Tubal flushing with oil-based contrast ups pregnancy success
Flushing the fallopian tubes with oil-based contrast medium during hysterosalpingography (HSG) leads to a higher ongoing pregnancy rate beyond the previously reported results at 6 months, with significantly shorter time to ongoing pregnancy than flushing with water-based contrast, according to a study presented at ESHRE 2018.
“For decades it has been suggested that tubal flushing with oil-based contrast at HSG improved pregnancy rates,” said Dr Joukje van Rijswijk from VU University Medical Center in Amsterdam, the Netherlands.
van Rijswijk and colleagues have previously shown that infertile women who underwent HSG with oil-based contrast had higher rates of ongoing pregnancy and live births at 6 months from randomization than those who used water-based contrast (39.7 percent vs 29.1 percent, RR, 1.37; p<0.001) in the H2Oil* trial. [N Engl J Med 2017;376:2043-2052]
To find out if the benefit with oil contrast extends beyond 6 months, the investigators followed up on 1,119 participants in the H2Oil trial 3–5 years after randomization, who completed questionnaires about fertility treatments and pregnancies. In the H2Oil trial, participants were randomized 1:1 to undergo HSG with an oil-based or water-based contrast.
Overall, more ongoing pregnancies occurred in the oil-based contrast group than the water-based contrast group (383 vs 344). More than half of the ongoing pregnancies in both groups were achieved through natural conception (54.3 percent vs 51.2 percent). The remaining pregnancies were achieved through IUI** (29.8 percent vs 27.0 percent) or IVF/ICSI*** (15.7 percent vs 21.2 percent). [ESHRE 2018, abstract O-122]
The primary endpoint of cumulative ongoing pregnancy rate at 3 years was greater in participants who used oil-based contrast compared with water-based contrast (83.2 percent vs 80.7 percent).
Furthermore, the time to ongoing pregnancy based on Kaplan-Meier analysis was significantly greater in favour of oil-based contrast (median time to ongoing pregnancy, 10.00 vs 14.83 months; p-value log-rank test <0.001).
After censoring follow-up with initiation of IVF/ICSI, the cumulative ongoing pregnancy rate remained higher in the oil-based group compared with the water-based group (74.2 percent vs 70.1 percent), with significantly shorter time to ongoing pregnancy with oil-based contrast HSG (median, 10.16 vs 17.07 months; p-value log-rank test <0.001).
“Tubal flushing with oil-based contrast does not only result in higher 6-months ongoing pregnancy rates, but also in higher 3-year cumulative ongoing pregnancy rates,” concluded van Rijswijk.
“In our opinion, tubal flushing with oil-based contrast should be offered to infertile women,” she urged.
As the study recruited women aged <39 years with low risk for tubal pathology and without known endocrinology diseases, van Rijswijk cautioned against generalizing the findings to other population of women.