The truth about Clexane and fertility

Clexane injections during fertility treatment? Controversial. Some research says Clexane may help certain women to conceive. Other studies question the benefits. So what’s the deal with Clexane and fertility treatment? Time for a closer look at the evidence.

Clexane is a blood thinner, or anti-coagulant, and it comes in different strengths. Its active ingredient is a substance called enoxaparin. Clexane is used fairly routinely in general medicine to stop blood clots. Think deep-vein thrombosis (DVT), pulmonary embolisms and bed-ridden patients who don’t move much.

Clexane is a class of drug called a low-molecular-weight heparin (LMWH). Other brands include Lovenox and Fragmin. In fertility treatment, Clexane is sometimes prescribed in cases of recurrent miscarriage. It can also help when there’s a high risk the blood might get too thick – e.g. when high doses of estrogen are used in certain fertility treatments. Or when there’s a known blood-clotting disorder, like Factor V Leiden or Anti-Phospholipid Syndrome. It’s occasionally prescribed with Prednisolone (see below).

You’ll probably start taking your daily Clexane subcutaneous injections on your embryo transfer day. But your clinic may start them on day 1 of your stimulating medication. 20 mg daily is common. Doses of 40 mg or more may be suitable for certain patients.

If recurrent miscarriage is an issue, Clexane is thought to help prevent blood clots from forming in the embryo and placenta. It may also increase the production of substances involved in successful implantation, thus reducing the ‘immunological’ causes (if these causes exist at all) of recurrent miscarriage. In both areas, the jury is still out on Clexane’s true effectiveness.

A notable champion of Clexane is fertility specialist, Dr. Gavin Sacks. He developed the Bondi Protocol for use by women with repeated IVF failure or miscarriage. The approach combines Clexane with the steroid Prednisolone. Injections continue until at least 12 weeks gestation. The research suggests a 53% pregnancy rate. But the study was small. Like so many ‘fertility breakthroughs’, larger trials are sorely needed.

A study published in January 2015 found encouraging evidence that regular Heparin (not low-molecular) can help to treat recurrent implantation failure. Another study found no evidence that Heparin could help with IVF success.

And a systematic review, published in the Human Reproduction Update in 2013, looked at various studies into low-molecular-weight heparin. They found it improved live-birth rates by 79%. But as the number of participants involved was quite small, they too admitted more research was needed. A Cochrane Database of Systematic Review report called for more randomised controlled studies.

So, a mixed bag. That said, we think it’s worth keeping an eye out for future research on Clexane and fertility. Several studies are currently recruiting participants. Others will report their findings soon. So there could be more substantive evidence in the future.

Should you badger your fertility clinic about Clexane on your next cycle? Maybe – if you’ve experienced problems getting or staying pregnant. Possibly – if immune issues have been identified as a potential issue. Definitely – if you have a blood disorder or other qualifying problem. (Your clinic should know what to do anyway if you’ve been full and frank in your medical questionnaire.)

As for administering Clexane, it comes in handy pre-filled syringes and, like Menopur and Gonal-F, is generally injected into the lower abdomen. Some of our patients have said Clexane injections are painful. They’re certainly notorious for bruising and it’s worth asking your doctor how to minimise this. Our top tip? Ice cubes, before and after you’ve injected.