Editing Development of the human body (section)

===Maternal influences===
{{See also|Placenta}}
The fetus and embryo develop within the [[uterus]], an organ that sits within the pelvis of the [[mother]]. The process the mother experiences whilst carrying the fetus or embryo is referred to as [[pregnancy]]. The [[placenta]] connects the developing [[fetus]] to the [[Uterus|uterine]] wall to allow nutrient uptake, thermo-regulation, waste elimination, and gas exchange via the mother's blood supply; to fight against internal infection; and to produce hormones which support pregnancy. The placenta provides oxygen and nutrients to growing fetuses and removes waste products from the fetus' blood. The placenta attaches to the wall of the uterus, and the fetus' [[umbilical cord]] develops from the placenta. These organs connect the mother and the fetus.  Placentas are a defining characteristic of [[placental mammal]]s, but are also found in [[marsupials]] and some non-mammals with varying levels of development.<ref name="Pou92">Pough ''et al.'' 1992. Herpetology: Third Edition. Pearson Prentice Hall:Pearson Education, Inc., 2002.</ref> The [[Homology (biology)|homology]] of such structures in various [[Viviparity|viviparous organisms]] is debatable, and in invertebrates such as [[Arthropod]]a, is [[Analogy (biology)|analogous]] at best.