Restless Legs Syndrome more common in Pregnancy

Restless legs syndrome (RLS) is a condition in which a person feels an unpleasant sensation in the legs when at rest or during sleep.

RLS produces an irresistible urge to move the legs.

The sensations can persist often, interrupting sleep throughout the night.

RLS can adults, elders, anemia patients and pregnant women. In half of the cases, the family history of the symptoms is reported.

A family history of the symptoms is reported in up to half of cases. Symptoms often increase during menstruation or menopause, and as many as 25% of pregnant women are affected.

People with RLS feel pulling, crawling, or tingling sensations. They get temporary relief when they move their legs.

Restless legs syndrome occurs in 26% of pregnancies, peaking in the 7th and 8th months but sharply decreasing around the time of delivery, an Italian study of more than 600 women revealed.

Although an association between restless legs syndrome (RLS) and pregnancy was first reported in 1940, a study by Mauro Manconi, M.D., of Vita-Salute University in Milan and associates is the first large epidemiologic study to explore the connection.

The researchers concluded that pregnancy is an important risk factor for RLS. A total of 606 women were interviewed within 2 days about their medical and family histories, pregnancy histories, iron and folate therapy, sleep habits, and presence of sleep disorders.

Follow-up interviews were conducted at 1, 3, and 6 months after delivery with 161 women who met international diagnostic criteria for RLS, including:

• Motor restlessness
• Urge to move the limbs
• Worsening of symptoms in the evening or night
• Worsening of symptoms at rest, with at least partial and temporary relief by activity.

Of the 606 women in the study, 161 (26.6 percent) reported the occurrence of RLS, 101 of whom reported experiencing RLS for the first time. One-fourth of the women experienced RLS symptoms at least once a week, and 15 percent at least three times a week.

The appearance or worsening of RLS symptoms was generally around the sixth month, reaching a peak at the seventh and eighth months of pregnancy. RLS prevalence dramatically decreased around the time of delivery, ranging between five and six percent at six months after delivery.

Both groups had a similar mean daily in take and total duration of iron and folate supplementation during pregnancy.

However, a significant difference for hemoglobin and mean corpuscular volume values was found between the total RLS group and the healthy group.

Risk factors associated with RLS included maternal weight of greater than 79 kg and low hemoglobin levels. Only low hemoglobin was significantly associated with the development of RLS in pregnancy in women who never had the condition before.

Both legs were involved in 94% of cases, with only the knee to the ankle affected in 40%. About a fourth of women said their legs began to jerk before they fell asleep.

Sleep was significantly affected. Women with RLS reported sleep loss, longer sleep latency, more insomnia, and excessive daytime sleepiness than pregnant women without RLS.

The results on a significant difference in iron storage indicators support a hypothesis that a relative iron deficit could play a role in this form of RLS, though the rapid improvement of RLS symptoms after delivery gives more power to a hormonal rather than iron-related hypothesis.

Even if the real cause of the association between RLS and pregnancy remains unclear, this study is the first to show a significant correlation between low iron indicators values and the risk to develop RLS.

Further investigations are needed to evaluate the role of hormonal state and of personal genetic background predisposition in the cause of this temporary state of RLS.