“Mailbag 26: What does the Fox say” – With Dr. Nathan Fox

Welcome to today’s episode of Healthful Woman, a podcast designed to explore topics in women’s health at all stages of life. I’m your host, Dr. Nathan Fox, an OBGYN and maternal fetal medicine specialist practicing in New York City. At Healthful Woman, I speak with leaders in the field to help you learn more about women’s health, pregnancy, and wellness.

Hey. Welcome to our Mailbag Podcast number 26: What Does the Fox Say? Our first question is from an anonymous listener, and it’s about when to see a fertility specialist. “Thank you so much for your amazing show. I am a therapist, and I work primarily with women with eating disorders. And your podcast has been really educational for me.” Thank you. “I’m currently trying to conceive, and wondering, if you have a miscarriage, if the clock resets for counting the time you should try before seeing a fertility specialist. The typical advice of try for a year seems confusing when you have a miscarriage. Should you try for a year after the loss and then go see an REI, or go after it’s been a full year you’ve been trying, including the time before the miscarriage?”

So, there’s a few things to unpack from that question. And the first is about this clock, this 12 months. And essentially, the idea behind it is that, let’s say someone’s trying to conceive, and it’s not happening for them. At what point does it make sense to sort of go to the next level, so to speak, and see a specialist for fertility? So, REI stands for reproductive endocrinology and infertility. Colloquially, we sometimes call them fertility specialists, same specialty.

And so, the typical recommendations is what you’re discussing, which is to wait 12 months and then see a fertility specialist. But if you’re over, let’s say, age 35, to maybe only wait six months and go. And so, the question, where does that come from? And it’s really…there’s no magic to those numbers, but it’s trying to balance, on the one hand, you don’t want to wait too long and delay, you know, starting a family. What if there’s an issue? What if you need treatment? What if you need a work-up, you know? So, you don’t want to wait too long. So, that’s on the one hand. But on the other hand, you don’t want to necessarily go too early because, for the majority of people trying to conceive, it is going to happen for them. You just give it a little bit of time, right? And every given month, if you’re trying to conceive, the odds of it being successful are ballpark 25%.

And so, if you sort of do the math, you know, it’s very, very common for it to take several months, whatever it is, until you actually get pregnant. Those who get pregnant the first try, maybe they’re more lucky, whatever it is. And so, you’re trying to balance those two, not going too early, not going too late. So, the question is, what is the downside for going too early? Like, why not? Like, what’s the big deal?

So, there isn’t necessarily a downside, right? However, there’s an issue of sort of maybe it’s a cost issue. Maybe it’s availability. If everybody saw a fertility specialist, maybe there won’t be enough, you know, visits to go around and maybe, you know, people would be waiting, people who “need it” will be waiting longer. Fine. Some of the tests that are done could be, let’s say, invasive and maybe cause pain potentially, or complications. Or also, sometimes, you know, when doing fertility work-ups, you don’t always find an obvious answer. Sometimes it’s, like, a little of this and a little of that. And then you’re sort of left with some confusion. Well, do I have a problem? Do I not have a problem? Do I need to undergo treatment? Do I not?

And so, that’s typical recommendations. Now, obviously, these are not hard and fast rules. Meaning, some people may prefer to go a little bit earlier. And I don’t have a problem with that. I don’t think that’s wrong. I think, if the fertility specialist is good, they’ll be able to put into context whether you need a work-up, when do you need a work-up, if you do a work-up, what to do with the results based on how long someone’s been trying.

And also, there are some people who maybe it’s pretty obvious they need to see someone. I know we did a podcast with Dr. Lobel on fertility and infertility. And what she was saying is, you know, someone doesn’t ovulate. They have very, very irregular periods, and they don’t get their periods. She’s like, what’s the point of waiting a year? You know they’re not going to get pregnant. They should see someone earlier versus if someone has nothing wrong with them and no issues with their periods, everything’s perfectly fine, maybe they should wait a little longer. And so, some of this does have to be tailored. So, that’s sort of in general about that sort of clock or that time frame that it is malleable.

