Highly rated supplement to provide nutritional support for your dog during pregnancy: 365 day guarantee; if you are not happy with our prenatal dog vitamins, simply contact us for a full refund; we want you to be completely satisfied with our premium soft chews; as the energy requirements of a pregnant dog will increase 1.25 - 1.5-fold after the 40th day of gestation, our vitamins for pregnant dogs can help your pet get sufficient amounts of the nutrients they need Support normal fetal development and sufficient milk production: Nutrition Strength's premium prenatal dog vitamins help to ensure that your pet gets sufficient amounts of folic acid for pregnant dogs, a B vitamin which may help prevent certain birth defects; during pregnancy and when breastfeeding, your dog needs about 50 percent more folic acid than before it; as it is difficult to get this amount from foods alone, your pet may need to take supplemental folic acid Promote healthy brain development in puppies: folic acid, iron, zinc and iodine help to support the proper development of the puppies' central nervous system and vision; iron is vital for puppies' growth and brain development; during pregnancy, the amount of blood in the mother's body increases, so she needs more of it, both for herself and for the growing babies; zinc has been shown to be essential during pregnancy for adequate placental development and maternal blood pressure adaptations