[Lifestyle recommendations for prevention of spontaneous preterm birth in asymptomatic pregnant women]

To establish recommendations for lifestyle of pregnant women and its impact on spontaneous preterm births.

We searched Pubmed and Cochrane databases and checked reference lists of retrieved studies. This review of the literature concerns only women who have no symptoms for the ongoing pregnancy.

Concerning maternal occupation during pregnancy, there is a mild increase of the risk of preterm birth only for women who work more than 40hours a week or who have hard working conditions according to a fatigue score (LE2). With a weekly working time of 35hours, it is not recommended to prescribe routinely a sick leave to pregnant women in order to prevent preterm birth (grade B). Practicing exercise during pregnancy does not increase the risk of preterm birth before 37 weeks (LE2) and is recommended for women with normal pregnancy (grade A). Sexual intercourses during pregnancy do not increase the risk of prematurity (LE2), even for women with a history of preterm birth (LE3). A dietary pattern including vegetables, fruits and whole grain cereals during pregnancy might be associated with a lower risk of spontaneous preterm birth (LE3), while vitamin D and omega-3 supplementation has no effect on the gestational age of delivery (LE1). A dietary pattern including fruits, vegetables and whole grain cereals is thus recommended (grade C). Smoking is associated with spontaneous preterm birth (NP2). Smoking cessation interventions can result in 6 % smoking withdrawal in late pregnancy and 14 % reduction of preterm birth, while nicotine replacement therapies taken alone, such as nicotine-based patches, has no effect on both outcomes. Smoking cessation is also recommended in pregnant women, whatever the gestational age (grade A). Psychological disorders such as depression, anxiety and maternal stress are significantly associated with preterm birth (LE1). Among asymptomatic patients with a short cervix, bed rest is not associated with a reduction of preterm birth (LE3), and is also not systematically recommended (grade C). For multiple pregnancies without any symptoms, systematic hospitalization with bed rest is not recommended (grade A), especially since bed rest is associated with more thromboembolic events (LE3).

Among preventable risk factors of spontaneous prematurity, cessation of smoking has been demonstrated to be effective on the decrease of preterm birth. A dietary pattern including vegetables, fruits and whole grain cereals might be also associated with a reduction of spontaneous prematurity.