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expert reaction to study looking at fertility after fallopian tube flushing as part of a screening test (hysterosalpingogram) for infertility

A new study publishing in the New England Journal of Medicine investigates the different outcomes when using either an oil-based or water-based contrast for hysterosalpingography in infertile women.


Dr Ali Abbara, Academic Clinical Lecturer in Endocrinology, Imperial College London, and member of the Society for Endocrinology, said:

“We have known for a while that patients suffering from subfertility are more likely to conceive after having an HSG (which is a diagnostic test assessing whether the fallopian tubes connecting the ovaries to the womb are open).  This well-conducted study finds that using an oil-based contrast to flush the tubes during the HSG test can enhance the chance of conceiving during the 6 months following the test, when compared to using a water-based contrast.  220 of the 554 patients having an oil-based went on to have a pregnancy of at least 12 weeks, and 161 of 554 patients having a water-based contrast had an ongoing pregnancy at 12 weeks.  The absolute increase is 10.6% more patients having an HSG had a pregnancy if they had oil-based as opposed to water-based contrast.

“Whilst the intention of the HSG test is to diagnose the existence of a problem within the tubes as part of a standard work-up for subfertility, rather than being intended as a treatment to improve pregnancy rates, this increased conception rate following the test is a useful by-product which can avoid more involved treatments to conceive.  In the past, there have been concerns regarding possible side effects using oil-based contrasts, but this trial found that the rates of side effects such as allergic reactions were uncommon in both groups (less than 1%) and similar whether using water or oil-based contrasts.  Therefore in light of this study, physicians performing the HSG test as part of a diagnostic work-up of subfertility can consider using an oil-based contrast which may yield a further serendipitous benefit on conception rates as compared to using a water-based contrast.”


Prof. Adam Balen, Chair, British Fertility Society, said:

“The hysterosalpingogram (HSG) is a screening test for the assessment of the fallopian tubes in women with subfertility who do not give a history of past pelvic infection or pelvic pain, for whom the more invasive laparoscopy is the preferred option. For many years it has been thought that the act of ‘flushing’ of the tubes during x-ray assessment of tubal patency may enhance natural fertility.  This interesting report is of the largest study to date both to confirm this and also to suggest that the use of oil-based culture media is better than water-based media in achieving this effect.”


Mr Stuart Lavery, Consultant Gynaecologist And Director, IVF Hammersmith, Hammersmith Hospital, said:

“We currently use HSG as a standard investigation at the Hammersmith for our couples suffering with infertility.  HSG gives excellent and accurate diagnostic information about pelvic anatomy, the uterine cavity and tubal patency.

“We have known for many years that many couples go on to achieve a natural spontaneous pregnancy after HSG and we always recommend that couples have lots of sex after their HSG.  This well designed and controlled study now quantifies the beneficial therapeutic effect that this diagnostic investigation can produce.”


Dr Channa Jayasena, Clinical Senior Lecturer in Reproductive Endocrinology / Andrology, Imperial College London & Imperial College Healthcare NHS Trust, and member of the Society for Endocrinology, said:

“It has long been speculated that flushing the fallopian tubes might clear blockages to the passage of eggs to the womb. This exciting and well-designed study strongly suggests that flushing with oil could help some couples with infertility get pregnant naturally. Since flushing with dye is already done to check the fallopian tubes of infertile women, I can see this being a relatively straightforward treatment to implement.”


Prof. Ying Cheong, Professor of Reproductive Medicine, University of Southampton, said:

“An exciting and interesting study, the largest study so far, showing that oil based (Lipiodol, iodised poppy seed oil) flushing to the womb and Fallopian tubes improves live birth by 10% compared to the usual water based flush.  This is a well conducted large scale multi-centre study with sufficient power to answer this question.  The more intriguing question is why does oil-based compound works better than water-based flush?  One of the possibilities is that it better prepares the womb and pelvic environment for the egg and the embryo.  I am sure the results of this study will inspire a whole range of research, investigating the value of poppy seed oil in the treatment of sub fertility.  However, this procedure is performed under medical supervision as part of medical investigation for potential blockage of Fallopian tubes, and is not the same as taking the poppy seed oil any other way.”


* ‘Oil-based or water-based contrast for hysterosalpingography for infertile women’ by Kim Dreyer et al. will be published in the New England Journal of Medicine on Thursday 18 May 2017. 


Declared interests

Dr Ali Abbara: “No declarations of interest.”

Prof. Adam Balen: “No conflicts.”

Mr Stuart Lavery: “No conflicts of interest.”

Dr Channa Jayasena: “No conflicts of interest.”

Prof. Ying Cheong: “No conflict of interest to declare.”


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