Sleep disorders and changes in melatonin concentrations in pregnant women with preeclampsia

Abstract

Melatonin plays a significant role in the development of normal pregnancy, in particular, it contributes to the successful implantation of the fertilized egg, affects the act of childbirth, is actively produced by the trophoblast and placenta, reduces oxidative stress, in particular, with preeclampsia. In addition, melatonin is one of the essential hormones in the protection of the endothelium and stem cells from the oxidant stress. Objective – to study the mechanisms of development, terms of manifestation, and types of sleep disorders, as well as changes in the concentrations of melatonin in the blood of pregnant women with preeclampsia. Material and methods. 50 pregnant women at a mean age of 29.1±3.4 years who had preeclampsia in the 3rd pregnancy trimester were examined (experimental group). All women in the research group had a gestation term of 30-32 weeks of pregnancy. The control group consisted of 33 women with a mean age of 31.2±6.6 years who had an uncomplicated pregnancy. The presence of sleep disorders was established using a questionnaire: pregnant women were asked about the term of pregnancy in which complaints of sleep disorders appeared, the nature of sleep disorders, the frequency of episodes of sleep disorders (how many times a week such a condition was noted), etc. The concentration of melatonin in the venous blood of the examined pregnant women was also determined, for which IBL melatonin ELISA diagnostic kits manufactured by IBL, Germany were used. Blood was taken at 9:00 a.m., on an empty stomach, and all patients were analyzed at the same time of a day. Results and their discussion. The study showed that sleep disorders in pregnant women with pre-eclampsia, which complicates the pregnancy in the 3rd trimester, occurred earlier, compared to women with an uncomplicated course of pregnancy: pregnant women with pre-eclampsia were more likely to notice worsening of sleep, starting from 22-30 weeks of pregnancy (in 26.0 % of cases), while in pregnant women with a physiological course of gestation, similar complaints appeared mainly after 30 weeks. In the third trimester of pregnancy women with preeclampsia were more likely to wake up 2 or more times per night (in 68.0 % of cases) compared to controls (in 23.3 % of cases, p < 0.001) and 3 or more times per night per week (in 54.0 % of cases, in controls – in 16.7 % of cases, p < 0.001), which may be a consequence of a disorder of the function of the pineal gland. Women with preeclampsia were more likely (56.0 % vs. 13.3 % in the control group, p < 0.01) to use gadgets (electronic devices, mainly smartphones) for more than 2 hours after 9:00 p.m., which also negatively affects the function of the pineal gland. In pregnant women whose pregnancy was complicated by preeclampsia in the 3rd trimester, a significant (1.78-fold) decrease in the level of melatonin in venous blood taken at 9 a.m. was observed, compared to women with an uncomplicated pregnancy (p = 0.029). Conclusions. Sleep disorders in pregnant women with preeclampsia occur earlier and are more expressed compared to women with an uncomplicated course of pregnancy. The appearance of complaints of insomnia in the second trimester of pregnancy, in our opinion, can be considered a diagnostic sign of pineal gland dysfunction in preeclampsia. A decrease in the level of melatonin in pregnant women with preeclampsia, established against the background of minimal daily activity of the pineal gland (at 9 a.m.), indicates a decrease in the melatonin-producing function of the placenta which might have an impact on the condition of stem cells of fetus and placenta.