Fetal umbilical artery Doppler response to graded maternal aerobic exercise and subsequent maternal mean arterial blood pressure: predictive value for pregnancy-induced hypertension

Assessment of physical fitness during pregnancy: validity and reliability of fitness tests, and relationship with maternal and neonatal health - a systematic review

Objectives

To systematically review studies evaluating one or more components of physical fitness (PF) in pregnant women, to answer two research questions: (1) What tests have been employed to assess PF in pregnant women? and (2) What is the validity and reliability of these tests and their relationship with maternal and neonatal health?

Design

A systematic review.

Data sources

PubMed and Web of Science.

Eligibility criteria

Original English or Spanish full-text articles in a group of healthy pregnant women which at least one component of PF was assessed (field based or laboratory tests).

Results

A total of 149 articles containing a sum of 191 fitness tests were included. Among the 191 fitness tests, 99 (ie, 52%) assessed cardiorespiratory fitness through 75 different protocols, 28 (15%) assessed muscular fitness through 16 different protocols, 14 (7%) assessed flexibility through 13 different protocols, 45 (24%) assessed balance through 40 different protocols, 2 assessed speed with the same protocol and 3 were multidimensional tests using one protocol. A total of 19 articles with 23 tests (13%) assessed either validity (n=4), reliability (n=6) or the relationship of PF with maternal and neonatal health (n=16).

Conclusion

Physical fitness has been assessed through a wide variety of protocols, mostly lacking validity and reliability data, and no consensus exists on the most suitable fitness tests to be performed during pregnancy.

PROSPERO registration number

CRD42018117554.

Doppler examinations of fetal and uteroplacental blood flow in AGA and IUGR fetuses before and after maternal physical exercise with the bicycle ergometer

OBJECTIVE

To study changes in uteroplacental and fetal circulation after maternal exercise in appropriate-for-gestational-age fetuses (AGA) and intrauterine-growth-retarded fetuses (IUGR).

MATERIALS AND METHOD

33 women with an uncomplicated course of pregnancy and ten women with IUGR were examined. Physical stress was caused through a bicycle ergometer with 1.25 W/kg maternal weight. Doppler examinations were performed in the umbilical artery, fetal aorta, middle cerebral and in the uterine artery. Fetal heart rate was documented by monitoring. Maternal lactate and glucose levels as well as maternal blood pressure and heart rate were recorded.

RESULTS

No significant changes after cycling could be observed in umbilical and uterine vessels either in the normal pregnancies or in pregnancies with IUGR. In contrast, in the fetal aorta an increase of the RI was recorded in both groups (an increase of 16% [P<0.01] and 18% [P<0.05], respectively for AGA and IUGR cases). In cerebral arteries a decrease of the RI was observed after cycling in both groups (a decrease of 24% [P<0.01] and 13% [P<0.05], respectively for AGA and IUGR cases). In AGA fetuses the RI of the aorta and middle cerebral artery returned to pre-test level by the 18th minute of examination. In IUGR fetuses the RI of the aorta and middle cerebral artery did not return to pre-test levels at the end of the test. Fetal heart rate remained unchanged in both groups. Maternal blood pressure and heart rate increased during the exertion phase but returned to initial values at the end of the test. A 21% and 24% (for AGA and IUGR groups respectively) reduction of maternal glucose values after exercise was observed (P<0.001). Lactate values doubled in both groups after exercise (P<0.001).

CONCLUSION

From the results obtained we conclude that maternal exercise does not significantly alter uterine and umbilical perfusion in AGA and IUGR pregnancies, suggesting an absence of change in the uterine vascular bed resistance. However, submaximal maternal exercise was followed by fetal cerebral vasodilatation and an increase of resistance in the fetal aorta that was more evident in IUGR fetuses. This might be due to slight fetal hemoglobin desaturation in those cases.

The elite athlete and exercise in pregnancy

As the opportunities for women to compete in elite sports competition increase, it is inevitable that pregnancy will occur during training and competition. The effect of the high-intensity exercise needed to compete at the elite level will be found in anatomic changes such as ligament relaxation, change in posture, and increased weight. These will all detract from the ability to attain peak performance. The effect of the high-intensity training on the athlete and the fetus must also be considered. The physiological and metabolic changes will have a variable effect; however, awarenees of these changes should prevent problems. There is some evidence suggesting an increase in low birthweight infants but no evidence of preterm birth. Unfortunately, much of our information is based on limited studies, so caution and careful evaluation are essential.

Exercise guidelines for pregnant women

Despite remarkable improvements in high technologies and an increase in the number of studies related to exercise for pregnant women, the guidelines for maternal exercise remain contradictory. The effects of exercise in pregnant women and cardiovascular modifications due to pregnancy, and effects of maternal exercise on the fetal environment, including uterine and umbilical hemodynamic changes, are reviewed. Suggested future directions in this area of nursing science are discussed.