The purpose of this study is to determine whether a noninvasive method of measuring certain aspects of blood circulation (e.g., blood pressure, cardiac output) is an accurate and reliable method to detect changes in pregnant patients. Specifically,the investigators are interested in patients diagnosed with high blood pressure during their pregnancy, as compared with normal pregnant patients. A noninvasive, accurate method of taking these measurements in pregnant patients is not currently available.

During pregnancy, many aspects of blood circulation, such as blood pressure, heart rate, cardiac output, and stroke volume, adapt to accommodate the increasing needs of a pregnant body. The circulatory system works harder to provide blood flow to the placenta and the growing fetus.

Currently, the devices that can give physicians detailed information on the status of the blood circulation of normal patients and those with high blood pressure during pregnancy are invasive to varying degrees. However, recently, a new noninvasive hemodynamic monitor (NonInvasive Cardiac Output Monitoring: NICOM) was introduced to the market. In studies with non-pregnant patients, the NICOM has been found to be accurate, precise and reliable. However, it has yet to be studied in the field of Obstetrics.

The purpose of this study is to find out if the NICOM is an effective tool for monitoring hemodynamic changes in pregnant women, both with normal and high blood pressure. We are planning to compare the hemodynamic profiles of normal pregnant patients, hypertensive pregnant patients, and non pregnant patients as a control group. If this monitor proves to be reliable in assessing these changes in the pregnant patients, this could have a great impact in optimizing the care of the patients with different medical conditions in pregnancy, such as increased blood pressure.

Inclusion Criteria:

• PIH diagnosed in 3rd trimester, not yet treated
• healthy pregnant patients in 3rd trimester
• healthy non-pregnant women

Exclusion Criteria:

• under age 18 or above age 40
• refusal to participate

Our study population includes healthy non-pregnant and pregnant patients in their 3rd trimester, as well as pregnant patients in their 3rd trimester with pregnancy-induced hypertension (PIH). Both normal groups will be recruited from the outpatient day-unit (healthy volunteers). Patients with PIH may be sent to labour and delivery for monitoring by their obstetricians.