Fasting is a feature of many of the world’s religions, such as Islam, Christianity and Judaism. It’s been practised for many generations, including during pregnancy and breastfeeding.

Religions that promote fasting have rules to ensure you fast safely during pregnancy and breastfeeding. Australian health authorities also have helpful guidelines regarding how to fast safely.

What is fasting?

Fasting is when you don’t eat or drink anything for a certain period of time. Depending on your religion, it may be for certain days of the year or for a whole month.

Which religions require fasting, and for how long?

The Islamic religion requires every healthy adult to fast from sunrise to sunset during the 9th month of the year, known as Ramadan. As the month of Ramadan is set by the lunar calendar, the solar (Gregorian) date will change from year to year. The length of the fast varies between 11 and 19 hours each day, depending on whether Ramadan happens in the winter or summer.

Judaism has several major and minor fast days, and the most strictly observed is an almost 25-hour fast called Yom Kippur. Eating and drinking is forbidden from sundown on the eve of Yom Kippur, until the next sundown.

Christians usually fast on Ash Wednesday and Good Friday and usually don’t consume meat on any Friday of the year. When you are fasting, you are allowed one full-size meal during the 24-hour period and 2 smaller snacks throughout the day.

During the 6-week period of Lent, many Christians abstain from a luxury or certain food of their choice.

Is religious fasting still mandatory for pregnant women?

A Muslim woman who is pregnant or breastfeeding during the month of Ramadan is exempt from fasting. However, if she is feeling healthy, she may choose to fast.

Christians who are pregnant or breastfeeding are also exempt from fasting on Ash Wednesday and Good Friday. But they can if they are healthy and choose to do so.

The different Jewish fasting days pose different levels of stringencies. For the 3 less strict fasting days, pregnant and breastfeeding women are exempt from fasting.

On the 2 more stringent fast days (Yom Kippur and Tisha Ba’av), observant pregnant and breastfeeding women who are otherwise healthy can consider fasting.

You should talk to your doctor or midwife before you fast. There are many religiously-observant GPs (general practitioners) in Australia who can explain any risks associated with fasting – while being sensitive to your religious or spiritual needs.

How do I fast safely while pregnant or breastfeeding?

If you are pregnant and intend to fast, it’s best to plan ahead.

During Ramadan, in the hours where it is permissible to eat – or throughout the day before the Jewish Yom Kippur fast – drink plenty of water to stay hydrated throughout the fast. This is especially important if Ramadan falls during the summer when the fast is longer and the weather is hotter.

Christians can still drink during their fasting days, so water, juice, tea and coffee is allowed.

Throughout pregnancy and breastfeeding it is important to eat nutritious food as part of a well-balanced diet, especially before and after a fast.

When should I consider not fasting?

It is not recommended to fast for Ramadan if you are pregnant in your second or third trimester.

While fasting on Yom Kippur is required by Jewish law even while pregnant or breastfeeding, a woman who goes into labour on Yom Kippur should not continue her fast. A woman who has given birth up to 3 days before Yom Kippur should also not fast.

During Lent, pregnant and breastfeeding women are exempt, so unless you choose to fast, you don’t have to.

Can fasting harm my baby?

While research on the effects of fasting on pregnancy is limited, studies have shown that fasting during pregnancy does not affect the baby’s birth weight or increase the chance of a preterm birth.

Does fasting affect breastfeeding?

If you are breastfeeding and planning to fast, drink extra fluids in the days leading up to, and during, the fast – if possible. Try to minimise physical activities and exposure to heat as much as possible while fasting.

Fasting while breastfeeding is not likely to cause any harm to your baby, and you can continue to breastfeed as usual on the day of the fast. It’s important to breastfeed as you usually would to keep your baby hydrated. You can check your baby’s hydration by monitoring their poos and wees and comparing it to a usual day. If you are concerned about your baby’s hydration, speak to a healthcare professional.

You may find that for the next day or so after the fast, your baby may seem hungrier and want to feed more often. This is normal and you will settle back in to your usual feeding routine in a few days.

Where can I get more information about fasting?

Every woman is different, and the decision to fast while pregnant or breastfeeding is an individual one.

If you are concerned about your ability to fast while pregnant or breastfeeding, seek advice from a trusted healthcare professional (such as your doctor, midwife or lactation professional).

You can also seek advice from your religious authority. Consider speaking to a doctor who shares your religious heritage.

Muslim women with questions on Islamic law can visit Muslim Women Australia. You can also contact the United Muslims Australia's Social Services Division.

For advice on Jewish observance, pregnancy, breastfeeding and fasting, visit Nishmat, an internationally-recognised institute for women’s health and Jewish law, run by women.

Catholics can contact the Catholic Church in Australia if you have any questions about Lent.