Now, your question about whether, let’s say, you’re trying to conceive and it’s been within that year, you get pregnant, you miscarry. Should you then wait another year? Well, it’s really interesting. It depends why you’re seeing a fertility specialist. If the answer is, I’m having a hard time getting pregnant, then I would say, well, if you got pregnant and you miscarried, obviously, that’s horrible. Like, that’s very unfortunate. But at least you know you can get pregnant, right? That’s not a fertility problem. That’s either not a problem at all, which is typically the case of people who have an early miscarriage, or if there is unfortunately a problem, it’s not a fertility issue, it’s a miscarriage issue.

And so, what I would say is if someone is having miscarriages or had a miscarriage, yes, I guess it would…if you were going by this clock, like, by a hard rule, I would say it would because, well, you got pregnant. So, we know there isn’t that concern about getting pregnant. Now, it’s a little bit complex if someone has several miscarriages. Who is it that they should see? And sometimes fertility specialists see people who have miscarriages. Sometimes it’s OBGYN, sometimes it’s maternal fetal medicine specialists, right? So, that’s its own separate issue. But in terms of seeing someone specifically for fertility, I would think having a miscarriage would likely negate the need to see someone for a fertility issue because that person got pregnant.

Again, it didn’t end with a healthy baby. And so, it’s obviously unfortunate. But sort of the other way to see is, all right, at least I know there isn’t a fertility problem that I was able to get pregnant. So, I hope that answers your question. And if you’re speaking of yourself personally, I’m sorry that you had the miscarriage, and I wish you all of the best and luck moving forward.

Next question, also anonymous listener, about the causes of PROM, premature rupture of membranes. “I’m eight months pregnant, and I know you answer a lot of questions about PROM, but here’s another one. At a recent visit, my doctor mentioned that there’s possibly a nutritional component that affects the likelihood of PROM. Have you heard of this? My mom says that both she and my grandmother experienced PROM, and I’m trying to avoid it happening to me, if possible, though I know that is probably futile. Thank you for your amazing podcast. It has been so helpful throughout this pregnancy.” I thank you for those kind words.

So, if we’re talking about PROM, which is premature rupture of membranes, so, that is talking about the phenomenon where when labor starts, instead of it happening sort of the “usual” way, where someone gets contractions, they get more contractions, they get heavier, they get more painful, and then they go into the hospital. And then sometime after that, their water breaks either on its own or the doctor breaks it for them. The other way labor can start is, first, the water breaks and then sometime thereafter, you go into labor or you get induced and go into labor because of that. And it’s called premature rupture of membranes, and the premature means before labor. It’s complicated because we usually use the word premature to mean under 37 weeks. That’s really preterm. So, PROM just means your water breaks, and then you go into labor.

If you’re talking about preterm premature rupture of membranes, which is that phenomenon happening, but also preterm under 37 weeks, we call that PPROM, or PPROM is what we say. So, let’s assume you’re talking…your question was about term, full-term PROM, just where your water breaks before labor.

So, we don’t really know why someone’s labor would start with their water breaking, which is about 10% of the time versus starting with contractions, which is about 90% of the time. It’s not something we understand well. It’s also not something that we understand sort of the given pregnancy, why would one person happen or if they had it in one pregnancy, is it more likely to happen to them in the next pregnancy? Or if someone’s mother and sisters, let’s say, had that, is it more likely to happen to them? We know very, very little about why in one person or in one pregnancy, the labor would start with the water breaking versus the labor starting with contractions. Amazingly, we know very, very little about this.

And so, in terms of the theory that your doctor mentioned that maybe there’s a nutritional component that affects it, what I would say is, we have no idea. Is it possible? Sure. Anything’s possible, although it’s not really something that we know to be true. And I don’t typically recommend people change their nutrition or diet in order to not have this happen.

The other thing is, having PROM is not itself a concern. It’s not a problem. Right? If you’re in the 10% that go into labor by having your water break first, there’s nothing worse about that or better about that than being in the 90% who have contractions first. So, it’s not like one ends up with a higher risk of C-section or higher risk complications or anything like that. So, I would say, it really doesn’t make a difference in terms of the outcome, whether labor starts with your water breaking or labor starting with contractions.

