What is the actual scientific issue with ketones during pregnancy?
March 4, 2016 2:50 AM   Subscribe

I am eight months along, have gestational diabetes, and while my blood sugar is fine and under control I cannot seem to get my ketones down to "small" without blowing most of my blood sugar readings during the day. My doctor wants them to be smaller but has not given me any actual information about why, and admitted that they might not be causing a problem at all. Meanwhile, the added stress of trying to consume Just Enough! but not Too Much! sugar is really weighing on me.

I understand that the theory is that if I am passing ketones, then my body is burning fat and protein for energy. My doctor says that might mean I'm not getting enough energy, period. Okay, but I am gaining weight and I have as much energy as most 8-months-pregnant women. Baby is a normal size as far as can be determined. Doctor said she doubted that anything I could do at this stage would be a problem for the baby, but said vaguely that it might cause "metabolic issues" or problems with breastfeeding supply for me.

Are there any scientific studies that actually make it clear what the danger is here?

(I'm not that interested in "well, my doctor 10 years ago said x" or "my equally vague understanding is..." type replies. I want science.)
posted by chaiminda to Health & Fitness (11 answers total) 1 user marked this as a favorite
 
Doctors tend to be more scared of ketones than they should be because they're also produced as a result of ketoacidosis, which is a very bad sign in people affected by Type I Diabetes (i.e. not the kind you have, but the kind where insulin is unable to be produced). It is also produced as a result of ketosis, which is when your body is burning fat for fuel, such as on a low-carb diet. This fat could be from your diet or from your body - so I could see how seeing ketones in the urine would be a sign that a person was not getting enough calories if that person was on a regular carbohydrate-heavy diet. Others can weigh in on whether there are pregnancy-specific factors regarding ketones that should be considered, but there are good reasons to be skeptical of doctors who raise alarms regarding ketones, because they've had it drilled into them that ketones = bad, since they most often arise as a reason of ketoacidosis.
posted by peacheater at 5:04 AM on March 4, 2016


PubMed has a lot of studies on this, but most seem vague or 10-20 years old. I found one mouse study that suggests that organ growth is the main concern (most specifically, size of he heart and brain). I read one note about excessive ketones causing similar symptoms to Fetal Alcohol Syndrome. And this:
"Maternal ketonuria or acetonuria during pregnancy is a concern because it can result in neonatal or childhood neurocognitive dysfunction."

Here is a more lay-friendly write up that has a bibliography for additional reading.

However, the vast majority of abstracts in PubMed seem to echo your doctor-- concern abou maternal metabolic issues and breastfeeding. And none of it seems to be studied independent of general gestational diabetes risks. (I don't know enough about fetal organ development to know risks at 8 months pregnant, but hopefully someone with more pregnancy-specific medical knowledge can back up/interpret the studies.)
posted by instamatic at 5:09 AM on March 4, 2016


Doctors tend to be more scared of ketones than they should be because they're also produced as a result of ketoacidosis,

Ketoacidosis is the condition caused by too many ketones, not the other way round. It is most prevalent in Type 1 diabetics, but can occur in Type 2 and gestational diabetes.

Ketoacidosis is pretty serious (see here for symptoms) and "can cause fetal death at any stage", hence why your doctor wants you to keep your ketone level under control.

You reduce ketones by increasing insulin levels or otherwise keeping blood sugar lower. Given that "hypoglycemia does not appear to have long-term adverse effects on fetal development", the doctor would probably rather you err on the side of lower blood sugar to reduce the threat of ketones, as hypoglycemia is the lesser of the two evils.
posted by EndsOfInvention at 5:27 AM on March 4, 2016


(Disclaimer: I am not a doctor, I am not diabetic, but a family member is a Type 1 diabetic who has been pregnant)
posted by EndsOfInvention at 5:28 AM on March 4, 2016


