If you are pregnant and have grey nails, it is advisable to observe first, or you can consider applying some antifungal creams topically, but the effect of this is very slight. It is a very difficult disease to treat, usually using antifungal oral medication, like the more common oral medication is terbinafine, this drug needs to be taken for 6-12 weeks; if it is itraconazole is generally taken orally for a week and stop three weeks, so 3-4 consecutive courses of treatment that is more than 3-4 months. The actual fungal drugs are not only toxic to the liver, but they also have side effects on the liver, so the antifungal drugs can only be taken if the liver function is normal. The actual fact is that you can only consider local topical medication when you have grey nails, but you can’t take oral medication until after you are pregnant or breastfeeding.