Lower doses of IVF drugs?

There have been a number of articles about "mild" or "soft" IVF in the last few months, all suggesting that the higher doses of fertility drugs often used in the UK and USA during fertility treatment are potentially hazardous as they can lead to hyperstimulation. One recent piece described OHSS, or ovarian hyperstimulation syndrome, as a "little-known" side effect of treatment making it sound as if the condition had only just been discovered.   While it may well be little known to the journalist in question, it is hardly little known to anyone who knows much about infertility and treatment.

What's quite interesting about these articles is that they're all entirely one-sided, only quoting experts who happen to be great advocates of mild IVF and making it sound as if anyone who doesn't do this cannot possibly have their patients' best interests at heart.  Such articles would make far more credible reading if they also allowed space for those who don't use mild IVF to explain why.

While it's true that OHSS can be a very dangerous condition, it is also true that some women are at greater risk than others and that careful monitoring during treatment can reduce the chances of the condition developing.  Generally success rates are lower with mild IVF, which is why fertility specialists choose to stimulate the ovaries to produce more eggs in order to increase the chances of success.  Perhaps in the future we will be able to get excellent outcomes with far lower doses of drugs, but in the meantime it may be more prudent to continue to tailor the dose to the individual to increase the chances of success and reduce the risks.

Fresh or frozen?

An interesting new piece of research has looked at the effectiveness of freezing all the embryos created during an IVF cycle and then replacing them in a later cycle where no stimulation has been used.  It seems there are concerns that when you stimulate the ovaries, this may have an impact on how well the lining of the womb receives embryos. Not only this, but replacing frozen embryos in a later cycle also reduces the risk of hyperstimulation (OHSS).

The suggestion is that freezing embryos and transferring them later could actually increase pregnancy rates and also make IVF far safer for women by cutting the risk of hyperstimuation - although most women who get OHSS have fairly mild symptoms, it can be extremely dangerous.  Now, researchers from Spain have reviewed all the relevant studies in this area and analysed the results, coming to the conclusion that the chance of a pregnancy is as much as 30% higher if all the embryos are frozen for a later transfer rather than transferring them right away.

As is often the case with these rather interesting news stories, those responsible for the study have said that more research is needed to confirm their findings before making any changes to routine treatments for patients - but it will be reassuring for anyone who is having frozen embryos transferred. We often assume that this reduces the chances of success, but the evidence seems to suggest it could be quite the opposite.

Ovarian hyperstimulation

When we think about the risks associated with IVF, we tend to either worry about the possibility of long-term health risks or more often about the risk of the treatment not working. In fact, one of the most serious, and not uncommon, risks of IVF is ovarian hyperstimulation, often known as OHSS.

Stimulating the ovaries to produce lots of eggs is not a natural process, and hyperstimulation is not something that can occur naturally but is a direct result of fertility treatment. Some women are more at risk of OHSS than others, and the team treating you will be keep a particularly close eye out for this if you have polycystic ovary syndrome, if you are underweight or if your have had OHSS in the past. Hyperstimulation can occur during treatment or after successful treatment when the rising hormone levels in early pregnancy can have an effect, which is why women who are pregnant with twins are at greater risk.

When the ovaries are hyperstimulated they become enlarged and the balance of fluids in the body is affected. Fluid can start to gather in the abdominal cavity and this can lead to swelling, dehydration and bloating. Fluid may collect in the lungs too, and the condition can also lead to an increased risk of blood clots. Although OHSS is often mild, the condition can be very dangerous.

Clinics can usually spot women who are at risk of hyperstimulating when they carry out the regular scans during treatment as there will be large numbers of follicles developing. Blood tests can confirm that a woman is at risk. Symptoms of OHSS can include discomfort and swelling in the abdomen, nausea, reduced urine output, dehydration and breathlessness. The first thing that women notice is often a swollen stomach, and the swelling can seem to increase very rapidly.

Ovarian hyperstimulation is thought to occur in about 5% of women having IVF treatment. Although the condition is often mild, it is always important to get medical advice immediately if you suspect you may have OHSS as it can be dangerous. If you are in the middle of a treatment cycle, you may be advised to "coast" for a few days without taking more stimulating drugs to see what happens. If you are close to egg collection, the embryos may be collected and frozen so that they can be replaced safely later.