вот британские рекомендации для беременных: наверное и в РФ похожие есть, но к вам их не применили:
Non-anaemic women identified to be at increased risk of iron deficiency
should have a
serum ferritin checked early in pregnancy and be offered
oral supplements if
ferritin is <30 ug/l
Women with established iron deficiency anaemia should be given 100-
200mg elemental iron daily.
https://forums.rusmedserv.com/showthread.php?t=232894