Now, if your question was PPROM, right, that wondering if there’s a nutritional component or a familial component to having your water break early, like, not just before labor, but prematurely under 37 weeks, again, there might be a nutritional component. I mean, there’s some data that really poor nutrition can increase the risk of preterm birth. Not typical in this country, even if people, let’s say, don’t eat that healthy, they’re not malnourished, typically. Obviously, there are exceptions. And if someone, for whatever reason, is malnourished, then, yeah, that can increase the risk of a preterm birth. But if it’s just sort of, like, eating healthy versus eating not healthy or eating one healthy food versus eating another healthy food, as far as we know, it doesn’t really impact the chance of delivering early.

In terms of family history, there might be some connection in family history of delivering early. But again, that’s not well mapped out. And it’s hard to say exactly what the risk would be or why the risk would be there. All right. Hope that answers your question.

Next question is from Daniela, related to COVID and pregnancy, and later complications. “Hi, Dr. Fox. I recommend your podcast to every pregnant mom I come across. Keep up the amazing work.” All right. Thanks for that plug. “My question is about COVID and pregnancy. During my first pregnancy, I contracted COVID during the first trimester. I remember worrying because my baby book told me that my placenta was forming that very week. Fast forward to the end of my pregnancy, I was diagnosed with intrauterine growth restriction around 24 weeks, and I had to deliver my baby early at 33 weeks due to preeclampsia. She was only 2.5 pounds when she was born, but is healthy and thriving today at 20 months. I’ve always wondered whether COVID during my first trimester affected my placenta and caused all this to happen. Now that we are a few years past the pandemic, has any new research come out about this?” Wow. Great question.

So, the short answer to your question is, maybe, but not definitively. And so, all right, let’s unpack that. So, we all remember COVID. Not a good time. And basically, you know, there was a lot of concerns about COVID in pregnancy. The first concern, or maybe the primary concern, that we had was, is this a virus that’s going to significantly affect pregnant women compared to non-pregnant? And, you know, because there are…when women are pregnant, their immune system is lowered. And the fear was we have this, you know, this virus that’s out. It’s a new virus, and it’s very, very dangerous for certain people, seems to be less dangerous for others. Where are pregnant women going to fall in that? Are they going to be sort of in the very high risk group or less so? And that was a major concern, a very legitimate concern.

And ultimately, it turned out that, yes, pregnant women were definitely higher risk compared to non-pregnant. But I would say, it was not as bad as we thought it would be. I mean, we thought it would be really, really bad. And it was bad, but not as terrible as it could have been. So, that was actually, I would think…I categorize that as sort of fortunate that it wasn’t as bad as it could have been. And that was really for the maternal health.

Now, the second question is, does COVID directly impact the baby? Right? There’s certain viruses that can transfer through the placenta and cause problems in the baby, like birth defects, for example. And that was a second fear because we didn’t really know. It’s a new bug. And fortunately, it appears that COVID is not one of those viruses. Meaning, getting COVID in pregnancy does not seem to increase the risk of things like birth defects.

The third question, which is what yours comes in, is COVID a virus that can affect the function of the placenta? And it appears that, yes, COVID can affect the function of placenta. And what we have learned over the years is that women who got COVID in pregnancy did have a higher chance of complications like preeclampsia or fetal growth restriction, which are related to the placenta. So, that’s true, and it seems to be the case. The problem is, since so many people got COVID and they were pregnant, the majority of them didn’t have those complications. And even before there was COVID, a lot of women have those complications.

And so, it’s hard to know in any individual person if someone got COVID and later in pregnancy they had preeclampsia, was it caused by the COVID or was it not caused by the COVID? Again, because most women with preeclampsia did not have…you know, in the world, in the history of time, did not have COVID. And then when COVID was around, most people who got COVID did not get preeclampsia. So, how do we know if it was a coincidence or if it was a cause? And the answer is we don’t know. And so, when you look at these studies, what they’ll say is, all right, if someone’s risk of preeclampsia is 10% at baseline, women who got COVID, maybe it went up as high as 20% or something like that. Again, these are not precise numbers, but somewhere in that range.