It would help to know what your diet is currently like. Ketones can occur in the bloodstream as a result of different variables - it's not a linear, if you eat X macronutrient you get Y amount of ketones. You can get small amounts of ketones (ketosis) from eating a low carb diet, such as Atkins or a low carb version of Paleo. You can get large amounts of ketones (ketoacidosis) from having wildly uncontrolled blood sugar, like, send you to the hospital amounts of blood sugar, in the high or low direction. If you had actual ketoacidosis you would know it, because you would have mild brain dysfunction (slurred speech, dizziness). It's not uncommon for diabetics experiencing ketoacidosis to be perceived by others as drunk, which is bad, because ketoacidosis is a VERY serious condition. Here's a link from a UK diabetes website about ketosis vs ketoacidosis.

If you are eating a low carb diet to keep your blood sugar stable, then a small amount of ketones is perfectly fine in normal health. I cannot say whether it is perfectly fine during pregnancy because I just don't know, but I think if low-carb-diet-ketosis was very bad for pregnant women, there would be a lot of very strong medical advice NOT to do low-carb dieting during pregnancy. We don't see this, so I think a small amount of ketones is probably ok. If your ketone levels are high/very-high, indicating ketoacidosis, you would know because your behavior would be affected, and really, if your ketone levels were that high your doctor probably would have hospitalized you. In terms of energy, if you started out a bit overweight, it's possible that your body is just burning stored fat to provide energy for you and the baby, which is fine, as long as you are taking vitamins and getting a good mix of micronutrients from a balanced diet.
posted by permiechickie at 6:53 AM on March 4, 2016


I agree that ketoacidosis (DKA) is probably the concern. I have a family member with Type I who has basically been told that if he ever tests for ketones and they're too high and he can't get them down within a certain time period, it's time to head to the hospital. Although I am not a doctor, Google seems to suggest that DKA is primarily a problem with Type I, but is also possible with Type II and gestational diabetes. However, if your blood sugar is in a normal range, I actually don't think DKA is likely -- it's something that occurs with very high blood sugar + ketones.

It sounds like you're saying that when your blood sugar is higher, your ketones are lower, if I'm understanding you correctly, which sounds odd to me and makes me wonder if you could be reading the urine strips incorrectly, or if something else weird is going on.
posted by rainbowbrite at 6:54 AM on March 4, 2016


It annoys me that EndofInvention seems to know more about this and has explained it better than the OP's doctor.

I had gestestational diabetes and don't remember ketones being mentioned once, but I did lose weight while pregnant and I was unable to breastfeed.

This is my long way of telling the OP to start demanding more answers or see another doctor briefly for a second opinion. You're pregnant. You're doctor can't just mention there's something concerning about your ketones levels, and then not tell you why or exactly how to address the concern. I'm sorry this has come up this way. But yeah, you deserve better medical information. From your doctor.
posted by jbenben at 8:19 AM on March 4, 2016 [5 favorites]


I disagree with most of the posters here-- there are definitely scientific studies on safety of increased ketones during pregnancy, not related to ketoacidosis. I am not saying "yes! It's true! Increased ketones are definitely a health risk for the fetus during pregnancy!" because I don't think there is definitive evidence of that. But I do think her doctor is thinking of the inconclusive studies showing potential neurological impact and being a combination of overly cautious and intellectually lazy not to more fully explain the cost-benefit of using diet to control gestational diabetes vs a higher ketone range vs using medication to control blood sugar.

If I were you, OP, I'd call up the doctor and talk about fetal development at 8 months, and find out if there is any overlap between risks outlined in the journal studies and what fetal systems are developing now. (My gut tells me "slightly elevated ketones can't be a bigger risk than premature delivery, and you've got to be really close to full term by now anyway." I think your doctor is worrying you for nothing. But I don't have the medical knowledge to back that up for reals.)
posted by instamatic at 9:27 AM on March 4, 2016


Some years ago, I used to work as a dietitian (in a team including internists and specialized nurses) with people with different forms of diabetes, including numerous women with gestational diabetes. I don't know anything about you, so this is all just general information with some thoughts of mine.

