Exercise in Pregnancy for Reduction of Blood Pressure in Obese Patients

Hypertension affects 5-10 percent of pregnancies, and complications from hypertensive
disorders of pregnancy are the third leading cause of maternal death in the United States.
Hypertensive disorders of pregnancy, including preeclampsia, lead to preterm delivery,
morbidity and mortality of mother, fetus, and neonate, and are a predictor of development of
chronic maternal hypertension, cardiovascular disease, and renal disease. Maternal obesity
is increasing dramatically in the patient population, and is an independent risk factor for
hypertension and preeclampsia, increasing the risk by two- to four-fold. To date, no
effective preventative measure has been found to reduce the risk of preeclampsia or
hypertension in high risk pregnant patients. However, observational studies have shown that
patients who exercise or who have increased physical activity before and during pregnancy
have lower rates of preeclampsia, hypertension, and gestational diabetes. Exercise has been
shown in numerous studies to be safe in pregnancy, and is recommended by the American
College of Obstetrics and Gynecology as part of routine prenatal care. However, aerobic
exercise can be viewed by patients to be difficult to perform during pregnancy, particularly
when the patient is obese and at later gestations. Adherence to exercise regimens is
therefore low in this patient group. Dynamic resistance training has been shown to lower
mean blood pressure both acutely and long term in non-pregnant hypertensive patients, and
can be performed more easily by patients with mobility issues. This intervention has not
been studied in an obese pregnant population for its effects on blood pressure throughout
pregnancy.

The long term goal is to develop an intervention that will reduce the barriers to exercise
of obese pregnant women that will, in turn, reduce their risk of developing preeclampsia and
other hypertensive disorders of pregnancy. The specific objective of this proposal is to
study the effect of a structured resistance training exercise intervention on blood pressure
in obese pregnant woman, who would be considered high risk for development of hypertensive
disorders based on pre-pregnancy BMI. The central hypothesis is that obese pregnant
patients who participate in a regular, structured resistance training exercise regimen will
have a decrease in mean arterial blood pressure compared to obese pregnant patients who are
strongly encouraged to do aerobic exercise (lifestyle intervention) or who participate in
routine prenatal care. The investigators formulated this hypothesis, in part, based upon
previous studies found in the literature performed in non-pregnant hypertensive patients.
The investigators will extrapolate from the experience and methods of the collaborators, who
have studied the effects of exercise on gestational diabetes.

Inclusion Criteria:

- Patient's BMI must be ≥ 30 and ≤ 40.

- Established viable singleton pregnancy <13 weeks

Exclusion Criteria:

- Multiple gestations.

- Maternal diabetes established pre-pregnancy by standard guidelines

- Congenital or acquired heart disease

- Use of antihypertensive medication

- Inability to exercise

- Restrictive lung disease

- History of shortened/incompetent cervix

- History of preterm labor