And so, it’s hard to know for sure in any individual person like yourself, was your COVID the cause of your preeclampsia, or was it unrelated and it would have happened anyways? And the short answer is, we just don’t know it. We couldn’t possibly say in any person. And it’s not really different from any other risk factors in pregnancy.

So, for example, if someone, let’s say, has IVF, they have a higher risk of getting preeclampsia as well. Similar numbers, baseline is 10%. If you have IVF, maybe it’s 20%. And that person at 35 weeks gets preeclampsia. We don’t really know, was it because of the IVF? If they didn’t have IVF, would they not have gotten preeclampsia? You really can’t tell in an individual person if it’s cause and effect. And so, these are more population type studies. And so, there has been research on it. There is an association, but I don’t know if your specific case, so to speak, did the COVID cause the preeclampsia and the growth restriction?

All right. Next question is from Ashley, and it’s related to not being immune to certain viruses in pregnancy. All right. Another virus question. “Hi, Dr. Fox. Thanks for all you do to educate us on important women’s topics.” Ashley, you’re welcome. Thank you. “I am 33 years old and 16 weeks pregnant. I found out through routine blood work that I am not immune to rubella. My doctor sent a note through the portal to avoid sick contacts and be diligent with hand washing. This came as a shock as I know I had the full vaccine schedule as a child. I will of course follow up with my doctor, but I have so many questions.”

“Does no rubella antibodies mean no measles antibodies as well? I travel frequently, and have family and friends there that I see often. Some friends have unvaccinated kids, which never worried me previously as I knew I was vaccinated. If I avoid my friends’ kids, could a vaccinated friend still pass measles to me? Two friends with unvaccinated children are planning my baby shower. So, avoiding them will be difficult conversation. But I’ve of course put my baby’s safety first.”

“I’m not clear how easy it is for me to get measles and how many of us are walking around with no immunity. Why isn’t a booster recommended? If I do get measles, what happens to my baby? Do I need to avoid airports? I cannot believe this is even a concern in 2025. I hate that fear of modern medicine has put us in this situation. Any advice for a totally panicked first time mom?” All right, Ashley, a lot of questions there. We’re going to talk about all this.

So, first of all, when someone’s pregnant, we usually check them for their immunity to various viruses. The ones we typically check for, at least the ones we check for in our practice, rubella, which is German measles. Then we check for measles. We typically check for varicella, which is chickenpox. We check for parvovirus, which is fifth disease. And those are the big ones.

And we do find…now, I’m going to put parvovirus on the side because there is not a vaccine for that. But for measles and for rubella, which is German measles, and for varicella, chickenpox, there are vaccines for them. They are as part of the sort of standard childhood vaccine schedule. So, we do find that amongst women who are vaccinated as children properly, that a certain percentage of them, we find that they’re…based on the blood testing, they’re not immune to something. So, they’re not immune to rubella or this.

Now, in your particular case, if they told you you’re not immune to rubella, I presume that means you are immune to measles because they probably tested for it and would have told you you’re not immune to that if you weren’t. So, the simplest thing, if you’re going to follow up with your doctor, say, “Hey. What exactly did you test me for, and am I immune to measles?” And the answer probably for you is, yes, I’m immune to measles because presumably they would have told you about it. That’s number one.

Number two, in terms of rubella, German measles, rubella is not a common virus that’s going around. It’s pretty unusual to run into someone with rubella. And so, yes, while, in general, it’s probably a good idea to do hand washing and avoid sick people when you’re pregnant, this or that. The likelihood of it mattering, whether you are or are not immune to rubella, is fortunately pretty low because there’s not a lot of rubella around there.

The third thing is that it’s really interesting. The question is, if someone got vaccinated or they got the condition and they got antibodies, and then you check them when they’re adults and the antibodies aren’t there, does that mean they’re truly not immune to the condition, or does it mean they are immune but we can’t find it in the blood tests, or is it somewhere in between? And I think that’s a little murky.

