怀孕7周抽血即可知胎儿性别-英语点津

美国塔夫茨大学医学院的一个专家小组经过实验证明，孕妇在怀孕7周时就可以采集血样进行胎儿性别检测，而不必等到怀孕3个月后接受超声波检查。目前这项检测可以在欧洲多个医院进行，花费约255英镑。这一研究成果对患有伴性遗传病的父母具有极大意义。但是也有人质疑说如果胎儿性别鉴定变得更加容易，可能会有父母因为对腹中胎儿的性别不满意而选择流产。

'Is it a boy or a girl?' is one of the first questions parents-to-be want to know the answer to.

Now, thanks to a simple blood test they can find out with surprising accuracy at about seven weeks.

Though not widely offered by doctors, gender-detecting blood tests have been sold online to consumers for the past few years.

怀孕7周抽血即可知胎儿性别

Now researchers have found they really do provide early and accurate results. The test looks for small pieces of the male sex chromosome in the mother's blood and reveals if a mother is carrying a baby boy as early as seven weeks into the pregnancy. The team, from the Tufts University School of Medicine, said the test may be particularly valuable for families that harbour sex-linked genetic disorders like haemophilia.

Because such disorders mostly strike boys, knowing that the baby is a girl could spare the mother diagnostic procedures, such as amniocentesis, that carry a small risk of miscarriage.

'It could reduce the number of invasive procedures that are being performed for specific genetic conditions,' said study author Dr Diana Bianchi.

The method called cell-free foetal DNA is available in many European hospitals and costs around £255. It is not currently not available from doctors in the United States but is available online.

'What they are finding in England is that many women are not going on to have the invasive tests,' Dr Bianchi said.

In those procedures, doctors either extract some of the fluid that surrounds the foetus but this can cause a small number of mothers to miscarry.

However, some researchers warned the test could be misused to terminate a pregnancy if the baby isn't of the desired sex.

'What you have to consider is the ethics of this,' said Dr Mary Rosser at the Montefiore Medical Center in New York.

'If parents are using it to determine gender and then terminate the pregnancy based on that, that could be a problem. 'Remember, gender is not a disease.'

In a fresh look at the medical evidence for the blood test, Bianchi and her colleagues analyzed 57 earlier studies that included more than 6,500 pregnancies.

They found parents could trust the test 98.8 percent of the time when it said they would have a boy, and 94.8 percent of the time when it indicated a girl.

The current non-invasive alternative - an ultrasound done at the end of the first trimester (12 weeks) - isn't always good at spotting a baby's sex. Dr Bianchi said she owns stock in privately held Verinata Health, a company that is developing cell-free foetal DNA tests for Down syndrome, although that company had no role in the new study. The study was reported in the Journal of the American Medical Association.