Women having difficulty become pregnant may be invited to have their ‘tubes flushed’, a procedure which uses dye to show whether the fallopian tubes are blocked. It has been reported that women are more likely to become pregnant after this test, but no one knows why.
A Cochrane review has been updated with the best available evidence on tubal flushing and its effect on pregnancy and live birth rates. I asked obstetrician and gynaecologist Dr James Duffy to explain what the procedure, properly known as a hysterosalpingogram, involves:
“Hysterosalpingogram (HSG) is pronounced ‘he-ster-o-sal-ping-o-gram’, but fortunately most doctors call it HSG. It is a common part of a work up for women having difficulty become pregnant. Normally eggs produced by the ovaries pass down fine, narrow tubes called fallopian tubes to reach the womb. A HSG can determine if these tubes are open or blocked. If either or both of these tubes are blocked then the chances of becoming pregnant are much reduced.
Patients will lie on an x-ray table, generally flat on their back. The procedure will start in the same way as a smear examination. The doctor places a small tube called a catheter through the neck of the womb to inject dye.
Two kinds of dye are available: dyes which can be dissolved in water (water soluble) and dyes which cannot be easily dissolved in water (oil soluble). Commonly in the United Kingdom and United States doctors use a water soluble dye for HSG.”
If one sort of dye is better than another, this would be helpful to know. It’s also important to ask what evidence there is that tubal flushing improves pregnancy rates and live birth rates and whether this intervention is associated with any harms (adverse events), such as miscarriage.
The evidence for tubal flushing
The evidence comes from 13 randomized controlled trials with 2494 women, brought together in the Cochrane review. The trials compared oil-soluble contrast media (OSCM) and water-soluble contrast media (WSCM) with each other and with no intervention. Here’s what the reviewers found:
- Women having OSCM tubal flushing had a higher rate of pregnancy and live birth than women who had no intervention. The evidence suggests that for subfertile women the chance of an ongoing pregnancy will be increased from 17% without intervention to between 29% and 55% if they have tubal flushing with OSCM
- There was no evidence of a difference in rates of ongoing pregnancy or live birth between women who had WSCM tubal flushing and no intervention, or between OSCM and WBCM when compared with each other, but there was little data available
- There was no evidence of a difference between any of the interventions in the rates of adverse events but these were very poorly reported
How good is the evidence?
Whilst this is the best we have, there were problems with the studies and the quality of the evidence is low, so the reviewers were not able to draw conclusions with confidence. What we have so far suggests that tubal flushing with oil-soluble contrast media may improve the chance of pregnancy and live birth, compared with doing nothing, but we can’t be at all sure. Only four out of the 13 studies reported live birth rates, although this is a crucial measure of the success of fertility treatments. We don’t know which women are most likely to benefit. We also remain uncertain about possible risks of this procedure and these need to be fully evaluated in future research.
The reviewers say “tubal flushing with oily media such as lipiodol could represent a simple, less invasive and cost-effective alternative to other modalities of treatment for couples where the woman has normal patent fallopian tubes. Moreover, it is less likely than other options to increase the risk of multiple pregnancy.” Surely worth exploring further in well-designed trials comparing flushing with OSCM and WSCM and reporting live birth rates.
“In 2007 my husband I decided that after several years of trying for a baby, we needed some help. Our lives were on hold as we lived month-to-month hoping to be pregnant and then facing the disappointment that we weren’t.
After a referral from the doctor our consultant took it all seriously, made us feel important and referred me on to have a laparoscopy with an HSG, where my tubes would be flushed with liquid to identify any blocks. I bought new pajamas for my day in hospital. This was my first general anesthetic. As I came round, fuzzy and woozy, the doctor came to share the results with my husband and I. I was not awake enough to take it all in. He talked about one tube being blocked. We were told we’d have another appointment with the consultant to talk about what next.
As we packed up to go a nurse came by to discharge me. She said, “It happens all the time that women get pregnant after getting their tubes flushed. I hope you’ll be pregnant soon.” This was not presented as fact, but an aside based on her years of experience. I took it that she was trying to give some solace after an uncomfortable procedure, not based on any evidence.
The next month, I was pregnant and now I am a mother of two. When we went in for that procedure we had no idea it might be the catalyst that would change everything. It was never presented as an intervention that might help me get pregnant; the focus was on the process and uncovering problems. I think it would be useful for women considering having their tubes flushed to consider that it could help them get pregnant, that it is a procedure that can lead to a happy outcome, a much-desired pregnancy. This would be welcome milestone for a woman who, like me, had been struggling for years with concerns about infertility.
The research states tubal flushing may improve the chance of getting pregnant. In my case it did result in pregnancy and the birth of my baby. I’d welcome more research into this area, so women could head into a tubal flushing procedure with some confidence that it may help them fall pregnant and with less risk of multiple pregnancy than some of the other options.”
Read more about fertility and women’s health here
Mohiyiddeen L, Hardiman A, Fitzgerald C, Hughes E, Mol BWJ, Johnson N, Watson A. Tubal flushing for subfertility. Cochrane Database of Systematic Reviews 2015, Issue 5. Art. No.: CD003718. DOI: 10.1002/14651858.CD003718.pub4.
Plain language summary of this review: http://www.cochrane.org/CD003718/MENSTR_tubal-flushing-for-subfertility