To the one British couple in seven that has problems conceiving, twins sound like a dream come true. So when would-be parents tu

admin2017-03-15  42

问题     To the one British couple in seven that has problems conceiving, twins sound like a dream come true. So when would-be parents turn to in vitro fertilisation (IVF), they almost always opt to have as many embryos returned to the womb as they are legally allowed, even though they know that multiple births are especially risky. The result is that two-fifths of IVF babies are twins. And fertility treatment is now so common that it is distorting the nation’s demographics: around a quarter of all twins have been conceived in a petri dish.
    Sharing a womb is not an ideal start to life. Twins who survive their much higher rates of miscarriage are often born early and small, which puts them at higher risk of cerebral palsy, low IQ and even death during their first year. Their expectant mothers are more prone to high blood pressure, diabetes and heart problems. Around half of all twins are transferred to intensive-care units soon after birth.
    Now the Human Fertilisation and Embryology Authority (HFEA), which licenses fertility clinics in England and Wales, has decided enough is enough. On April 4th it started a three-month consultation on changes in the way fertility treatment is carried out. The new rules, due to come into force in October, aim to halve the number of twin IVF pregnancies.p for discussion are various possible ways to do this. They include educating fertility doctors and their patients about the dangers of multiple births; imposing a limit—probably 10%—on the proportion of births which twins may account for at a clinic; and enforcing rules that set out exactly when clinics are allowed to return two embryos to the womb. The idea is to ensure that only one embryo is put back in women most likely to conceive, whereas two are allowed to those less likely.
    Some countries, notably Nordic ones, have already managed to cut the number of twin births resulting from fertility treatment. Provided a woman is reasonably young and healthy, and has not already had many failed IVF attempts, in each IVF cycle only the embryo that develops best is returned to her womb. Any spares are frozen, to be thawed later if the first embryo does not survive. These carefully-selected women are almost as likely to get pregnant this way as if two fresh embryos had been put back in the first place, and the risk of multiple pregnancy is almost eliminated. Persuading patients and clinicians of the merits of this approach depends on generous state funding for fertility treatment: it seems that patients are willing to accept a slightly lower chance of conceiving in any one cycle in return for more attempts. Moral pressure is also brought to bear. In Finland fertility doctors are taken on tours of neonatal wards, so they get to see the tiny, suffering scraps of humanity bora too early because they were crowded in their mothers’ wombs.
    In Britain, though—unlike Finland and every other country that has successfully reduced IVF twin births— most infertile people must pay for their own treatment. Government guidelines, issued in 2004, say that all patients for whom IVF is "suitable" should have three treatment cycles paid for by the National Health Service (NHS), but rarely does this happen. Those patients who get public money are usually offered only one IVF cycle, and in some areas there is no public funding of IVF at all.
    This means that binding rules are likely to be needed to cut the number of IVF twins in Britain. Otherwise, with a single IVF cycle costing around £5,000, patients will be unwilling to accept even a tiny reduction in their chance of pregnancy, and so will ignore the risks in favour of returning as many embryos as they can. It took strong words from the HFEA in 2001 to start to bring down the numbers of triplets conceived by IVF, followed by the threat and then the reality of stricter rules. Now that women under 40 can have at most two embryos put back, the rate has halved since its peak in 1998.
    Some experts consulted by the HFEA held that new rules which might reduce the chance of conceiving should be introduced only if more fertility treatment were paid for by the NHS—something that the HFEA does not have power to arrange. Others said that the risk inherent in multiple births was too urgent to wait for the NHS to change its spending priorities.
    The irony is that delivering and caring for twins costs 16 times as much as for a singleton. The HFEA’s advisors calculate that the money now spent on looking after desperately-ill premature IVF babies would be enough to pay for three treatment cycles for everyone who needs them. In the meantime, patients must weigh the risks of multiple pregnancy against the prospect of remaining childless.
    Even those most familiar with the sufferings of the infertile seem unsympathetic towards them. Only pregnancy is a more common reason than infertility for a woman to visit her doctor; yet a recent poll found that almost all family doctors thought patients who needed fertility treatment should pay for it themselves (not so those with varicose veins, for example). It is perhaps symptomatic of the low value placed on children and family life in general; another poll, last year, found that most Britons thought work, money and fun were all more important than having children.
To lower birth rate of twins, which of the following ways is NOT possible?

选项 A、Showing prospective parents the hazardous danger of giving birth to twins.
B、Taking grim measures to ensure every woman is put in one embryo.
C、Educating them that putting more embryos into womb would not increase fertility rate.
D、Displaying other skinny babies to parents .

答案B

解析
转载请注明原文地址:https://kaotiyun.com/show/SySO777K
0

相关试题推荐
最新回复(0)