Is intermittent fasting safe during pregnancy?
For healthy pregnant women, fasting does not appear to increase major risks such as preterm birth or low birth weight, but fatigue and dehydration are real complaints. If you have diabetes or are early in your pregnancy, discuss fasting with your doctor first.
Fasting during pregnancy reduces average birth weight by approximately 94 grams. This is statistically measurable, but clinically negligibly small. The risk of a baby being born genuinely underweight, below 2,500 grams, does not increase. Preterm birth also does not occur more frequently in women who fast.
There is one exception that deserves attention: fasting specifically in the first trimester appears, in one study, to be associated with a much larger drop in birth weight, namely an average of 353 grams. This finding stands alone and has not yet been confirmed in other studies, but it is a reason for extra caution early in pregnancy. The same study found that a higher-fat diet outside fasting hours may have a protective effect on birth weight, although that too is not yet well substantiated.
For the mother herself, the most clearly documented risks are fatigue and dehydration. In addition, there are preliminary indications that fasting may affect the results of prenatal check-ups: reduced fetal movement, reduced amniotic fluid volume, and lower scores on the biophysical profile. These findings come from a limited number of studies and require confirmation.
For pregnant women with diabetes, fasting is genuinely inadvisable. During fasting hours, blood sugar drops to dangerous levels, while after breaking the fast it rises sharply. Physicians currently explicitly advise pregnant women with diabetes against fasting.
Too little is known about the long-term health consequences for the child. Studies examining this are of low quality, and firm conclusions cannot be drawn. Always discuss any doubts about fasting during pregnancy with your midwife or doctor.
This answer is based on multiple summaries of studies, including a review of dozens of individual studies and studies involving thousands of pregnancies. In every case the research is observational: no study was able to directly establish cause and effect, because women were not randomly assigned to a fasting or non-fasting group. The finding regarding the first trimester comes from a single study, and the findings on diabetes come from only five small studies. The researchers rated the quality of the evidence on long-term outcomes for the child as low to very low.
What does pregnancy do to your hormone balance in the long run?
Pregnancy and breastfeeding bring measurable, sometimes long-lasting hormonal changes, of which the genital and urinary complaints caused by oestrogen loss are the best documented. Knowing what to expect makes it easier to talk about these issues and seek help.
Is hormone therapy during menopause safe and worthwhile?
Hormone therapy works very well against hot flushes and protects bones, but at the same time raises the risk of stroke and blood clots. Whether it is worthwhile and safe for you depends on your personal risk profile, your symptoms, and the form and duration of use: discuss this with your doctor.
What does chronic sleep deprivation do to your fertility?
Chronic sleep deprivation and frequent insomnia have been linked in several large studies to a lower chance of conception and more reproductive problems. If you want to become pregnant, getting regular and sufficient sleep is a concrete starting point, even though causality has not yet been definitively proven.
Can you preserve your fertility as a woman for longer through your lifestyle?
Studies show that a healthy weight is measurably linked to better fertility. Whether changing your lifestyle actively preserves egg supply for longer is not yet known with certainty.
Is intermittent fasting safe if you have type 2 diabetes?
Intermittent fasting can be safe in type 2 diabetes, but only if you do this in consultation with your doctor, because your medication will almost always need to be adjusted to prevent blood sugar from dropping too low.
Does fasting or intermittent fasting help prevent cancer?
Animal research into fasting and calorie restriction shows encouraging signals. In people, results from small studies are mixed.