IVF and preeclampsia: is there a link?
For every positive study highlighting the potential of IVF, there’s always another that’s less cheery. You may have read scare stories online suggesting that IVF raises the risk of preeclampsia. Does it really? Let’s take a look at the evidence.
First off, a warning. Preeclampsia is a serious health condition that affects pregnant women, usually during the second half of their pregnancies. Symptoms include high blood pressure, protein in the urine, severe headaches and swelling in the feet, ankles, face and hands. Most cases are mild and treatable. But in severe cases it can be life-threatening for mum and baby. Diagnosing and treating it early is key. That’s why regular antenatal checks and urine tests are important. Don’t skip them.
The idea that IVF could increase the risk of preeclampsia has largely come about as the result of a couple of studies. One, from 2011, analysed data from six previously published studies. Its results appeared to indicate an increased risk of preeclampsia – as much as 40% – in women conceiving via IVF. The study suggested that eggs grown outside of the body (i.e. during IVF treatment) may not implant in quite the same way as unassisted conceptions. This could affect the correct growth of the placenta and, so it was argued, lead to more cases of preeclampsia.
Research presented in 2014 suggested that using donated eggs in IVF treatment could raise the risk of complications – specifically high blood pressure, which is linked to preeclampsia. Around 600 patients in France took part in the study. 18% of the 217 women who got pregnant via donor eggs developed high blood pressure. This was compared to 5% of non-donor-egg patients. But the study was small. Only large-scale, randomized trials have real significance.
In the first IVF study above, the 40% sounds alarming at first glance. But note that no original research was carried out here. They only analysed the results of existing studies. The donor-egg study was, as we have said, also small-scale. Remember, the nature of preeclampsia means that there will always be some women who have a greater risk of developing it anyway – whether they’ve had fertility treatment or not.
For example, age (being over 40), a family history of preeclampsia and a BMI of 35 or more all play into the higher risk category. If you’re expecting twins or multiples, or it’s been 10 years since you were last pregnant, the risk is slightly raised too.
But let’s face it, age, or a long gap between pregnancies, are common for fertility patients. So we stress again: it might not be IVF that’s increasing the risk. And women using donor eggs often have other issues at play, not just age.
On the other side of the fence, another study provides more reassuring results. The researchers used an approach called propensity score matching. This carefully adjusted 27 known variables to improve accuracy. They found that IVF was only weakly associated with preeclampsia. Over 3,000 were assessed – not a bad number.
Our verdict? Be mindful of preeclampsia, especially if you’ve got any of the known risk factors. But we don’t feel the current evidence is strong enough to indicate a definite and worrying link between IVF, donor and preeclampsia. The donor-egg risk is slightly more compelling, so even more monitoring during your pregnancy is wise. Insist on it.
Final thought. Ask your doctor, clinic or consultant if low-dose aspirin is needed during your donor-egg pregnancy. Some studies say it can bring down the preeclampsia risk. But that’s only for donor-egg recipients – not IVF with your own eggs.