It is natural for people to enter their first pregnancy with the hope and expectation that things will go smoothly. And often they do! But sometimes they do not. Pregnancy complications — extreme nausea, preeclampsia, prematurity, miscarriage — happen. When they do, in the aftermath, people often wonder: Will this happen again? If I had a preterm birth with my first pregnancy, am I likely to have another? If I miscarried, will it happen again?
When I hear from women with these experiences, one overwhelming sense is that they feel they cannot get a good answer to these “will it happen again” questions. The answers are vague! Imprecise! They do not work for those of us who love data.
So I wanted to ask an expert, and I went to Dr. Nathan Fox, who is my favorite expert. Nate is a maternal fetal medicine (MFM) specialist in New York. He hosts an excellent podcast called Healthful Woman (website, direct link) all about pregnancy, women’s health, and sometimes COVID. I posed my questions, and our conversation is below.
My summary is that he did not have all the answers, but I learned a lot about how to think about and approach the questions.
In practice, when someone has a previous preterm birth, we try to examine the circumstances and whatever data we have from the preterm birth to narrow down the possible causes. That helps us better predict the likelihood of recurrence, as well as a course of monitoring and treatment for this pregnancy. But we usually end up with a range like 20%-50% and monitoring/treatment for several possible causes.
If you agree, I wonder why this is. Is it an inherently unknowable thing? Is there just not enough data? Are we reluctant to attach numbers to it because they can never be “for sure” or “absolutely not,” so having a specific number feels less useful?
In the case of miscarriage, I read what you said at the top as that a single miscarriage is not very informative because, unfortunately, it’s so common. But more than one (or more than two) would entail an evaluation. Is that right? As a side note, this further reinforces my frustration that we keep miscarriage such a secret.
I think many women keep miscarriages a secret out of traditional superstition, but that has been changing over the years. Ultimately, it is a very personal decision whether to share the story of a miscarriage with family, friends, and Facebook, and there is no right answer. However, the story should absolutely be shared with your doctors, as this is something we definitely need to know to help you best.
We’ve been talking about recurrence of experiences related to the outcome of pregnancy. The other piece of this relates to experiences during pregnancy. I’m talking about things like weight gain, nausea, physical discomfort, etc. If I had hyperemesis in one pregnancy, for example, am I likely to have it again? More generally, should people pretty much imagine their experience in multiple pregnancies will be similar?
To summarize, although there is some correlation from one pregnancy to another in these experiences, it is not strong enough or predictable enough to rely upon in either direction. In other words, all bets are off.
Continuing with nausea and vomiting as our example, let’s say I am meeting with someone (not currently pregnant) with a history of hyperemesis gravidarum in a prior pregnancy to discuss her risk of hyperemesis in a future pregnancy. Based on the data, she has a 15%-89% chance of recurrence. That range is quite wide, but I might be able to give an educated guess which end of the range she may be in based on how many pregnancies she had before with hyperemesis, how she responded to treatment, how long it lasted, how severe it was, whether it runs in her family, whether she has other related risk factors, etc., etc. Those are not easily input into a calculator, but since I’ve taken care of a lot of women with hyperemesis, I likely have a pretty good sense of what to ask, and what follow-up questions to ask, to determine where she falls in that range. Also, we may be able to develop a monitoring and management plan for an upcoming pregnancy that could potentially reduce her risk, or at least reduce the severity of the hyperemesis. After that meeting, she will probably have a much better sense of what to expect and what we can do about it, and then she can decide if she wants to embark on another pregnancy. Not exactly a supercomputer, but it’s pretty good.
Here’s a good analogy: Let’s say I am a trial lawyer for the defense and I am about to cross-examine the key witness for the prosecution. Would I rather write up a list of questions to ask the witness and have my law student ask them, or ask them myself? Clearly the latter, because my knowledge and experience will give me the ability to pivot, ask follow-up questions, read the witness, pick up on subtle cues from the witness and the jury, and ask additional questions. The same is true for medicine. If I wanted to predict the outcome of a future pregnancy, I’d much rather have an hour with someone to hear their story and their history and probe into the details than have several data points to input into a calculator.
I think the takeaway message is this: A prior pregnancy has some predictive value for a future pregnancy, but it is usually not precise enough to be useful as a stand-alone predictor. For a clearer picture of what to expect and what we can do about it, I highly recommend meeting with an experienced obstetrician or maternal fetal medicine specialist prior to the next pregnancy. These pre-pregnancy consultations are invaluable to the woman herself and to the doctor. We have plenty of time to go over the history, discuss options, order tests if needed, and think about what to do, with none of the pressure of already being pregnant. I usually block out a full hour for these consultations. It is a much more pleasant experience going into pregnancy with (a) reasonable expectations and (b) a plan!
(If you don’t have easy access to one of these specialists, you can start by listening to my podcast! Also, nowadays in the world of virtual visits, access has opened up significantly. Don’t feel limited by geography to have a consultation — almost always, all we need to do is speak to come to a plan.)
The recommendations are being made on the fly, which isn’t actually that unique in the history of medicine, but this time it is all being done on CNN and Facebook!
So my short answer today is: Maybe probably. How’s that for a hedge?
Emily: Perfect note to end on.
Emily:
Hi! I’m excited to talk about these issues. At a very basic level, I’d say the question is “Will this happen again?” It comes up in a lot of contexts — hyperemesis [very serious nausea and vomiting], preeclampsia, “incompetent” or “insufficient” cervix, miscarriage, stillbirth. And in this thread I’m hoping we’ll dive into a bit of detail about whether there are numerical answers in any of these contexts. But, big picture, I’d like to hear what you’d say in response to this concern.