration Number: Dutch Trial Register, NTR 6577 (www.trialregister.nl).