Eddie, it is not the Estrogen & Progesterone, even though they do increase greatly when a woman is pregnant.

It is called "Early Pregnancy factor" that pregnant women make. It is also found on the entrance to the uterus.

A pregnant female makes this to protect the baby from being attacked by the mother's normal autoimmune system. The baby is alien to the mother's body, like heart or liver transplant would be, so the pregnant body makes it's own anti-rejection hormone to protect the baby from being rejected.

This can't be bottled or made (maybe female animal to female animal, ect.). It is only made by a mother during pregnancy. Rodents make it too. See below.

It helps women because it prevents inflammation, and stops the body from attacking the myelin too, so MS is calm during pregnancy in most cases.

http://www.ncbi.nlm.nih.gov/pubmed/14607300

A protective effect of early pregnancy factor on experimental autoimmune encephalomyelitis induced in Lewis rats by inoculation with myelin basic protein.
Harness J, Cavanagh A, Morton H, McCombe P.

Department of Medicine, University of Queensland, Clinical Sciences Building, RoyalBrisbane Hospital, Herston, Queensland 4029, Australia. j.harness@medicine.uq.edu.au

Abstract
Experimental autoimmune encephalomyelitis (EAE) is an organ-specific autoimmune disease characterised by inflammation and demyelination of the central nervous system and is the best available animal model of multiple sclerosis (MS).

see link for more.