The truth about Clexane and fertility

Clexane injections during fertility treatment? Controversial. Some research says Clexane helps women to conceive. Others 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. It comes in different strengths. Its active ingredient is a substance called enoxaparin. Clexane is used 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 after recurrent miscarriage and implantation failure.

Clexane is certainly needed when there’s a high risk the blood might get too thick. High doses of synthetic estrogen, common in fertility cycles, may cause this. So can a known blood-clotting disorder, like Factor V Leiden or Anti-Phospholipid Syndrome.

You’ll probably start taking your daily Clexane injections on your embryo transfer day, or from five days before. But your clinic might even start them on day 1 of your stimulating medication. 20 mg daily is common. Doses of 40 mg can be used, though not much higher.

If recurrent miscarriage is the 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 tackling any immunological causes of recurrent miscarriage. In both areas, the jury is out on Clexane’s true value.

A notable early 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 Prednisone. Injections continue until at least 12 weeks gestation. The research suggests a 53% pregnancy rate. We still see that combination, Clexane and Prednisone, in many of our patients’ protocols.

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 one from 2018, looking specifically at non-thombophilic IVF patients, drew a blank too.

Finally, a systematic review, published in the Human Reproduction Update, looked at various studies into low-molecular-weight heparin. It found it improved live birth rates by 79%. But the number of participants involved was quite small. As it often is for fertility add-ons. We predict more substantive evidence in the future.

Should you ask your fertility clinic about Clexane? Maybe – if you’ve experienced problems getting or staying pregnant. Possibly – if immune issues have been identified. 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 pre-filled syringes. Like Menopur and Gonal-f, you injected subcutaneously into your lower abdomen. Some of our patients say Clexane injections are painful. They’re certainly notorious for bruising, so it’s worth asking your clinic how to minimise this. Our top tip? Ice cubes, before and after you inject.