妊娠检测过快时会漏诊妊娠
NEW YORK, Oct 09 (Reuters Health) - Women should hold off on taking a home pregnancy test for a week to 10 days after the first day of a missed period, researchers suggest. They found that earlier testing may miss about 10% of pregnancies.
Their study did not evaluate home test kits specifically, but detected pregnancies using the same hormone marker home tests look for. In fact, since the method they used is much more sensitive than home kits, the researchers conclude that early use of home products is likely to miss even more pregnancies.
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That is not to say that home pregnancy tests are generally unreliable, the study's author said in an interview.
"Home kits are pretty good," Dr. Allen J. Wilcox, of the National Institute of Environmental Health Sciences in Durham, North Carolina, told Reuters Health.
The problem, he said, is that many products claim they can be used on the first day of a missed period--which, according to the study finding, is too early to get a definitive answer.
, 百拇医药
In a study of more than 200 women aged 21 to 42, the investigators found that 10% of pregnancies would have been missed if the women had relied on a test taken on the first day of a missed menstrual period. This is because the embryo had not yet implanted in the womb in these cases.
The time it takes for an early embryo to implant varies from woman to woman, Wilcox explained. So while many women may get an accurate pregnancy-test result as soon as they miss a period, others will not. The danger in a false-negative test, he and his colleagues point out, is that women may not avoid some of the exposures--such as medications or workplace chemicals--that they would have if they believed they could be pregnant.
, 百拇医药
"This unfounded assurance could have important consequences," they write in the October 10th issue of The Journal of the American Medical Association.
Wilcox suggested that women wait 7 to 10 days after the first day of a missed period to take a home pregnancy test. If the result is negative, but menstruation does not resume, the pregnancy test should be taken again. Alternatively, a doctor can take a blood test that is more accurate than the urine-based home tests.
But while pregnancy is the most common reason for missed periods, there are other causes. Birth control pills, excessive exercise and low body weight can all disrupt the menstrual cycle. Other factors include breast-feeding, certain medications and the beginnings of menopause., 百拇医药
Their study did not evaluate home test kits specifically, but detected pregnancies using the same hormone marker home tests look for. In fact, since the method they used is much more sensitive than home kits, the researchers conclude that early use of home products is likely to miss even more pregnancies.
, http://www.100md.com
That is not to say that home pregnancy tests are generally unreliable, the study's author said in an interview.
"Home kits are pretty good," Dr. Allen J. Wilcox, of the National Institute of Environmental Health Sciences in Durham, North Carolina, told Reuters Health.
The problem, he said, is that many products claim they can be used on the first day of a missed period--which, according to the study finding, is too early to get a definitive answer.
, 百拇医药
In a study of more than 200 women aged 21 to 42, the investigators found that 10% of pregnancies would have been missed if the women had relied on a test taken on the first day of a missed menstrual period. This is because the embryo had not yet implanted in the womb in these cases.
The time it takes for an early embryo to implant varies from woman to woman, Wilcox explained. So while many women may get an accurate pregnancy-test result as soon as they miss a period, others will not. The danger in a false-negative test, he and his colleagues point out, is that women may not avoid some of the exposures--such as medications or workplace chemicals--that they would have if they believed they could be pregnant.
, 百拇医药
"This unfounded assurance could have important consequences," they write in the October 10th issue of The Journal of the American Medical Association.
Wilcox suggested that women wait 7 to 10 days after the first day of a missed period to take a home pregnancy test. If the result is negative, but menstruation does not resume, the pregnancy test should be taken again. Alternatively, a doctor can take a blood test that is more accurate than the urine-based home tests.
But while pregnancy is the most common reason for missed periods, there are other causes. Birth control pills, excessive exercise and low body weight can all disrupt the menstrual cycle. Other factors include breast-feeding, certain medications and the beginnings of menopause., 百拇医药