Intermittent Fasting While Pregnant: Is It Safe?

Medically reviewed by Maria Sarino, MD FACT CHECKED

For most women, pregnancy is a beautiful period of transition. Women often gain weight during pregnancy, which is quite healthy and natural.

As your baby bulge grows in size, your body is going to have many varied demands. Also, you shall need the requirement of many different sizes of what you wear.

However, few women gain weight more quickly than the rest. If you acquired a lot of weight than you required during your pregnancy period, you might be seeking ways to lose that extra weight.

Fasting intermittently has become a popular method of weight loss for both women and men. Perhaps you have done this before you became pregnant and currently, you are concerned about the impact of it on your baby.

You might also be looking at intermittent fasting research for different reasons. Make sure to keep in mind that most doctors shall not allow breastfeeding mothers or pregnant women to fast.

Whatever it is that has intrigued your desire in fasting intermittently while you are pregnant, there are a few factors to consider.

In this article, we will be looking at what intermittent fasting is, should a pregnant woman do intermittent fasting, and a lot more.

Intermittent Fating While Pregnant: Is It Safe?

Fasting has unknown effects on your body during your pregnancy. How fasting affects you might differ from how it affects someone else.

Therefore, the American College of Obstetricians and Gynecologists suggests that you should collaborate with your healthcare physician and design a personalized weight increase meal plan based on your overall health and BMI.

For women with BMIs ranging from 18.6 to 24.8, this usually entails adding 26 to 36 pounds by drinking lots of water and eating a well-balanced meal of healthy foods.

Those who are heavier might need to put restrictions on their weight gain with the help of a doctor and also carefully monitor their baby’s progress.

It is never suggested that pregnant women should engage in intermittent fasting. If you are thinking about fasting intermittently while pregnant, here are some considerations to keep in mind:

  • First Trimester 

    During their first trimester, most women could develop a food aversion and feel nausea. This usually occurs between 6 and 8 weeks.

    This occurs as the body is beginning to prepare for growing your baby and eventually giving birth as your hormones change.

    During the 1st trimester, your insulin resistance improves for a certain period and your sugar levels tend to drop a little.Your pancreas also begins to develop.

    Therefore, your body produces more insulin. It has also been shown that ladies having type one diabetes who do not make insulin could see an increase in their levels of insulin.

    The growth of beta cells during pregnancy has been suggested as a possible cause. This might cause a temporary increase in insulin production.

    You are going to be hungry at this point, however, due to your sickness and food aversion, you might not feel like eating a lot.If you are going to try eating an enormous meal at once, you might end up throwing up later.

    Small meals or snacks whenever you feel hungry are your sole option for satisfying your hunger without becoming ill.

    It is critical that you eat healthily during your 1st trimester, especially if you are having dietary aversions which prevent you from eating fat or protein at certain times.

    It is possible that forcing the body too much to fast during these times might make you to feel worse.

    Only by eating when you are hungry shall you be able to satisfy your appetite without being sick. Intermittent fasting is quite impossible at phases like this.
  • Second Trimester

    Some women’s food aversions and sicknesses could subside during this period, which allows them to resume an eating schedule daily.

    However, make sure to keep in mind that this does not apply to everyone. Pregnant females should concentrate on satisfying their nutritional requirements.

    If you are trying to fast regularly, you shall have less opportunity in getting those nutrients. Some women might feel well if they eat 2 meals per day at this time.

    You should not have to pressurize your body by eating more. There is not anything wrong with this pattern as long as it is the one that your body naturally follows.

    However, you should not force yourself to stop eating when pregnant. Instead, you should listen to it.

    If you feel hungry, eat more. Make sure to keep in mind that your diet plan should be well-balanced.

  • Third Trimester

    Trying to eat your meal inside a certain period throughout your 3rd trimester is going to be the most difficult.

    Your baby is growing at this point in your pregnancy. So, your tummy shall be quite large. Therefore, your stomach might get constricted.

    Your body is going to require 2400 to 2800 calories every day throughout your third trimester. You would not be able to consume so many calories in the tiny window you might have when breaking fast.

    You would not be able for digesting your food as your stomach could become too constricted. During pregnancy in a later stage, your body shall require 75 percent more protein.

    You are in the process of creating another human in your uterus. During this pregnancy phase, insulin resistance is also very high.

    For females in their 3rd trimester, having tiny meals in the day is the healthiest option. It is not a good idea for trying intermittent fasting at this point.

    Discuss the ideal meal plan for you in your 3rd trimester with your doctor. This matter has been acknowledged in this government study as well.

Risks Of Intermittent Fasting During Pregnancy

While the long-term results are unknown, researchers studied how women’s intermittent fasting influences fetal breathing and certain factors.

When women’s glucose levels are low due to fasting, it takes much longer for them to detect fetal movements.

Low fetal movement is often regarded as a warning indicator that should be taken carefully, especially as your due date approaches.

Within one to two hours, your baby should produce ten movements. You should also be able to feel ten movements within 30 minutes.

It could be tough to get proper nourishment quantities when you restrict your eating to specific times in a day.

This is made more difficult as your baby is also drawing on your nutritional reserves. Iron deficiency like anemia is becoming more common among pregnant women.

When a baby does not acquire enough iron, especially during its third trimester, the baby is more likely to develop anemia before reaching its first birthday.

However, you could reduce intermittent fasting side effects by improving your nutritional intake.


Intermittent fasting during your pregnancy is usually not a good idea, especially if you have never attempted it before.

The good news is that pregnancy does not endure indefinitely, and you could use this eating habit for losing weight after you have given birth. However, if you are breastfeeding, see your doctor.

And, if you are feeling overwhelmed, do not be afraid in seeking assistance. At each of your prenatal sessions, your healthcare practitioner is going to keep track of your weight.

Discuss the concerns about you gaining a lot of weight and see if they have any suggestions to help you in reducing your weight if necessary in a way that keeps you and your baby healthy.