Keto and Pregnancy: Are There Any Risks?

There’s no doubt keto can be great for your health. It can help you lose weight, reverse diabetes, and reduce heart disease risk, among so many other things [1].

But what about pregnancy? Can keto help or do the opposite on that front?

If you’re expecting or are planning to conceive, it’s natural that you ask yourself these questions. Pregnancy, childbirth, and breastfeeding are physically demanding, after all, and good nutrition is essential in meeting these demands. As a mom-to-be, you’re also worried about whether keto may impact your growing baby.

To help you in deciding what’s best for you and your baby, here’s what you need to know about keto and pregnancy.

Is Keto Safe During Pregnancy?

The honest answer is, we simply don’t know.

There are no clinical studies looking into keto’s impact on pregnancy outcomes, so nobody can really tell you whether keto is safe or not when it comes to this stage in life.

Lack of research in this area is mainly due to ethical reasons. But as more and more women adopt low-carb living, we’ll probably know more in the future.

A study in mice, however, suggested keto is not safe during pregnancy [2]. When pregnant mice were put on a low-carb diet, the embryos’ organs were either larger or smaller than normal. The study concluded that keto during pregnancy could negatively impact the fetus. But findings from animal studies don’t always apply to humans.

Then there’s research looking at the impact of elevated ketones during pregnancy in mothers with and without gestational diabetes [3, 4]. The general agreement among researchers carrying out these studies is that elevated ketones negatively affect a baby’s development. For example, high blood ketones often correlate with cleft lip and spina bifida. Note that there’s no mention of causation here, just correlation.

But none of these examples look at how the keto diet, in particular, affects pregnant women or their babies. They only show its effects on rodents or the consequences of diabetes during pregnancy — none having much to do with keto and how people follow it.

But there is one case series that could shed some light!

It involves two women put on keto to control their epileptic seizures while pregnant [5]. Epilepsy drugs can harm a developing baby, so it made sense to look into keto as a safer alternative for these women. Turns out, both had fewer seizures thanks to keto and gave birth to healthy babies! Still, the researchers concluded that we need to see more similar studies to check if keto is truly safe for pregnant women.

What About Keto for Gestational Diabetes?

Gestational diabetes (GB), like all types of diabetes, is a condition of carb intolerance.

The first step to treating it is changing your diet. Usually, doctors will recommend cutting carbs to some extent in the management of GB — for example, reducing your intake of refined grains and added sugars.

Since keto is a low-carb diet, you may be wondering if you could manage GB with it. Well, a review of studies looking into low-carb diets for GB mentions that recent evidence shows these diets could help lower blood glucose in moms and birth weight in babies [6].

But keto isn’t your average low-carb diet; keto is a very low-carb diet that puts the body in ketosis. You want to know whether keto specifically can do the trick. Unfortunately — as is usually the case — there are not enough studies to say that, yes, you could successfully treat GD with keto [7].

None of this means keto is no good for GB, though.

Many women have had success with these approaches. Just take for example Carmen Lavoie, Ph.D., and her piece in Canadian Family Physician. There, she details her successful management of GB with a low-carb diet [8]. Thanks to this approach, she was less reliant on insulin shots as a result and had a healthy pregnancy throughout.

Unfortunately, her medical team wasn’t as thrilled. They disagreed with her strongly, believing she was endangering her pregnancy by keeping her blood glucose low and ketones high. She notes, however, that this reaction needs to be questioned considering that many societies (e.g. the Inuit) have had healthy pregnancies despite a diet almost devoid of carbs.

Keto and Fertility

And then there’s also the ongoing debate about keto’s impact on fertility. Does it boost fertility? Does it make it harder to conceive? If you’re trying for a baby, then you likely feel that this definitely concerns you.

It’s true that some women following low-carb diets notice their periods becoming irregular. The most common cause behind this, however, is functional hypothalamic amenorrhea, which is something caused by extreme weight loss or low leptin levels [9]. But this likely won’t happen to you if you follow a balanced low-carb diet and don’t lose too much weight.

On the other hand — if you’re overweight, have polycystic ovary syndrome (PCOS), or diabetes —  then keto can help boost your fertility. It can do so mainly because it lowers insulin, a key driver of these conditions and a cause behind infertility in women [10].

