A comparative study of autonomic function tests (sympathetic and parasympathetic) in three trimesters of pregnancy

Background: Women exhibit large variations in behavior and hormones during different phases of their reproductive life. Emotions, hormones are much under command of autonomic nervous system. During pregnancy a woman’s body focuses its primary attention to nurture the new one and the body automatically prioritizes the needs of her unborn. The autonomic nervous system is known to play a major role in cardiovascular regulation in pregnancy, which is associated with lots of changes in hemodynamics, including blood pressure, cardiac output and also in systemic vascular resistance. Objective: The present study was done to evaluate the autonomic (sympathetic and parasympathetic) nervous system sequentially during the three trimesters of pregnancy. Materials and Methods: Total 90 healthy pregnant women having no major illness, were considered for the study and grouped as group I 30 subjects of first trimester, group II 30 subjects of second trimester and group III, 30subjects of third trimester. All subjects were evaluated by CANWIN –Cardiac Autonomic Neuropathy Analyser. Result: Women in group I show normal parasympathetic function plus mild parasympathetic (PNS) dysfunction; and moderate sympathetic (SNS) dysfunction .Women in group II shows mild PNS dysfunction with moderate SNS dysfunction. Women in group III shows moderate parasympathetic and sympathetic dysfunction. Conclusion: The autonomic dysfunction starts from the first trimester of pregnancy. The present study thus can be an effective tool to anticipate the pregnancy related cardiovascular complications such as pregnancy induced hypertension, pre-eclampsia thereby decreasing the morbidity, and improving the outcome of pregnancy of healthy mother and healthy baby.