I have the same issue. Dr . told me that of course each pregnancy is different and this occurs do to the hormones. :( but in the meantime continue with the vitamins. Good luck :)
I'm a hair stylist and it happens sometimes. Some people get thin hair while pregnant. . Some get thick hair. Have you been to the doc yet? I Would definately get them to check your thyroid level. . It could very well be that. Try not to brush your hair too Much. . Especially when wet. . That's when your hair is at its most fragile point. Is it breaking off or falling out from the root? If it's breaking off you could use anti snap from redken. . That would help.
Are you pregnant now or you already had the baby