The Environmental Factors That Could Lead to Miscarriage with guests Dr. Dana McQueen and Dr. Audrey Gaskins
In today’s Egg Whisperer Show podcast, I’m joined by Dr. Dana McQueen and Dr. Audrey Gaskins. Dr. McQueen is a fertility doctor at University of Chicago, where her area of interest and research is recurrent miscarriage and recurrent pregnancy loss. Dr. Gaskins is an assistant professor at Emory University, where she studies the relationship between the environment, dietary factors, lifestyle factors, and fertility and miscarriage in both men and women. She received her Bachelor of Science from Duke. Then she went to Harvard for public health. This episode, which is part of a recurrent pregnancy loss series, is focusing on the environmental factors that can play a role in miscarriage. We’ll be sharing all sorts of great evidence based information on pesticides, organic food, pollution, and endocrine disrupting chemicals. All the things that you guys have questions we’re definitely going to be talking about today.
Dr. Aimee: Welcome to the show, Dr. McQueen and Dr. Gaskins!
Dr. Dana McQueen: Thank you for having me back.
Dr. Aimee: I’m so excited to have you and talk about this stuff. It’s near and dear to my heart as well.
Dr. Dana McQueen: We’re excited to talk to you about the environmental factors that could lead to miscarriage, because there’s a lot of information out there and it’s hard to know what to believe, what’s important and what’s not important.
Dr. Aimee: One of the questions I get a lot, because I get questions from all over the world, is about the pollution in the air and how that plays a role in fertility and miscarriage. Audrey, can you talk a little bit about that air pollution in certain areas of the world and maybe how that makes a difference?
Dr. Audrey Gaskins: Sure. That’s been a really growing area of research, even just in the past five years. There have been studies from the US, studies from China, and Europe, and they’ve all pretty consistently shown that women (or couples) that have higher exposure to air pollution, particularly air pollution from traffic, so exhaust from vehicles, typically this happens when couples live closer to major roadways, those couples have a longer time to pregnancy. Also, among couples undergoing assisted reproductive technologies, they have a higher risk of failure, so a lower probability of live birth.
Dr. Aimee: Do you know, are there certain cities in the country that are potentially at higher risk?
Dr. Audrey Gaskins: If anything, we’ve seen it in all regions. Even comparing countries like China, which in most cities have pollution that are ordered with magnitude higher than most cities in the US. They’ve seen detriments in the US where we have much lower levels. We’ve still seen a gradation in risk suggesting that women with higher exposure have lower fertility.
It doesn’t necessarily mean that only one place is affected versus the others, but again, where you live within cities, as much as you can lower your personal exposure seems to be the most consistent way to reduce that risk.
Dr. Dana McQueen: How are you studying this? How do you figure out where someone lives in relationship to pollution? Are you going around doing air samples or just figuring out where they are in relationship to highways?
Dr. Audrey Gaskins: We collect residential addresses of the men and women in our study. One of the main studies I work on is a study where we follow couples prospectively through their infertility treatments, so we know where they live when they’re undergoing treatment. Then we link those residential addresses to these existing air pollution models. It basically uses information on everything from roadways and traffic volumes to point sources of air pollution, so certain factories, weather conditions, all these different things, so we can really narrow down on a finer scale what somebody is exposed to. It can differ based on one kilometer distance.
Dr. Aimee: I always get that question. Dana, I’m sure you get it all the time, too. “We’re painting the baby’s room today. Should I worry?” And there’s that acute versus chronic exposure. This being your field of research, what would you say to someone who is going to paint a room and they’re already pregnant or they’re trying to conceive, what do you think is the best advice?
Dr. Audrey Gaskins: One area where there really hasn’t been much research is on indoor air pollution, and that’s because we don’t have as great of measures of that. We really have to take a personal sampling approach, and that’s hard to do on a large scale. We’re mostly worried about volatile organic compounds, VOCs.
When I get asked this question by friends, I always recommend to wear a mask. An acute exposure like that is probably not going to be as harmful as something that’s more chronic, if you were employed as a painter and you did that every day, all.
Dr. Dana McQueen: Does it build up in your system over time then?
