Staring at a positive pregnancy test? Congratulations!
Now it’s time for all the planning — and if you have been following a keto diet, you may be wondering if you can continue eating keto while pregnant.
There’s still a lot we don’t know about keto and pregnancy because there hasn’t been a lot of research on this topic yet, but we’ve compiled this guide to help you make the best decision for your growing family.
What Is the Keto Diet?
Keto is a low-carb, high-fat, moderate-protein diet. Generally, the macronutrient breakdown is roughly 5% carbohydrate, 20-25% protein, and 65-70% fat.
Severely restricting carb intake will eventually cause your body to enter a state of ketosis, where it is burning fat as its primary source of fuel rather than carbs (*).
There are several therapeutic benefits to ketosis. In fact, a ketogenic diet (one that induces ketosis) is a very effective strategy to help manage epilepsy (*).
Additionally, keto has proven to be extremely helpful for weight loss and blood glucose management. Many people have successfully lost weight with keto, and it’s also a great option for improving glycemic control in people with type 2 diabetes (*).
Keto During Pregnancy: Is It Possible?
Pregnancy is a unique time. The body undergoes extensive changes accompanied by huge shifts in hormones as the blood supply increases, the muscles and joints all become more relaxed, and the body grows both the placenta (a new organ) and a baby.
If you followed a keto diet before pregnancy, or if you’ve recently heard about keto, you may be wondering if it’s possible to follow while pregnant.
The answer, unfortunately, is: maybe.
On online message boards, you can find many keto pregnancy success stories. You’ll also find your fair share of stories of women who just couldn’t do keto while they were pregnant.
One major barrier to following the keto diet during pregnancy is nausea and food aversions.
Many pregnant women develop strong aversions to meat, eggs, and cheese, which makes it very difficult to maintain a keto diet. During the first trimester, when these food aversions are the worst, many women choose to temporarily increase their carb intake.
However, it also appears that it’s easier for pregnant women to enter ketosis. Therefore, many women find that they can increase their carb intake slightly during pregnancy while remaining in ketosis (*).
Is It Safe to Follow a Ketogenic Diet During Pregnancy?
Now for the even bigger question: is it safe to follow a ketogenic diet while pregnant? The answer is complicated.
Fortunately, there are several research studies we can look to for guidance.
A handful of mouse studies have noted that exposure to ketones or following a ketogenic diet causes changes to embryo development. This suggests potential to cause birth defects (*)(*)(*).
However, another found that exposure to a ketogenic diet increased sociability and reduced depression-like symptoms in the offspring of the ketogenic diet-fed mice. This suggests that exposure to ketones may actually help with neurodevelopment (*).
However, it’s important to remember that these studies were done in mice, so the results should be taken with a massive grain of salt.
There is also some extremely limited evidence available on the safety of ketogenic diets in women.
In a case report detailing two “keto pregnancies,” researchers found that one had no complications, but in the other the infant was born with some ear abnormalities. The cause of these abnormalities was not determined, so they weren’t necessarily related to keto (*).
Much of the risk in pregnancy lies in ketoacidosis, which is a serious medical condition characterized by high blood glucose levels and high ketone levels. It’s rare for the keto diet to induce ketone levels high enough to cause ketoacidosis, but still possible (*)(*).
Overall, it’s best to speak with your OB/GYN, midwife, or pregnancy healthcare team about the best diet approach for your pregnancy.
Potential Benefits of the Keto Diet for Pregnant Women
Here are some of the potential benefits of keto while pregnant.
Epilepsy Management
In the case report we referenced above, both of these women were instructed to follow a ketogenic diet to help manage seizure disorders while they were pregnant (*).
This is one case in which women may be urged to stick to a ketogenic diet throughout their pregnancy, since many anti-seizure medications shouldn’t be used during pregnancy (*).
Glycemic Control
For pregnant women with diabetes, including those who are diagnosed with gestational diabetes during their pregnancy, keto may help to control blood sugar levels.
Healthy Weight Gain
Following a keto diet may also help prevent excessive weight gain during pregnancy, since it helps to regulate appetite and is mostly composed of filling protein, fat, and fiber-rich foods.
Potential Risks of the Keto Diet While Pregnant
Here are some of the potential risks of keto while pregnant.
Birth Defects
In animal models, exposure to ketones or following a ketogenic diet while pregnant has been associated with fetal developmental abnormalities.
Therefore, it is possible that keto could cause birth defects. However, there’s not a lot of evidence for this in humans.
Weight Loss
One of the benefits of keto for weight loss is that it helps control your appetite. Some people almost never feel hungry on keto. However, it’s important to eat consistently while pregnant, and if you don’t often feel hungry this could actually lead to unwanted weight loss.
Ketoacidosis
Paired with extended fasting, keto has been shown to cause ketoacidosis — a serious medical condition — in some people. Pregnant women may be at an increased risk of this as it’s easier for pregnant women to both enter ketosis and become dehydrated than the general population (*)(*)(*).
It’s extremely important to strictly avoid fasting while pregnant.
Failing Oral Glucose Tolerance Test
The oral glucose tolerance test (OGTT) is a screener for gestational diabetes that involves taking a large dose of glucose and then having your blood glucose levels checked.
Many women who eat keto during pregnancy report failing this test despite not having gestational diabetes when further testing is done.
This is because, after the body adjusts to keto, eating a large amount of glucose (sugar) all at once causes blood sugar levels to skyrocket.
According to online message boards, many women choose to eat roughly 150 grams of carbs per day in the week or two leading up to their OGTT so that the results of the test will be more accurate.
Are There Any Risks of Ketoacidosis During Pregnancy?
Yes, ketoacidosis during pregnancy is a very serious condition that can threaten the life of both mother and infant (11).
This condition mostly occurs in people with diabetes — including gestational diabetes.
However, the keto diet has lead to ketoacidosis in some cases. Paired with prolonged fasting, it could cause a condition called starvation ketoacidosis (*).
Are There Any Alternatives to the Keto Diet That Are Safer for Pregnancy?
Overall, it may be best for pregnant women to adopt a more flexible low carb approach throughout their pregnancies. A carbohydrate goal of anywhere from 75-150 grams per day may be a good range for most pregnant women, unless they’ve been otherwise instructed by their healthcare provider.
This still provides the benefits of low-carb eating, but without the potential risks associated with ketogenic eating while pregnant.
You can choose to add small quantities of healthy, high-quality carbs, like rice, fruit, oats, plain whole greek yogurt, and potatoes to help you reach this carb goal.
Additionally, be sure to avoid fasting while pregnant.
The Bottom Line
Eating keto during pregnancy may have some risks, but there are several reports online of women following a keto diet and having a perfectly successful pregnancy and a healthy baby.
Still, a more flexible low-carb approach may be the best choice because it provides similar benefits without the potential risks.
However, it’s important to speak with your pregnancy healthcare team about the best pregnancy diet for you.