Women should keep out of the hot sun in early pregnancy to protect their unborn babies, experts have warned.
Extra sensitivity to high temperatures can also make expectant mothers feel unwell, they said.
The warning, from the Royal College of Obstetricians and Gynaecologists (RCOG), comes as temperatures begin to rise across the UK.
Some studies have suggested that babies can be affected by heat during the first 12 weeks of pregnancy.
One study, published in the journal BJOG in 2005, found that exposure to high temperatures in the first three months could lead to slightly lower birth weight.
Similarly, exposure to low temperatures in the final three months of pregnancy had a similar effect.
The researchers, from the University of Bristol, concluded that an ‘increasing occurrence of temperature extremes, in particular, heat waves’could have important public health implications.
The RCOG made its comments today in anticipation of a heatwave this summer.
It said babies develop most rapidly in the first three months of pregnancy and pregnant women are also more sensitive to high temperatures, which can make them feel unwell.
The College stressed that women should not panic, but take steps to protect themselves.
RCOG spokeswoman, Maggie Blott, said: ‘Women in their first stages of pregnancy in the summer should be aware of the health risk surrounding increases in temperature.
‘Pregnant women should stay out of the sun, wear loose clothing, keep well hydrated and eat healthy food little and often.’
The RCOG also issued a list of tips to help keep all expectant mothers and their babies safe. It said:
- when going out, wear hats and light, loose clothes made of natural fibres such as cotton
- apply sunscreen if you are out for some period of time
- drink plenty of fluids and keep cool by spraying your face and neck with cold water
- follow the nutritional advice provided by your midwife and/or obstetrician, but eat more light meals such as salads, vegetables and fruits. Avoid coffee, tea and alcohol
- limit going out at the hottest point of the day, between 11am and 3pm
- avoid strenuous exercise. The RCOG advises women that light to moderate exercise during pregnancy is fine. But, during a heatwave, it is important to ensure that your body temperature is stable.
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