There appears to be limited regulation specifically on foods for use by pregnant or lactating women. Countries that do have such legislation include Japan, Russia and Korea. Such foods tend to fall into the category of 'Food for Special Dietary Uses'.
Food for pregnant or lactating women refers to a product manufactured or processed to provide whole or parts of a meal to pregnant or lactating women, who have different nutritive requirements due to pregnancy, delivery, or lactation(1)
(1) Article 5. Standards and Specifications for Each Food Product ex. Korean Food Standards.