Hello. Thanks for writing to us at healthcaremagic This seems like a Fungal Infection/ Tinea Cruris; patches of Tinea usually start as bumps which tend to expand and coalesce to form a peripheral raised margin with central clearing. Itching is common in fungal infections. The location too seems to suggest that it is most likely a fungal infection; fungal infections are common at sites such as waist and pubic region. I would suggest you to use an OTC topical antifungal clotrimazole 1% cream, twice daily for 4-6 weeks, regularly. Oral antifungals may be avoided during pregnancy. An oral antihistamine e.g hydroxyzine is safe in pregnancy and can be taken if itching is bothersome. Regards