Effects on the foetus of exercise in pregnancy.

Maternal training during pregnancy has been the subject for numerous investigations lately, which are presented in this survey. No studies in human beings have shown any negative effect of training on the embryogenesis. During physical training a small rise in foetal heart rate of 5-25 bpm is a common finding. This could be due to a reduction in oxygen delivery or more likely stimulation from maternal vasoactive hormones or training-induced uterine contractions. Foetal growth seems to be influenced by maternal activity, as some investigations have found significantly bigger babies born by moderately trained females compared to non-trained or heavily trained women. In the latter group the reduction could be explained by a reduced neonatal fat mass. Increased maternal temperature during training has not been found to lead to any foetal abnormalities. The results indicate that moderate training during pregnancy can be recommended with observance of simple directives.