Hi, I'm 8 weeks pregnant and I have a probiotic yoghurt every day. My friend saw me drinking one at work and said that I shouldn't be having them because I'm pregnant. Is that true?

Probiotics are live micro-organisms (in most cases, bacteria) that are similar to beneficial micro-organisms found normally in the human gut. They are also called "friendly bacteria" or "good bacteria". Healthy bacteria are part of our immune system and help to prevent infections. In the gut they play a particularly important role. Our so-called friendly bacteria break down food we eat to provide a source of energy for the cells that line the gut.

Probiotics are available in foods and supplements. Examples of foods containing probiotics are yogurt, fermented and unfermented milk, miso, tempeh, and some juices and soya drinks. In probiotic foods and supplements, the bacteria may be present naturally, or added during manufacture.

Probiotics from both natural food sources and supplements are considered safe for healthy pregnant women to use. There is currently no guidance on the quantities of probiotics that are safe, but in 143 studies using different probiotics that included over 7,500 non pregnant participants, no serious adverse effects of probiotics have been reported.