Dr. Audrey Gaskins: Yes. It depends on the chemical. There are some that we breathe in and then we excrete pretty rapidly. Then there are other more persistent chemicals that are stored in adipose tissue and are harder to get rid of. A classic one would be like lead in paint, which is no longer in the paint that we’re using, but if you were sanding a wall in an older home that can put the lead in the air that you inhale, and it would get into your body.
Dr. Aimee: Aside from moving, what can we do to reduce our risk if we’re in a location that we might be exposed?
Dr. Audrey Gaskins: There are a couple of things that we recommend. One is keeping track of the air quality in your neighborhood. On days where there’s higher alerts and poor air quality, things like keeping your windows closed, reducing your time outdoors, particularly during rush hour and other times where there are peak air pollution levels.
Reducing all indoor sources. The biggest one is not letting people smoke in your home. Also, turning on the exhaust fan when you’re cooking, that’s another big source. If you live in an area like the Pacific Northwest where there are more wildfires, you can also invest in an air quality monitor. That’s another thing that can help with these kinds of short-term very high levels.
Dr. Dana McQueen: I wanted to segue into another topic that people ask a lot about. That’s plastics or these endocrine-disrupting chemicals. What are endocrine disruptors, or what are endocrine-disrupting chemicals, what are examples of them, and how do they interfere with a woman’s body or reproductive system?
Dr. Audrey Gaskins: Endocrine-disrupting chemicals is an umbrella term that we use to describe any exogenous chemical that interferes with hormone production. It could either mimic something like estrogen or it could antagonize it, meaning that it blocks it. Estrogen is just one example, but there are plenty of other reproductive hormones that chemicals can mimic as well. By interfering with one hormone, it will usually involve a cascade from there, so it will cause a variety of different health effects.
Dr. Dana McQueen: It can even impact egg quality and the spindle of the egg. It’s so interesting. I know BPA is one example. Can you tell me a little bit about BPA? Or what specific endocrine-disruptors have your studied or are you interested in?
Dr. Audrey Gaskins: We’ve studied a lot of what we would call more short-lived endocrine-disrupting chemicals. You mentioned one of the most popular, BPA. That’s largely been phased out because of the research that has come out showing that it’s potentially affecting various outcomes, not even exclusive to fertility. But now it’s being replaced with BPS and BPF, and all the other letters of the alphabet. We think that a lot of those chemicals act in the same manner, so I would try to avoid them to the same extent that you would avoid BPA.
Another common one that we’ve studied and that people are now hearing about are phthalates. These are found in personal care products, like makeup, they’re found in beverage and food containers, they’re found in IV bags and medical materials, they’re found in the coating of some pharmaceuticals, so they’re all over. Phthalates have been started to be phased out, things like DHP, but again they’re replacing them with other very similar phthalates, which now that the science is catching up, we also think those are harmful as well.
Parabens are another one we commonly see talked about. Those are found mostly in cosmetics. Again, the research is growing, suggesting that they have hormone-like activities and they might interfere with the endocrine system.
The easiest way to avoid the majority of those is by avoiding plastics. All of the things that you’ve heard about in terms of avoiding BPA, so avoiding storing food in plastic containers, avoid putting things in the microwave in plastic containers. Anything with a fragrance likely has some sort of paraben or plasticizing chemical in it, that’s how it retains that scent. It’s hard to completely avoid them, they’re so ubiquitous, and it could drive you crazy, but doing the best that you can to minimize exposure is, I think, the key message.
Dr. Aimee: There are two cool companies. Million Marker, I don’t know if you’ve ever heard of that company, Jenna Hua is the creator of the company. It’s a urine test that actually measures these things in your urine. You can do a journal or diary before and a diary after, and then repeat your test to see what the difference is over time from the exposures and the stuff that you’ve changed, like your beauty products, your deodorant, your toothpaste, etcetera. Some people might be interested in that. That’s something that I’ve learned about more recently.
Dr. Audrey Gaskins: The Environmental Working Group (EWG) also has a great database, if you’re interested in looking at consumer products and where they rate in terms of safety and what chemicals they contain.
Dr. Dana McQueen: Is there anything in the ingredients that I could see in a beauty product? All of my beauty products are coming in a plastic container, it seems like.
