Recent research published in the BMJ explores using Metformin to prolong a pregnancy after diagnosed with preterm preeclampsia (source). Here is what you need to know:
There has been interest in Metformin as a possible treatment for preeclampsia for a while. A few years ago, scientists noticed it promoted the growth of placental tissue in petri dishes, but were not sure how to apply this to human patients. Other studies have looked at patients taking Metformin for other reasons like PCOS or T2D. They still got preeclampsia at similar rates. From this, it does not appear to be a prevention, but more studies are needed. This is one of the first studies to see if it prolongs pregnancy, even if it does not prevent preeclampsia entirely.
This was a randomized, double-blind study, the “Gold Standard” of research. Patients who were diagnosed with preterm preeclampsia were assigned to either the Metformin group or the Placebo group. Researchers looked at how long they stayed pregnant after diagnosis while taking these treatments. The Metformin group stayed pregnant an average of 7 days longer than the placebo group. This is very promising!
A Word of Caution
This was an early study, with only 180 participants, 90 of which took Metformin and 90 controls. When you have a small sample size like this, it is possible that more patients who were going to have a better outcome anyway would end up in the treatment group just by luck. This can make it look like the treatment had a good effect when maybe it did not. The larger the sample size, the harder it is for this to happen, and the more likely the results are to be accurate.Studies like this need to be repeated with larger groups, and then done again with even larger groups, before we can make firm conclusions. It has often happened in the past that something looked promising in early trials, only to fall apart in bigger studies. We are optimistic about Metformin, and look forward to seeing more studies over the next few years. But we cannot say yet that it definitely helps prolong preeclamptic pregnancies.
Should I ask my doctor for Metformin?
You can certainly ask, but do not be surprised if they do not prescribe it, unless you have the opportunity to join a clinical trial. Doctors have learned their lesson the hard way about jumping into new treatments before the full research process has been completed. In the past, it was common to start prescribing treatments based on preliminary research, only to find out it did not help. This would mean exposing patients to risks with no benefits. Doctors who got used to prescribing something to all their high-risk or complicated patients had to re-learn not to use it anymore.
But Metformin is already used in pregnancy, so it couldn’t hurt, even if it doesn’t help, right?
Again, we cannot say this for sure until more studies are done. Just a few years ago, a medication was being used in clinical trials for preeclampsia (not Metformin). It had passed the first few rounds of study and was thought to be safe. But then, three separate projects in different countries had multiple fetal and newborn deaths. All studies on this medication were immediately stopped and the research reviewed to see what went wrong. Was the medication actually unsafe, was it just bad luck, was there another factor involved? These studies have still not been restarted. This is why it is really important to wait, even though I know it is frustrating when you are dealing with complications now, and need help and hope now. Yes, scientists want to help those who can be helped, but not causing harm is a greater concern.
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