Exercise during pregnancy¹ can be good for the developing baby as well as for the mother, research suggests.

有研究称，孕妇在怀孕期间做运动有助于胎儿的发育，并且对孕妇也有利。

Aerobic² exercise during pregnancy 'can benefit baby'

A team from the Kansas City University of Medicine and Biosciences（生物科学） suggest it is linked to better foetal（胎儿的） heart health and nervous system development.

The findings from their pilot study（初步研究） of 26 women are being presented to the American Physiological³ Society's conference in New York.

A UK expert said pregnant women should discuss exercise levels with their GP.

The researchers wanted to see if maternal⁴（母亲的，母系的） exercise had cardiovascular（心脑血管的） benefits for the foetus.

They also wanted to see if foetuses whose mothers exercised had increased breathing movements compared to non-exercise exposed foetuses.

Foetal breathing is a "practice" movement where a baby developing in the womb（子宫） gets ready to breathe after it is born.

It is also a sign of how well the respiratory（呼吸的） system and central nervous system are developing.

Moderate（适度的，稳健的） exercise

The scientists used a non-invasive（侵入的，攻击性的） device to measure the magnetic（有磁性的，有吸引力的） fields produced by the electrical activity of maternal and foetal heart rates.

It was also able to pick up foetal movements including breathing, body movements, hiccups⁵（打嗝） and sucking.

The women studied were aged⁶ between 20 and 35 and were checked between the 36th and 38th weeks of pregnancy.

They were classed as exercisers if they did moderate intensity⁷ aerobic（有氧的） exercise such as moderate to vigorous（精力充沛的） walking, stationary⁸（不动的） bicycling and running for at least 30 minutes, three times per week. Most were doing more.

The researchers then compared them with pregnant women who did not exercise regularly.

Dr Linda May, who led the study, said: "Foetal breathing movement and the nervous system were more mature in babies exposed to exercise."

She said further research was needed, both to look at more pregnancies⁹ and to evaluate the health of babies once they had been born.

But she said understanding more about how to improve the development babies' nervous system could aid understanding of cot death（婴儿猝死综合症）.

"Some researchers think it has to do with something being wrong in the central nervous system, which affects respiration¹⁰（呼吸）.

"Babies aren't able to wake up and breath for themselves if they need to."

She said this study had shown the babies of women who exercised had a more mature respiratory system, suggesting they would fare better after birth.

'Do not overheat'

Dr May said it was safe for women to exercise while pregnant.

But she said the team did not yet have evidence about what the minimum beneficial level of exercise in pregnancy was.

Patrick O'Brien, a consultant¹¹ obstetrician and spokesperson for the Royal College of Obstetricians and Gynaecologists said the study was interesting and worth following up, although it was small.

He added: "This is an interesting finding and one which should encourage women to keep healthy when pregnant.

"Pregnant women should consult their midwives（助产士） and doctors on the types of exercise they could do when pregnant and how much."

Mr O'Brien said excessive exercise during pregnancy could be dangerous for the unborn baby if a woman becomes too hot or lets their heart rate go over 130 beats per minute.

But he said there was is no increased risk of miscarriage¹²（错误） or premature¹³（早熟的，过早的） labour linked to exercise.

He advised: "Keep within your comfort zone so that you can still hold a conversation."