No human studies to date have evaluated the safety of supplementation with creatine in women during pregnancy. However, studies in rodents suggest that supplemental creatine may not only be safe, but may also have positive effects on birth outcomes.
For example, in one study conducted in mice, maternal supplementation with creatine from the midpoint of pregnancy until birth increased the creatine content of the placenta (+105%) and of some of the fetal tissues, including the brain (+3.6%), heart (+14%), kidney (+22%), and liver (+37%).[1] The increased concentration of creatine in the brain of the fetus before birth may protect the fetus from damage associated with low oxygen availability, such as during a Cesarean section.[2] Protective effects have also been observed in the offspring’s diaphragm (through preserved muscle fiber size),[3] kidneys,[4] and neural tissue (due to less oxidation in the brain and less cellular apoptosis).[5]
Importantly, maternal supplementation with creatine (again, in mice) does not seem to affect the creatine transporter or the enzymes responsible for creatine synthesis in the newborn, which suggests that the capacity for creatine synthesis in the newborn mouse is not altered.[6]