Several years ago, during one of the last measles outbreaks, everyone was getting sort of tested for their immunity to measles, even non-pregnant people. And what we found is about, like, 10% of people were walking around without antibodies to measles. And the vast majority of them were vaccinated, right, as children, and they just didn’t have the antibodies. But they weren’t all getting measles. So, the question is, maybe they do have either full immunity or some immunity to measles, but we just can’t demonstrate it in the blood. And it’s hard to prove these things because, again, since measles isn’t that common, even if there are outbreaks, since it’s not so common, it’s hard to sort of tease out what someone’s risk might be if they got vaccinated but they don’t have antibodies. How many of them get measles or is it not? It’s a tough study to sort of sort out.

You know, there are boosters for all of these things. So, if we do test someone and they’re not immune, or they don’t show immunity, we do typically recommend a booster. We don’t give the rubella or the measles, MMR, measles, mumps, and rubella, we don’t give that in pregnancy because it’s a live vaccine. And so, there’s some concern about getting it in pregnancy. But that’s something if in our practice someone showed up and they were not immune to rubella, again, vaccinated or unvaccinated, but that’s what the blood test showed, we would recommend after delivering getting a booster. Or what sometimes we like to do is before someone gets pregnant, if someone comes for, like, a preconception consultation, we’ll say, hey, why don’t we check these things now so that if you’re not immune to something, we can give you a booster before you get pregnant so that you don’t have to really worry yourself? Now, also, we sometimes give people boosters, and the antibodies still don’t go up. And does that mean, again, that they’re not immune, or does it mean that we just can’t prove immunity?

So, I think, for you, I probably wouldn’t worry too much. Number one, because since you were vaccinated, it’s possible that even though your blood test isn’t showing immunity to rubella, you may have either full or partial immunity. Number one. Number two, rubella is fortunately not something that you’re probably going to run into a lot. So, it’s not that likely that you would get rubella when you’re pregnant just because there aren’t a lot of people with it. Number three, in terms of measles, most likely, your doctors checked for it. And if they didn’t tell you that you’re not immune, presumably you are immune to it.

Now, in the scenario, let’s say hypothetically, when someone doesn’t have antibodies to measles, what do they do in terms of, like, your scenario, about being around unvaccinated kids? It’s just an issue of sort of what kind of risk are you willing to take? And just because someone’s not vaccinated for measles, doesn’t mean they’re walking around with measles. Right? And so, if the kids aren’t sick, presumably, they don’t have measles. I mean, is it possible? Anything’s possible. But it’s sort of how much protection do people feel they need in pregnancy? And different people feel differently about this. Right? So, if you’re around unsick people who aren’t vaccinated, the likelihood of getting measles from them, while it might not be zero, is really pretty low. And again, not having antibodies to measles does not mean you’re not actually immune at all. It just means we can’t prove it.

I don’t typically tell people they need to avoid airports and, you know, things of that sort. But again, you know, different people feel differently about this. Ultimately, I think, for your particular situation, there’s probably not much to worry about. I hope that made you a little bit less totally panicked. All right. Good luck.

Our next question is from an anonymous listener, and it’s about transferring two embryos during IVF. “Hi, Dr. Fox. Big fan of the podcast.” Thank you. “I was wondering if you think it’s responsible to transfer two embryos during my upcoming IVF cycle. I’m aware that twin pregnancies bring extra risks. For context, I’m a healthy 30-year-old. And my other pregnancies went over term, I had to be induced, and were otherwise uncomplicated vaginal deliveries. Would it be riskier to transfer two embryos instead of one?”

So, this is a question that used to come up a tremendous amount and now comes up less. And that’s really because of a shift in the fertility specialist community about transferring two versus one embryos. Now, the background for this is that if someone’s undergoing IVF, and they put in one embryo, or the fertility doctor technically puts in one embryo, the likelihood of a successful pregnancy is a certain percentage, not my expertise, but let’s say it’s 30%, whatever it is.