Dr. Audrey Gaskins: Right. One trend I’ve seen that I’m excited about is consumers are demanding more clean beauty products, which is great because that’s honestly the quickest way to drive changes in companies’ behavior. A lot of times now you’ll see products labeled as phthalate and paraben free. That’s a good marker to look for.
As I mentioned before, fragrance is usually a sign that a paraben or similar chemical has been added. That’s another easy way to avoid unnecessary chemical exposures.
Dr. Aimee: Dana, you probably get a lot of questions about organic and pesticides and when we should eat organic. What do you think, Audrey, about pesticides and whether organic product is really worth it or not?
Dr. Audrey Gaskins: We actually did a really interesting study where we asked women what they were consuming prior to undergoing an in vitro fertilization cycle. We had them fill out a standard food frequency questionnaire, so we asked them how often do you eat a variety of different fruits ad vegetables in addition to all of the different other food groups.
When we classified fruits and vegetables according to their pesticide residual status — and this data is collected by the USDA routinely every couple of years — we saw that women who ate fruits and vegetables that have a higher pesticide status actually had a higher risk of miscarriage once they’re embryos were transferred. This was shocking to us because this is a pretty crude measure of someone’s pesticide exposure, but it suggests that even this low level of exposure through diet, not occupational exposure, that’s something that we’re chronically exposed to could be having a harmful impact on something like miscarriage.
Dr. Aimee: What are some foods that you think are really important to choose? If you were to go to the grocery store and pick, what would be the most important ones that you would say should be organic?
Dr. Audrey Gaskins: Unfortunately, strawberries are always most of the contaminated fruits. Apples, same thing, are always in the top 10. Spinach is always in the top 10. Most berries, I would say.
The way I described it to a friend was like if a critter would look at something and find it really delicious, they probably need to put pesticides on it. Things like bananas that have a harder, thicker skin, they tend to have lower levels, or things that are grown underground.
Dr. Dana McQueen: Things you can peel, I would think that you’re not getting as much exposure to pesticides. Is that a reasonable assumption?
Dr. Audrey Gaskins: Right. Even, for example, if you were to peel an apple, the pesticide still gets through the skin. Actually, when they measure pesticides on the produce, when the USDA does this, they prepare the fruit as if you were eating it. They peel the banana, they don’t measure it on the outside of the banana. But, yes, on the whole, the fruits with thicker skin tend to have lower levels.
Dr. Dana McQueen: What about washing fruits and vegetables, does that get the pesticides off, are we getting a lower exposure if you wash them?
Dr. Audrey Gaskins: Yes. That definitely helps. You should definitely wash your fruits and vegetables, yes. That will not do any harm.
Dr. Dana McQueen: Have they done experiments where you actually measure pesticide exposure in the urine and then look at pregnancy outcomes of those women? I know you said this was what people reported having eaten. But are there actual bio measures that you can make?
Dr. Audrey Gaskins: Yes. You can measure metabolites of certain pesticides in the urine. There you have to be more specific about the certain pesticides you’re looking for, because there are a lot of different classes. But yes, there have been studies that have shown that women who have higher levels of these metabolites in their urine also have lower fertility and higher risk of pregnancy loss.
The next most common question I get asked is, “How long before do I need to make all of these changes if I want to see an impact?” That’s a really hard question for us to study because most of the research we’re doing is just observational. We’re measuring things in men and women, but we’re not changing their behavior. We don’t know if we were to intervene and put women on an organic diet or reduce their phthalate exposure what that impact would be or how long they would have to go on that intervention to see a benefit. But that’s definitely an interesting question and one that I think would really help inform patients and consumers.
Dr. Aimee: Do you think that there are any supplements that people can take that can help if they’ve been exposed to pesticides or air pollution? Is there anything that they can do, like a cleanse that you hear are popular with other things, is there something out there like that or are those all scams?
Dr. Audrey Gaskins: One thing that we’ve actually seen is oftentimes maintaining a healthy diet and taking a supplement that has a high level of folic acid may be able to offset a lot of the negative reproductive consequences of some environmental chemicals. For example, with air pollution we saw that women who consumed more than 800 micrograms of folic acid, about double what the recommended daily amount is, the effect of air pollution was essentially null in those women, meaning that there was no effect. In women who were consuming lower amounts, there was a pretty strong negative association.
