Generally, women are told to avoid consuming large amounts of Liver during pregnancy because it is high in Vitamin A Retinol. We're advised against consuming too much Vitamin A during pregnancy, but certainly not to avoid it all together.  Vitamin A is critical for the healthy development of the fetus, such as the development of many organs including the eyes, lungs, heart and kidneys. Vitamin A deficiency poses a risk to both Mother and Baby
For pregnant women aged 19 - 30 the Recommended Dietary Intake of Vitamin A during pregnancy is 800 mcg per day, and the Upper Level of Intake is 3,000 mcg per day. Those levels are slightly higher than those of a woman of the same age who is not pregnant. You can see those recommendations and other information about Vitamin A here.
One 7.5 g serve of The Mothers Blend contains a very small amount of Liver. The Vitamin A delivered in one serve is 630 mcg - this makes up around 78% of the RDI. As always, please consult your preferred practitioner for complete and personalised advice around this topic.