If you put in two embryos at the same time, the chance of a successful pregnancy is higher. Let’s say it’s, I don’t know, 40% to 60%. But obviously, the chance of having twins has now gone up significantly from, let’s say, 2%, if you put in one embryo because there’s a chance it could split to, let’s say, I don’t know, 20%. I’m making these numbers up. That’s not my specialty, but whatever. It’s some higher numbered twins. And so, back in the day, there was a lot of discussion about whether someone should have one embryo or two embryos. Is it worth increasing your chance of success, balancing that against the increased risk of ending up with a twin pregnancy? Fine.

Subsequent to this, a few things have happened. First of all, there was some, let’s say, backlash and some introspection, I would say, in the fertility community where they basically said, why are we doing all these two-embryo or three-embryo transfers and causing all these twins and triplets? It probably makes more sense if you want to increase someone’s success. Just if you have two embryos, instead of putting them in at once, put one in. And if it doesn’t work, do another transfer and put it in again. And if you sort of take those two cycles together, your success rate should be similar to if you do two embryos at the same time. And you’ll lower your risk of twinning a lot. And at least half the time, you only have to do it once. That was one thing. And also at the same time, they started doing more and more genetic testing of the embryos, preimplantation genetic testing or PGT. And having a normal genetic embryo increases the chance of success.

And so, what basically happens nowadays is the default is to put in one genetically tested embryo, which maximizes your chances of getting pregnant with one baby, and minimizes your chances of getting pregnant with twins. And that’s sort of the default. And that’s what most fertility centers are going to do and recommend.

Now, every now and again, it comes up that for whatever reason this isn’t working, or for whatever reason, the fertility doctor thinks it might be wise or prudent to do two embryos instead of one. And people ask me, well, what do you think about that? And ultimately, there isn’t a right or wrong answer on my end. Right? So, on my end, from a pregnancy perspective, yeah, having a twin pregnancy is going to be higher risk than having one baby. But sometimes if the fertility doctor thinks that’s really the best thing and it’s really your best chances of getting pregnant, then you got to do what you got to do. Right? And so, we have to decide, all right, are you someone who is sort of a standard risk if they get pregnant with twins? Right. So, it’s an increased risk pregnancy, but, like, sort of “typical” twins. Or are you someone if you got pregnant in twins, it would be so risky that we would probably tell you it’s better not to be pregnant at all?

Now, that doesn’t come up a lot. But there are people who when I meet with them, I’m like, listen, for you, getting pregnant with twins would be a disaster. Like, you cannot do that. You have to do everything you can not to be pregnant with twins. And for that person, I would say, just one embryo and that’s it. Like, put my foot down. That’s the exception for most people. It’s, all right, listen, obviously, you want to improve your chances of getting pregnant. If you understand that you get pregnant with twins, there is an increased risk, let’s talk about it. Here’s what that pregnancy would mean. Here is the risk. Here’s how it’s going to go. And you know, all those things. And if they’re okay with it and the fertility doctor is recommending it, all right, so be it. That’s what we do.

So, for someone like you, right, you’re young, you’re healthy, you had two uncomplicated pregnancies, you went full term, they’re vaginal births, if anyone’s going to get pregnant with twins…again, unless there’s something in there you’re not telling me. If anyone’s going to get pregnant with twins, you seem to be an ideal candidate. Now, could a twin pregnancy in a young, healthy person with uncomplicated deliveries beforehand, could a twin pregnancy be very, very complicated? Sure, it could be. But the chances aren’t crazy high. They’re higher than if you’re carrying one baby, but they’re not insane, so to speak.

And so, ultimately, for you, I would say it’s a conversation like what is the reason they want to put in two embryos? How important is it to the fertility specialist? If it’s something that’s really critical, you seem to be someone who’s at the lowest risk. If you got pregnant with twins, we would talk about what that meant, and then do what you got to do. If it’s really just, like, hey, I’d rather put in two versus one, generally, that’s frowned upon. And all the more so, it’s usually frowned upon by the fertility doctor than they’re not typically going to do it. I hope that helps. Good luck. Hope to see you soon with a pregnancy.

All right, everyone. Thank you very much. We’ll see you next week.

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