Epidurals ease post-partum depression? Release relies on weak finding of association

Does the news release adequately discuss the costs of the intervention?

Not Satisfactory

The cost of a birth with an epidural isn’t mentioned. While it depends on the insurance carrier — some pass all or part of the costs of anesthesiology during birth onto consumers — the average epidural in the US adds about $1,200 to a birth bill, with some anesthesiologist practices charging more than $2,700 per epidural.

Does the news release adequately quantify the benefits of the treatment/test/product/procedure?

Not Satisfactory

There are no hard numbers in this release, and that’s a big shortcoming. Journalists and other readers are left imagining just how strong or weak this association is, and what percentage of women might benefit — or not. The best we get is “some women” of 201 who chose to receive an epidural are less likely to experience postpartum depression.

To its credit, the release added some cautionary language regarding the study’s findings:

“Although we found an association between women who experience less pain during labor and lower risk for postpartum depression, we do not know if effective pain control with epidural analgesia will assure avoidance of the condition,” said Dr. Lim. “Postpartum depression can develop from a number of things including hormonal changes, psychological adjustment to motherhood, social support, and a history of psychiatric disorders.”

Does the news release adequately explain/quantify the harms of the intervention?

Not Satisfactory

We’re not told about any of the risks of epidurals.Those risks include a drop in blood pressure (which can complicate an otherwise normal pregnancy), severe headache (in less than 1% of women), slowing of labor due to lying on one side for too long (unless a “walking” epidural is used, though the procedure is rare), shivering, backache, ringing of the ears, nausea, trouble urinating, and the increased likelihood of interventions like forceps and cesarean section (since it can be harder to push). Epidurals also require a catheter to drain urine, which significantly increase the risk of urinary tract infections.

Does the news release seem to grasp the quality of the evidence?

Not Satisfactory

Correlation is not causation, and this release doesn’t go far enough to explain this. The release quotes lead researcher Dr. Grace Lim, who is the director of obstetric anesthesiology at Magee Women’s Hospital of the University of Pittsburgh Medical Center, as saying “We found that certain women who experience good pain relief from epidural analgesia are less likely to exhibit depressive symptoms in the postpartum period.”  However, it also stands to reason that some women — whether or not they have an epidural or go on to develop post-partum depression — simply experience less pain.

The release does include a brief caveat regarding the association between epidurals and post-partum depression: “…we do not know if effective pain control with epidural analgesia will assure avoidance of the condition.” And, helpfully, it calls the research “early” and “preliminary.”

The release states the study controlled for two major confounding factors: “pre-existing depression and anxiety” and “post-delivery pain caused by tissue trauma during childbirth.” But that does not mean women who gave birth weren’t already at risk — i.e. they may not have been diagnosed. Also, we aren’t told whether the study accounted for other risk factors known to play significant roles in leading to postpartum depression, including: availability of family and social support; employment status and financial well-being; the mother’s physical health; infant behavior (e.g. colic); whether a pregnancy was planned; and other sources of acute stress. The release mentioned some of these in a quote from a study leader but, again, we aren’t told if the study actually controlled for these conditions.

Does the news release commit disease-mongering?

Not Satisfactory

We found the statement that labor pain “may be psychologically harmful for some women and play a significant role in the development of postpartum depression” a gratuitous assessment, especially given that humans have been bearing children for hundreds of thousands of years without modern analgesics. This statement might scare women away from a perfectly viable alternative, i.e. birth without medicated pain relief.

Does the news release identify funding sources & disclose conflicts of interest?

Not Satisfactory

The release doesn’t mention who funded the study.

Does the news release compare the new approach with existing alternatives?

Not Satisfactory

The best comparison we get to alternatives is a bit of minor scaremongering. This release really should have brought more to bear on births where women choose to not to use an anesthetic, also called “natural” birthing. It should also be noted that nitrous oxide is increasingly being offered as an alternative in hospitals around the US. That’s worth noting.

Does the news release establish the true novelty of the approach?

Not Satisfactory

While technically a novel result, it’s a minor one. We found a 2014 study in Anesthesia & Analgesia that explored the same question, though in a Chinese population and with greater rigor. That study compared women who chose epidurals to those who chose a “natural” birth without epidurals. Interestingly, we found a 2015 commentary that responds to this 2014 study — and it was authored by Lim (the lead author of the new study), who rightfully states that, if epidurals do decrease the risk for postpartum depression, then “it could have tremendous ramifications on the long-term mental well-being of half of the world’s population who are of child-bearing age.” Lim’s letter also called for more research with larger sample sizes to try and replicate the results. But roughly one year later, Lim’s abstract explores the question with no overt controls and a similar sample size.