evidence: The only time they aren't recommended is if your waters have broken but you haven't gone into labour, but once in labour they're great for pain relief. [...] Bath products cannot harm your baby as it sits high in the womb behind the cervix, and is protected by amniotic fluid. It is thought that some aromatic oils, such as jasmine and clary sage, can cause the womb to contract so use these products in moderation. Although most bath products cannot harm your baby, it’s probably wise to keep your bath as simple as possible. During pregnancy, you're more susceptible to thrush, and some soaps and bubble baths can exacerbate symptoms. So to avoid unnecessary itching, it’s probably best to forego that new Lush bath bomb (think of the glitter).