Passive smoking increases sleep disturbance among pregnant women

Pregnant women exposed to passive smoking are more likely to have sleep disturbances such as subjective insufficient sleep, difficulty in initiating sleep, short sleep duration, and snoring loudly or breathing uncomfortably, according to a study published in the September 1 issue of the journal SLEEP.

The study, authored by Takashi Ohida, MD, of Nihon University in Tokyo, Japan, focused on the responses of 16,396 and 19,386 pregnant women in Japan to two cross-sectional questionnaire surveys in 2002 and 2006, respectively.

The results also showed that pregnant women who smoke had the same sleep disturbances, and also experienced excessive daytime sleepiness and early morning awakening.

Dr. Ohida noted that in the surveys, the spouse was the source of the environmental tobacco smoke for 80 percent or more of pregnant women. The prevalence of smoking among Japanese men was 53 percent, which is higher than that among men in the United States (26 percent) or in the United Kingdom (27 percent). With this in mind, it is important to study the issue of passive smoking among Japanese women and their health, added Dr. Ohida.

“The relationship between passive smoking exposure and some negative health outcomes in pregnant women could be mediated by the ability of passive smoke to disrupt sleep,” said Dr. Ohida. “Educational programs that point out the adverse effects of passive smoking during pregnancy could help improve sleep hygiene in this group of individuals and help prevent other negative health outcomes associated with disturbed sleep.”

A woman’s body goes through drastic changes during and after pregnancy. These changes can be physical, hormonal and emotional. In addition to smoking or being exposed to second-hand smoke, all of these changes can also affect a woman’s sleep.

Most pregnant women experience daytime fatigue even though they may get more sleep. This is because the quality of their sleep tends to be worse. Physical discomfort and awakenings are common. The third trimester tends to be the time when it is hardest to sleep well.

Studies show that snoring often increases during pregnancy. Obstructive sleep apnea (OSA) also may develop as the pregnancy progresses. Warning signs for OSA may become more evident. These include gasping, choking sounds and pauses in breathing. OSA is more likely to develop if a woman had a high body mass index prior to the pregnancy.

Two other sleep disorders that are more common during pregnancy are restless legs syndrome (RLS) and sleep related leg cramps. RLS affects nearly 25 percent of pregnant women. RLS may be related to low iron. So women who must take iron supplements during pregnancy may have a lower risk of RLS. Leg cramps occur in about 40 percent of pregnant women. They tend to go away after delivery.

Experts recommend that pregnant women, and other adults, get 7-8 hours of sleep each night for good health and optimum performance.