Other studies have seen similar association with higher intake of antioxidants. With birth outcomes, they’ve seen it with fish and other omega-3 kinds of fatty acids. So, there is some suggestion that what you eat may counteract some of the bad things.
Dr. Aimee: That’s cool. I imagine that would be for sperm as well.
Dr. Audrey Gaskins: Yes.
Dr. Aimee: So, for the egg source and the sperm source, they should both be taking a prenatal.
Dr. Audrey Gaskins: Yes. Exactly. In terms of a cleanse, no, I haven’t seen any great literature on that. But a standard prenatal, yes, that’s always been shown to be beneficial.
Dr. Aimee: I think this is all great advice. Don’t you think, Dana?
Dr. Dana McQueen: This is awesome. You said that you studied some male factors, too. The impact on male fertility, or what exactly were you looking at for the male side?
Dr. Audrey Gaskins: On the male side, we typically rely on semen quality as our proxy for male fertility, which is admittedly not the best marker. Although, we also have followed couples through their infertility treatments, so now we have a couple of studies that have also included the more clinical outcomes like pregnancy and live birth following in vitro fertilization.
On a whole, we’ve found that exposure to endocrine-disrupting chemicals, things like phthalates and BPA, were associated with lower sperm counts, again, as plenty of other researchers have found. The impact on the actual clinical outcomes following IVF were pretty modest. One explanation for this could be the fact that in IVF we circumvent a lot of the male issues by using ICSI and other techniques, and maybe there’s less of an impact in that setting than there might be among couples trying to conceive on their own or spontaneously, but we really don’t know. That literature following men past the semen quality endpoint is very sparse.
Dr. Dana McQueen: Mostly what you’re talking about is the infertility population that’s going through IVF. I don’t know which center you’re specifically working with. I think it’s in Boston, right?
Dr. Audrey Gaskins: Yes.
Dr. Dana McQueen: So, you’re working with these groups that are doing IVF. Have you studied these same questions in an RPL population? My population, I do see infertility patients, but I also see a lot of patients who have recurrent pregnancy loss but don’t have infertility. We like to follow them prospectively, they may not get IVF, but we’re watching to see what the outcome of their next pregnancy is. Have you done these questionnaires or figured out if these exposures impacted the RPL patients at all?
Dr. Audrey Gaskins: Not specifically women with recurrent pregnancy loss, but that’s a great point. There are a lot of interesting subgroups of women that there may be a good strong hypothesis to investigate this question further.
We’ve done studies, like I said, in couples who were conceiving spontaneously. They may have varying reproductive history from nulligravid to multiple pregnancy losses, but we look at them all similarly. We usually don’t have a big enough sample size of the women with recurrent pregnancy loss to really look specifically at them.
Dr. Dana McQueen: One of the things that I’m working on is there’s a group called The Recurrent Pregnancy Loss Association. They’re new, but they’re trying to help fund research in specifically recurrent pregnancy loss. One of the things that I’m focused on doing with them is creating a registry of women or couples that have recurrent pregnancy loss, where they can put in information and allow us to try to make these connections in a broader way.
What kind of information would you need in this registry? Do you need specific addresses or is the zip code enough to know if someone was exposed to pollution? What kind of information would you need?
Dr. Audrey Gaskins: Oftentimes, we would get a residential history, so asking people where they’ve lived. The more specific we can be, the better. Specifically for the traffic related air pollutants, because even being within 50 meters versus 100 meters of a major highway makes a really big difference for that specific pollutant. There are other ones that are more spatially homogenous and depend more on time and things like fine particulate matter. For some of the traffic related ones, we’d want to know exactly where they lived.
For the other environmental chemicals that don’t depend on where you live, it’s harder to get that information. We really need a urine sample, ideally time to when we’re interested in the outcome.
There are some more long-term chemicals that we can measure in blood. Because these chemicals have such long half-life, we can then estimate backwards what their exposure might have been in the past. Those would be easier to measure. Things like perfluorinated chemicals, PFAS, things that people have probably heard about.
