Is being in ketosis safe during pregnancy?



Can hormones and toxins get released into the breastmilk when doing keto and intermittent fasting? Is the combination of bioidentical hormones, keto and intermittent fasting safe? Is keto the best approach to pregnancy for an obese person? And, is ketosis safe in pregnancy?

Get the answers to these questions in this week’s Q&A with fertility specialist Dr. Fox:

Fat stores releasing to breastmilk?

I am doing extended breastfeeding (very high-fat content milk), and also LCHF/IF. My concern is that as I am burning fat, the hormones and toxins being released are releasing into the breastmilk fats. Is this something to be concerned about? Is it possible to schedule my fast so that those toxins etc aren’t released into milk? How dangerous is it for little ones to get the estrogens in milk?


Dr. Fox:

I would not worry about mobilizing fat affecting your milk in an adverse way. Your stored fats are normal metabolic fats and can be utilized for fuel in your system as well as other functions for fats in your system. Estrogen is always present to some degree in breastfeeding women and is normal. The only thing I would recommend against would be intermittent fasting that might produce a stress response. These hormonal reactions could adversely affect the breast milk. There will be plenty of time to be more aggressive with nutrition after breastfeeding.

Best of luck, Beth.


Bioidentical hormones + keto + IF

I am a 53-year-old woman who’s been happily taking bioidentical hormones for menopause symptoms for four years (mostly hot flashes).

OK to do keto and IF? Should I try to wean off the bioidentical hormones?

I have a normal BMI, but it’s creeping up. I’m used to carrying my weight around my hips and thighs, but since menopause, my small waist has been expanding no matter what I do. I exercise five days a week (swim HIIT and stationery bike HIIT).


Dr. Fox:

I definitely would not discontinue hormone therapy. Estrogen normalizes metabolism and lack of estrogen will increase dysfunction and weight gain. My concern for you would be that the treatment you are on is not adequate. You should have your estradiol checked and adjust levels to at least 80 up to 200. You should work with your doctor to regulate this.

Most of the time in hormone replacement situations, hormone levels are not checked and the endpoint is symptoms. Vasomotor symptoms go away with very low doses of estrogen, but your metabolic system requires more estrogen to be fully normal. Bioidentical is fine as long as you are being treated with estradiol as the primary estrogen hormone. I would decrease the aerobics and change to walking and some light muscle strengthening exercises. I’ve reviewed exercise and its stress reaction being counterproductive in numerous other posts.

Best of luck.

Is being keto sufficient for low risk pregnancy?

Suppose we are talking about a woman who is level one obese, in her thirties and wants to become pregnant but is worried about a family history of diabetes. Would you encourage such a person to conceive (that being in ketosis would protect the child) or is it wiser for such a person to drop to a BMI that is “overweight” rather than “obese level 1”?

This is information-gathering, not direct advise.


Dr. Fox:

I encourage all women to pursue a ketogenic approach to fertility and pregnancy. Yes, ideally weight loss would be a positive before the pregnancy starts in order to reduce insulin resistance. This will ultimately improve the overall pregnancy. The reality though, is soon after one starts the ketogenic approach, metabolism improves dramatically. Therefore a month or two into the process, metabolism might be 80% better. So if timing would dictate an earlier trial of pregnancy, you will still be very healthy proceeding with pregnancy once you are keto adapted.

Best of luck, Betul!

Justifying ketosis in pregnancy

Dr. Fox —

I have been keto for about 15 months. I am planning to have a baby soon. My family is extremely concerned about me staying keto during pregnancy. They sent me the mouse study which showed potential organ damage to baby mice whose mothers were in ketosis during pregnancy.

Are there any studies or other materials I can send them to make them feel at ease?

I have no fertility issues and am at normal weight. Considering there are no human studies showing ketosis is safe during pregnancy, would it be prudent to err on the side of caution and eat higher carbs while pregnant? My family says I am gambling with the health of my baby.


Dr. Fox:

I think the article on this site regarding ketosis in pregnancy is excellent and provides the best answer to this question. Any time in medicine when there is no research to go on regarding a particular question, one must rely on “expert” opinions. Many of those are expressed in the referenced article, including mine. I have been observing this nutritional approach in pregnancy since 2004. There have been no adverse outcomes and universal improvement in maternal/fetal health. This includes one of our physicians and one nurse practitioner in our practice who pursued this approach given their knowledge on the subject. As stated elsewhere, the caveman did not eat carbohydrates, especially ones in the northern latitudes. If ketosis in pregnancy were bad we wouldn’t be here.

I would turn the entire story around and view it the opposite way. Every woman who is eating carbohydrates is exposing their child to the ravages of hypoglycemia multiple times per day. This life threatening stress signal is characterized by massive increases in adrenaline and cortisol. Insulin elevations are causing increases in male hormones that will affect both male and female fetuses’ brain development in negative ways. High blood sugar from carbs will cause insulin responses in babies exposing their metabolism to the litany of ravaging negative effects. One of these factors is the “signal” that stimulates a genetic change in metabolism resulting in abnormal metabolism in adults resulting in all the chronic diseases our modern population suffers from. In summary, I would characterize carbohydrates as a metabolic poison and that ketogenic nutrition is the only way to prevent the above. How’s that for ammunition? Good luck.

I think the recommendation to tell your doctor you are eliminating sugar and starches and eating whole foods instead of using the word ketosis is a good one. When one tests positive for ketones on the urine, the discussion will have to happen. Nutritional ketosis versus diabetic ketoacidosis is what needs to be emphasized. For ?’s refer your physician to me. I am happy to have a dialog with them regarding this issue. In the end, you are in charge of what nutrition your pregnancy and baby enjoys. Rest assured that all my observations and those of others indicate complete safety of this approach.

Best of luck!

Oh, one other thing, if you decide to pursue a ketogenic approach in pregnancy, you should write about it to add to the global experience. The data builds one story at a time at this point.

More questions and answers

Questions and answers about low carb

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