[Preliminary study on the relationship between biological rhythm changes and pregnancy complications during pregnancy].

To study the characteristics of heart rate rhythm in pregnant women at different trimester of pregnancy, and to explore the relationship between the basic rhythm of heart rate and pregnancy complications. Thirteen pregnant women who were diagnosed with normal early pregnancy in the Reproductive Center of the Second Affiliated Hospital of Soochow University from June 2018 to December 2019 were prospectively selected. Personal files were created and the heart rate data of pregnancy women was collected 24 hours a day by wearable devices until delivery. Prenatal examination and pregnancy outcomes were surveyed at follow-up. The cosine analysis method and the designed statistical module were used to analyze the long-term rhythm of pregnant women's heart rate. The heart rate of pregnant women showed a significant rhythm at different gestational weeks. Compared with the gestational week of 12, the midline-estimating statistic of rhythm(MESOR) increased significantly at the gestational week of 28 and 32 (t=-2.751,P=0.013;t=-2.314,P=0.032).The phase of rhythm shifted from 14∶00 pm in the first trimester of pregnancy (12 weeks) to 16∶00 pm in the second trimester (24 weeks) (t=2.613,P=0.018) and returned to 14∶00 pm at the third trimester (32 weeks) (t=-2.176,P=0.046). Season had no significant effect on the changes of MESOR, amplitude and phase of maternal heart rate in the first trimester (t=-0.356,P=0.729;t=-0.777,P=0.464;t=-0.434,P=0.673), while season had no significant effect on the changes of MESOR, amplitude and phase in the third trimester (t=-0.663,P=0.532;t=-0.209,P=0.841;t=0.625,P=0.592). The heart rate of one pregnant woman with natural delivery had rhythm disorder from the start of labor to delivery. The heart rate of one pregnant woman with premature rupture of membranes showed rhythm disorder before and after the rupture of membranes, and smaller amplitude. Rhythm disturbance may play a suggestive role in preterm delivery and labor initiation. In conclusion, pregnancy may cause changes in the internal heart rate rhythm. Maternal internal rhythm disturbance may occur when delivery or premature rupture of membranes occurs. The heart rate rhythm of pregnant women may be related to some common complications of pregnancy such as premature rupture of membranes.