Dr. Dana McQueen: Let’s say we were going to save urine on patients who have recurrent pregnancy loss at their first rate of hormone. They come in for their pregnancy test and you get a urine sample. Can I save that and then test it in the future for all sorts of exposures, or are they going to dissolve over time and evaporate?
Dr. Audrey Gaskins: You can freeze them. That’s what we do. We freeze them and then we send them in batches. That’s totally fine.
Dr. Dana McQueen: How much volume do you need, do you need a whole container of urine?
Dr. Audrey Gaskins: I can’t remember. It’s getting progressively lower the amount you need to measure these chemicals.
The downside about urine and the metabolites we usually measure is that they’re short-lived chemicals, because we’re excreting them in the urine, so they typically reflect exposure over the past 24–48 hours. With those short-lived chemicals we usually try to get multiple urine assessments from them to get a better picture of their longer-term exposure.
Dr. Aimee: What about exposures to things like tampons or diapers and even lubricants? What do you think about that, do you think people should avoid tampons and maxi pads and things?
Dr. Audrey Gaskins: From the literature that I’ve seen that directly addresses this question, and they’ve looked at women using tampons versus pads versus other types of menstrual cycle protection, they haven’t seen strong associations. I wouldn’t say that literature is super concerning. That being said, I don’t know why you wouldn’t avoid tampons with fragrance and other potentially harmfully chemicals in them. Again, you can absorb those through that part of your body. It’s not like that part of your body is immune.
Dr. Aimee: Someone asks, “Should we avoid the silicone storage bags for food? What about Tupperware?”
Dr. Audrey Gaskins: Silicone is great. That’s actually one of the materials that we say for people to use, it’s a great alternative. Same thing with glass. That’s been around for a long time, that’s probably one of the safest food contact materials. Silicone and glass, you really can’t go wrong.
Tupperware, if we’re talking about the plastic Tupperware, unfortunately not.
Dr. Aimee: Okay. What about electronics? Someone is asking about keeping your computer on your lap.
Dr. Audrey Gaskins: There was a lot of buzz about that a while ago because there were a couple of reports showing that men had lower semen quality if they kept their laptops on their laps, but that mostly, from my perception, related to the heat that was generated from the laptop, because the scrotum likes to be below body temperature to produce sperm. There’s less concern, I think, about the electromagnetic radiation. That literature hasn’t shown to be that concerning right now.
Dr. Aimee: Got it. Your wi-fi signal isn’t going to affect your fertility.
Dr. Audrey Gaskins: Not that we’ve seen.
Dr. Aimee: Good. What about hair color or bleach, what kind of role does that play when it comes to our fertility and RPL? If there is literature out there, it would be interesting to hear what your perspective is?
Dr. Audrey Gaskins: That’s a great question. We haven’t addressed that specifically in our studies, but there is a lot of great literature showing, for example, that women who use those hair products like the bleach and the straighteners do have a higher burden of exposure to these endocrine-disrupting chemicals and suggesting that might be a primary route.
Then on top of that, it could be one reason for the racial disparities that we see with fertility outcomes, specifically in non-Hispanic white versus Black or African-American women. There are a lot of great researchers doing work in this area and really trying to investigate that question further, like Tamarra James-Todd who is really looking at that question and doing a great job.
Dr. Aimee: Great. What about Ziploc bags?
Dr. Audrey Gaskins: I saw that one. That one we would be less concerned. That type of flexible plastic would not contain phthalates or BPA, so that’s generally fine.
Dr. Aimee: Oh, good. I didn’t know that.
Dr. Dana McQueen: What about breast milk bags? Those are mostly plastic. I know that patients will often store their milk in a breast milk bag.
Dr. Audrey Gaskins: That’s very common. Those are, again, mostly fine. I wouldn’t heat them up super high temperatures or anything like that, but for storage in the freezer those are okay.
Dr. Aimee: Good. I think we just answered a whole bunch of questions that I typically get every single day. Now I can say Dr. Gaskins told us this based on her research.
Dr. Audrey Gaskins: Awesome. Thank you so much.
Dr. Aimee: Thank you to both of you. Thank you for all of your work. Thank you again, Audrey, for your time. We appreciate you and all that you do.
Dr. Audrey Gaskins: It was great talking with you.
Dr. Aimee: Thanks again. Likewise. Take care. Bye, everyone.
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