Hello thank you for trusting HCM Dear thread worm s infection come through eggs transmission through fecoral route. thread worm s lay eggs around perianal region these eggs may enter into finger nails. so if not maintaining proper hygiene they may enter your food while eating cause infection. don t worry they can t infect your baby. but keep maintain good hygiene,wash hands every time using toilet.chenge bedsheets weekly once. drugs like mebendazole also used but during pregnancy uses outweigh risks. every drug has its own side-effects on fetus need fetal monitoring. want to take drugs take under care of your doctor.maintain hygeine itself cure infection from some patients. I think I answered to your question if you have more questions feel free to ask. take care