In women, tobacco impairs fertility by different mechanisms. Nitric oxide (NO), nicotine and carbon dioxide produced by cigarettes cause hypoxia (poor oxygenation) of the various tissues, which will adversely affect the proper functioning of the various organs (ovaries, uterine tubes, uterus) involved. in the design. Cigarettes also contain toxic substances that can lead to endocrine disruption potentially harmful to fertility. Thus, it is now shown that in women, smoking is responsible:

• ovulation disorders, by alteration of estrogen production by toxic tobacco products (nicotine, tar, etc.)
• a decrease in the number of oocytes and a decrease in ovarian reserve
• a decrease in the ability of the oocytes to be fertilized (by thickening of the zona pellucida of the oocyte)
• a decrease in ciliary mobility (natural movement of the tubes) necessary for the migration of gametes and the egg. The chances of an encounter between the oocyte and the sperm are therefore reduced and the risk of ectopic pregnancy is increased. 20% of GEU would be attributable to smoking (1).
• hypoxia which alters the vascularization of the uterus, which leads to a decrease in the implantation capacity of the embryo in the uterus.

 In the end, smoking is responsible for a drop in female fertility of the order of 10 to 40% depending on the number of cigarettes smoked per day. It also lengthens the conception period from 4 to 6 months, knowing that the more the number of cigarettes smoked, the more this period increases (2).

In men, recent studies have shown that certain substances in cigarette smoke cross the blood-testicular barrier and lead, once in the seminal fluid, to an alteration in spermiological parameters and sperm quality, thereby compromising the chances of pregnancy (3).

Smoking increases the risk of various complications of pregnancy:

• the risk of early miscarriage would be multiplied by 1,5 to 3 times depending on tobacco consumption. For a woman who smokes more than 30 cigarettes per day in early pregnancy, this risk would be multipliedÌ ?? by 5 (4).
• the risk of low implantation of the placenta can be the cause of a troplacental hematoma and bleeding during the third trimester.
• the risk of rupture of membranes before 34 weeks of amenorrhea would be multipliedÌ ?? par 3. It is the leading cause of premature labor in pregnant smokers (5).

Smoking impairs the development of the fetus by various mechanisms, the first being poorer oxygenation. When the expectant mother smokes, her blood takes on carbon monoxide, and the fetus is oxygenated by the mother’s blood; it is therefore directly exposed to this toxic gas. Furthermore, nicotine has a vasoconstrictor effect on the arteries of the placenta and the umbilical artery. The maternal-fetal circulation is therefore less efficient and the fetus less well oxygenated. Finally, the toxic substances contained in cigarette smoke are directly harmful to the development of the baby.

Also, smoking exposes the fetus to various complications:

– low birth weight: tobacco is the leading preventable cause of intrauterine growth retardation (IUGR). The greater the number of cigarettes smoked daily, the greater the delay. For every 10 cigarettes smoked per day, it is estimated that the baby’s weight will decrease by 200 g compared to a future mother who does not smoke (6)

– an increased risk of fetal malformation

– premature childbirth

These effects are dose-dependent: the more the expectant mother smokes, the greater the risk to the fetus.

After birth, smoking during pregnancy is responsible for the baby:

• a risk of sudden death multiplied by 2 (7)
• increased respiratory problems (asthma, ear infections, pneumonia)

It is advisable to completely stop smoking before pregnancy in order, on the one hand, to optimize the chances of conception, and on the other hand to start a pregnancy free from any tobacco contamination potentially harmful to the fetus and the pregnancy. According to specialists, the ideal is to wait for a cycle of cell regeneration without tobacco; thus cells will not be exposed to toxic molecules in tobacco. However, it is never too late to quit smoking, even once you are pregnant.

In pregnant women, psychological and behavioral approaches are favored. Nicotine substitutes can be used in case of failure, but only under medical supervision. Health Insurance covers these nicotine substitutes up to 150 euros per year, on medical prescription from a doctor or midwife.

Title fifth paragraph

The case of passive smoking

Fifth paragraph

Passive smoking in utero also has consequences for the fetus and the course of pregnancy. The substances contained in cigarette smoke are inhaled by the mother-to-be, pass into her blood and therefore that of the fetus via the placenta, which does not filter all the chemicals. A study (8) thus demonstrated levels of nicotine in the amniotic fluid in pregnant women who did not smoke but were exposed to tobacco, as well as in the urine of the baby at birth.

A meta-analysis (9) showed that passive smoking in pregnant women was linked to lower birth weight, smaller head circumference and a greater risk of birth defects.