Studies on Training During Pregnancy

Following up on the last post here are a couple of studies courtesy of Cassandra Forsythe (the woman busting booty in the previous videos).

First up

Long-term outcome after exercising throughout pregnancy: fitness and cardiovascular risk
James F. Clapp, III, MD
Am J Obstet Gynecol. 2008 November; 199(5): 489.e1–489.e6.

OBJECTIVE
The objective of the study was to test the null hypothesis that continuing vigorous weight-bearing exercise throughout pregnancy has no discernible long-term effect on indices of fitness and/or cardiovascular risk.
STUDY DESIGN
This was a follow-up observational study of the fitness and cardiovascular risk profile of 39 women conducted on the General Clinical Research Center at the University of Vermont. Data were analyzed using the paired Student t test, analysis of variance, and linear regression.
RESULTS
Women who voluntarily maintain their exercise regimen during pregnancy continue to exercise over time at a higher level than those who stop. Over time they also gain less weight (3.4 vs 9.9 kg), deposit less fat (2.2 vs 6.7 kg), have increased fitness, and have a lower cardiovascular risk profile than those who stop.
CONCLUSION
Women who continue weight-bearing exercise during pregnancy maintain their long-term fitness and have a low cardiovascular risk profile in the perimenopausal period.

BJOG. 2006 Nov;113(11):1239-47. Epub 2006 Sep 15.

Uterine blood flow during supine rest and exercise after 28 weeks of gestation.
Jeffreys RM, Stepanchak W, Lopez B, Hardis J, Clapp JF 3rd.

Department of Obstetrics and Gynecology and the Schwartz Center for Metabolism and Nutrition, MetroHealth Medical Center, Cleveland, OH 44109, USA.

OBJECTIVE: To test the null hypothesis that, after 28 weeks of gestation, uterine blood flow during supine rest and supine exercise is no different than uterine blood flow at left-lateral rest. DESIGN: In vivo experimental study in pregnant women. SETTING: Department of Obstetrics, MetroHealth Medical Center, Cleveland, OH, USA. POPULATION: Fourteen, physically active, late-pregnant women who continued supine exercise throughout gestation. METHODS: Studies were carried out between 29 and 38 weeks of gestation. Maternal blood pressure, maternal heart rate, and ultrasound estimates of volume blood flow in the right ascending branch of the uterine artery were obtained serially at rest in the left-lateral position, at rest in the supine position, during and immediately after 10 minutes of supine exercise, and again at rest in the left-lateral position. Exercise sessions included alternating 60- to 90-second periods of abdominal crunches and leg exercise at moderate/high intensity (Borg's rating of perceived exertion 14 +/- 1). MAIN OUTCOME MEASURES: Blood pressure, heart rate, and uterine artery volume flow. RESULTS: Data are presented as the mean +/- SD. Maternal heart rate and blood pressure were unchanged at supine rest but increased during supine exercise (heart rate increased from 76 +/- 9 to 98 +/- 12 beats per minute, mean arterial pressure increased from 81 +/- 6 to 102 +/- 12 mmHg). Volume flow fell from 410 +/- 93 to 267 +/- 73 cc/minute after 5 minutes of supine rest and then, during supine exercise, increased to 355 +/- 125 cc/minute. Uterine artery luminal diameter and blood flow correlated directly with tissue weights at birth (r(2) values between 0.32 and 0.59). CONCLUSIONS: In physically active women, uterine blood flow decreases during both supine rest and supine exercise but the decrease in the former is twice that seen in the latter.

Needless to say any woman should listen to her doctor before starting to exercise, and one should undertake exercise with the help of a qualified professional - make sure your trainer has taken courses in pre and post-natal training.