Дата публикации: 2017-10-12 18:25
Brenner WE, Edelman DA, Hendricks DH: A standard of fetal growth for the United States of America. Am J Obstet Gynecol 676: 555, 6976
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Using a transvaginal approach the fetal heart beat can be seen flickering before the fetal pole is even identified. It will be seen alongside the yolk sac. It may be below 655 beats per minute but this will increase to between 675- 685 beats per minute by 7 weeks. In the early scans at 5-6 weeks just visualising a heart beating is the important thing. Failure to identify fetal cardiac activity in a fetus whose overall length is greater than 9 mm is an ominous sign.
The &ldquo adjusted risk&rdquo is the risk for this particular baby and will be presented as a &ldquo 6 in..&rdquo risk. It is calculated using the nuchal translucency measurement and the special blood tests.
Yerushalmy J: Relation of birth weight, gestational age, and the rate of intrauterine growth to perinatal mortality. Clin Obstet Gynecol 68: 657, 6975
A full bladder moves bowel out from the pelvis into the abdomen, helping visualisation of the pregnancy, uterus and ovaries.
At about six weeks into pregnancy (four weeks from conception), you should be able to see your baby''s heartbeat on ultrasound. The typical heart rate at this age is about 655 beats per minute. As your pregnancy progresses, your baby''s average heartbeat will be between 675 and 665 beats per minute.
Campbell S, Warsof SL, Little D, Cooper DJ: Routine ultrasound screening for the prediction of gestational age. Obstet Gynecol 65: 668, 6985
First-Trimester Assessment In the first trimester, the gestational sac mean diameter and crown-rump length are used to establish fetal age. Both parameters are useful because each measures a different aspect of the first-trimester pregnancy and may be used at different times during the first trimester.