Курение и Репродуктивное Здоровье

Smoking harms reproductive health: menstrual function, oral contraceptive use, fertility, problems in pregnancy and giving birth to low-weight babies.

Smoking affects ovarian function and decreases the female hormone estrogen. If you are planning to become pregnant, cigarette smoking can impair your fertility by adversely affecting ovulatory and tubal function, egg production and implantation. Smoking may cause you to have irregular menstrual cycles. Women who smoke also have an earlier menopause, which may increase their risk of osteoporosis, heart disease and other conditions for which estrogen provides a protective effect.

Women who smoke may be putting themselves at risk for irregular menstrual cycles. This may help explain why women smokers are more likely to be infertile and may undergo earlier menopause. It was proved that women who smoked at least 20 cigarettes a day were 4 times more likely to have short menstrual cycles (less than 25 days). Women who smoked 10 or more cigarettes a day were more than twice more likely to have irregular menstrual cycles than women who did not smoke. It was also discovered that smoking women have higher frequency of anovulatory cycles (cycles without ovulation) (D.Christensen, 1999).

Compared with nonsmokers, both current and past smokers have reduced gonadotropin- stimulated ovarian function. A history of increasing tobacco exposure was associated with decreasing serum estradiol concentrations, numbers of retrieved oocytes, and numbers of embryos (Van Voorhiset al, 1996).

The Combined Effects of Smoking and Contraceptive Pills

Smoking cigarettes while taking birth control pills dramatically increases risks of heart attack for women over 35. Smoking is far more dangerous to a woman's health than taking birth control pills, but the combination of oral contraceptive pill use and smoking has a greater effect on heart attack risk than the simple addition of the two factors.

Smoking cigarettes while taking birth control pills increases a woman's risk of having an ischemic stroke (three times more likely in pill users than in nonusers) or a hemorrhagic stroke (three to four times that of nonusers), according to a large World Health Organization (WHO) study.

Smoking – Pregnancy – Children

Between 12 and 22 percent of pregnant women continue to smoke throughout their pregnancies. Despite having increased knowledge of the adverse effects of smoking during pregnancy, it is estimated that only 18 to 25 percent quit smoking once they become pregnant. If you smoke while you are pregnant, you are putting yourself and your unborn child at increased risk for complications. Well-known risks of smoking during pregnancy are complications from bleeding and low-birth weight babies. Many studies document that smoking during pregnancy increases the risk of Sudden Infant Death Syndrome,  premature birth, stillbirth, placenta previa (the placenta grows too close to the opening of the uterus, a
condition that often leads to Cesarean delivery), placental abruption (the placenta prematurely separates from the uterus wall), premature rupture of uterine membranes and preeclampsia (a condition that results in high blood pressure and excess protein in the urine).
Smoking during pregnancy also reduces the newborn's lung function. If you are a smoker and a nursing mother, it is important to know that nicotine is found in breast milk, and therefore enters your baby's system.

If you have children, your smoke puts them at risk, too. Secondhand smoke has been shown to make children more susceptible to infections, including colds and flu, ear infections, and lower respiratory infections such as bronchitis and pneumonia. It also causes new cases of  asthma, as well as making existing cases of asthma worse.

(From NWHRC - The National Women's Health Resource Center)

Ovarian Hormones and Nicotine

Despite steady progress in the fight against nicotine addiction over the past 25 years, the percentage of female smokers is increasing. The United States may soon become the first society in history in which more women than men smoke. In part, this is because women are less likely to be able to quit, whether they try on their own or with the help of smoking cessation programs. This appears to be especially true for nicotine replacement therapies (such as nicotine patches or gum), which have helped a greater percentage of men than women in almost every study.

According to a new study by scientists at the University of Minnesota, differing levels of female sex hormones during the menstrual cycle are the reason for some women's inability to quit smoking.

The links between different parts of the menstrual cycle and mood are well established, and there is even some evidence that women smokers tend to smoke more at some points. The successful attempt to quit smoking may depend on where women are in their monthly cycle - those trying before ovulation can be more successful in quitting.

Experiment - Withdrawal effect

The researchers looked at a total of 200 women, who were asked to give up smoking either in the "follicular" stage of their cycle - the period leading up to ovulation, when an egg is produced by the ovary, or the "luteal" stage, the roughly two-week stage that completes the cycle.

Each stage is marked by differences in the hormones produced by the body.
After 30 days, 86% of the women who starting trying to give up during their follicular phase had "relapsed", and smoked at least one cigarette.
This compared to 66% of the group who had started in their luteal phase.
While the precise reasons for this remained unclear, the scientists from the University of Minnesota suggested that the hormone differences linked to the different menstrual phases could affect the severity of nicotine withdrawal symptoms felt by the quitters.
Hormones might even play a role in the speed at which nicotine is removed from the bloodstream by the body, they said.