Thyroid Function Throughout Pregnancy With and Without Iodine Supplementation

The 50 women will be follow up with a supplémentation iodized by vitamins of pregnancy strengthened in iodin everything in the course of the pregnancy and during the 3 months post partum (Oligobs Maxiode, 150 mcg / of iodizes, is 2cp a day)

50 women will be studied in the absence of iodized supplémentation(natural history of function thyroïdienne in the course of the pregnancy and in the post partum)