And besides boosting your chances at conception, the weight loss, glycemic control, and low insulin that come with following a keto diet can translate to a healthy pregnancy later on —  even if you discontinue keto.

And as far as male fertility goes, keto can help here as well, especially if low fertility is tied to a man’s metabolic syndrome or being overweight. A report on two overweight men found that going on a keto diet boosted their sperm count by 20-40% and their sperm motility by up to 62% [11]. So, it definitely goes both ways.

Key Takeaways

The keto diet can help improve health. There are countless studies that prove this is the case. However, keto is very much understudied, and nowhere is that more true than where pregnancy is concerned.

Most studies on keto and pregnancy were done in mice, unfortunately. Others were of poor quality. At the end of the day, we know very little about how keto affects women and their babies during pregnancy.

On the other hand, you’ll hear countless anecdotes from women saying they had a healthy pregnancy while following keto. Some even successfully managed GB with a low-carb diet. So, there seems to be plenty of reason for optimism. But until research proves keto is safe for pregnant women and fetuses, we’ll have to wait before we see physicians and health authorities recommending it.

Related: Low Carb or Keto for Kids

References

Weber DD, Aminzadeh-Gohari S, Tulipan J, Catalano L, Feichtinger RG, Kofler B. Ketogenic diet in the treatment of cancer - Where do we stand?. Mol Metab. 2020;33:102-121. doi:10.1016/j.molmet.2019.06.026

Sussman D, van Eede M, Wong MD, Adamson SL, Henkelman M. Effects of a ketogenic diet during pregnancy on embryonic growth in the mouse. BMC Pregnancy Childbirth. 2013;13:109. Published 2013 May 8. doi:10.1186/1471-2393-13-109

Bronisz A, Ozorowski M, Hagner-Derengowska M. Pregnancy Ketonemia and Development of the Fetal Central Nervous System. Int J Endocrinol. 2018;2018:1242901. Published 2018 Jun 4. doi:10.1155/2018/1242901

Qian M, Wu N, Li L, et al. Effect of Elevated Ketone Body on Maternal and Infant Outcome of Pregnant Women with Abnormal Glucose Metabolism During Pregnancy. Diabetes Metab Syndr Obes. 2020;13:4581-4588. Published 2020 Nov 25. doi:10.2147/DMSO.S280851

van der Louw EJ, Williams TJ, Henry-Barron BJ, et al. Ketogenic diet therapy for epilepsy during pregnancy: A case series. Seizure. 2017;45:198-201. doi:10.1016/j.seizure.2016.12.019

Farabi SS, Hernandez TL. Low-Carbohydrate Diets for Gestational Diabetes. Nutrients. 2019;11(8):1737. Published 2019 Jul 27. doi:10.3390/nu11081737

Mahajan A, Donovan LE, Vallee R, Yamamoto JM. Evidenced-Based Nutrition for Gestational Diabetes Mellitus. Curr Diab Rep. 2019;19(10):94. Published 2019 Aug 31. doi:10.1007/s11892-019-1208-4

Lavoie C. Gestational diabetes: poke, pee, and eat your carbs. Can Fam Physician. 2011;57(7):756-e240. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3135431/

Meczekalski B, Katulski K, Czyzyk A, Podfigurna-Stopa A, Maciejewska-Jeske M. Functional hypothalamic amenorrhea and its influence on women's health. J Endocrinol Invest. 2014;37(11):1049-1056. doi:10.1007/s40618-014-0169-3

Silvestris E, Lovero D, Palmirotta R. Nutrition and Female Fertility: An Interdependent Correlation. Front Endocrinol (Lausanne). 2019;10:346. Published 2019 Jun 7. doi:10.3389/fendo.2019.00346

Renck A, Afonso Teixeira T, Risso Pariz J, Barbosa Trarbach E,  Hallak J, Frade Costa EM. Semen quality improvement after weight loss by very low-calorie ketogenic dietary: A report of two cases. Reproductive and Developmental Endocrinology. 2020; 70 EP379. doi: 10.1530/endoabs.70.EP379