We didn't routinely monitor ketones at all, just the blood glucose (in the morning and after meals, as well as HbA1C). Honestly, I'm curious to know why your doctor considers it to be necessary, if your blg and HbA1C are consistently within the acceptable range, and you're not on insulin and you're gaining weight normally (i.e. not due to fluid retention, accelerated fetal growth or excessive amniotic fluid?). At our clinic you would've gotten two thumbs up and be told to go on your merry way and report back in 2 weeks, and nobody would've thought about ketones at all. Maybe I don't have all the facts, but I'm... kind of frowning quizzically here.

Btw, your ketones can also be elevated due to stress, strenuous excercise, diarrhea or vomiting, a low carb diet rich in fat/protein, and/or just the common cold. And starvation would cause it too. You are eating enough, aren't you? Hypothesized risks of elevated ketones sometimes gets cited as the reason why pregnant women with overweight or obesity shouldn't try to lose weight, although the last I heard, there was no perfect consensus about that.

I imagine some of the information in this thread may have been scary to read. I know how worried and vulnerable gestational diabetes makes expecting mothers feel. All I can say is that the only fetal development issues I saw were babies sometimes being large for gestational age, which is why labour sometimes got induced a little before the due date. With the average gestational diabetes patient, things went just fine. I think you should call your doctor and ask him more questions. (EDIT: I wonder if he's suspecting that you're dieting?)

trying to consume Just Enough! but not Too Much! sugar

Just to be sure: sugar is not obligatory at all, and added sugar sometimes has to be avoided completely (although if small amounts don't get your post-meal blg out of whack, it's fine). Carbs on the other hand you do need to consume daily, portioned evenly throughout the day (e.g. some cereal at breakfast - an apple for a snack - a sandwich for lunch - crackers with cheese for a snack - rice/pasta/couscous/potatoes at dinner - a couple of mandarins in front of the telly). Maybe this is what you meant anyway.

people affected by Type I Diabetes (i.e. not the kind you have

Well, occasionally gestational diabetes is the first sign of budding DM1 (or LADA), which is why controlling the blood glucose some time after the birth is also important. In those cases the blg usually is difficult to manage already during the pregnancy.

Hang in there!
posted by sively at 10:21 AM on March 4, 2016 [1 favorite]


We didn't routinely monitor ketones at all

Ketones are always monitored in pregnancy because every prenatal appointment they check a urinalysis, which checks for ketonuria.

there would be a lot of very strong medical advice NOT to do low-carb dieting during pregnancy. We don't see this, so I think a small amount of ketones is probably ok

The general advice is not to do any kind of dieting during pregnancy, unless told otherwise by your physician. Pregnancy is not a good time for a diet.

_____________________________
as for ketones, they can be there for a number of reasons as noted above. Starvation ketosis is common. We see ketosis a lot in women who are suffering hyperemesis or even routine nausea and vomiting during pregnancy. Are you staying hydrated enough? I suspect this is more what your doctor is worried about since being dehydrated could influence breastmilk supply, your energy levels, or your electrolytes ('metabolic issues') as well. This is a good article about evidence on ketosis in pregnancy - basically I think the answer is no one really knows exactly what the effects are, so people are just guessing based on incomplete evidence. But it's obviously important to be eating the right diet, staying well hydrated, keeping your blood sugars at recommended levels, so these things are the priority over eliminating any level of ketosis.
posted by treehorn+bunny at 4:59 PM on March 4, 2016 [1 favorite]


Ketones are always monitored in pregnancy because every prenatal appointment they check a urinalysis, which checks for ketonuria.

I stand corrected; it is possible that the OB-gyn or the consulting midwife may have done that. There was a division of labour between them and our diabetes team. (And in any case, I'm in Holland and practices may vary.) In that case I should have said that it's not something we tested for. OP, consider that part of my previous reply as irrelevant or possibly, wrt your case, just wrong.

posted by sively at 11:06 PM on March 4, 2016


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