France is the country of Europe where the prevalence of pregnant women smokers is the highest (35.9% before pregnancy and in the 3rd quarter 21.8% in 2008).

In the investigator's country, among the smokers of early pregnancy with the usual care, only 30% manage to stop during pregnancy.

Maternal smoking during pregnancy is a clearly identified risk factor for the course of pregnancy and the unborn child.

The measurement of carbon monoxide (CO) expired in pregnancy monitoring consultation is part of the recommendations of the consensus conference "Pregnancy and Tobacco" (ANAES, October 2004) and the parliamentary report on smoking by JL Touraine and D. Jacquat (Feb 2012). However, this recommendation has not entered the current practice. The research aims to justify the clinical relevance of this recommendation by demonstrating the positive impact of expired CO measurement on the rate of discontinuation during pregnancy.

Inclusion Criteria :

Group of smoking pregnant women (N = 600):

• Pregnant women declaring themselves smokers (at least one cigarette a day).
• Aged at least 18 years old.
• Consultant at Limoges University Hospital before the 24th week of amenorrhea.
• Desiring to be followed for their entire pregnancy at the Children's.
• Desiring to give birth at the Children's.
• Accepting to participate in the study

Group of strictly non-smoking pregnant women (N = 50):

• Pregnant women :

  • Declaring not to be a smoker (to have been totally weaned for more than one year and to have smoked less than 100 cigarettes in her lifetime) before the beginning of the current pregnancy, and
  • Whose partner and family do not smoke, and
  • Not significantly exposed to tobacco (in their professional environment in particular), and
  • With a CO measurement expired <3 ppm.

• Aged at least 18 years old.

• Consultant at Limoges University Hospital before the 24th SA.

• Desiring to be followed for all their pregnancy and give birth at the Children's Hospital of Limoges.

• Accepting to participate in the study.

Exclusion Criteria :

Group of smoking pregnant women (N = 600) :

• Women with the following social and / or legal criteria: guardianship, curatorship, safeguard of justice.
• Women unable to understand the objectives of the study and the constraints of the protocol.

Group of strictly non-smoking pregnant women (N = 50) :

• Women with the following social and / or legal criteria: guardianship, curatorship, safeguard of justice.
• Women unable to understand the objectives of the study and the constraints of the protocol.
• Women with high blood pressure
• Diabetic woman
• Woman with hypothyroidism