There are some methods of prediction, but it is not advocated that all groups of people make such predictions. First of all, high-risk groups, with high-risk factors for preterm birth, are prone to preterm birth and can be predicted.
There are now three main categories of means of forecasting. First, according to the high risk factors of preterm birth, such as having a history of preterm birth before, of course, this time it is necessary to pay considerable attention to her, and it may be necessary to predict her, because it has occurred prematurely, and this time it is easy to recur preterm birth, which is itself an indicator.
The second category, now more respected is the use of B ultrasound, look at the shape and length of the cervix throughout pregnancy, which is currently recommended internationally. Because as the gestational age gradually increases, the cervix gradually becomes shorter, and this is the signal that preterm birth may occur. Or at a certain gestational age, the value is lower and smaller than this week, and it is also considered that premature birth will occur.
For example, in the past, there were high risk factors, which is such a group of people, and now it is recommended to be about 22 weeks pregnant, and it can also be earlier, such as 16 or 18 weeks, routinely do B ultrasound, look at the length and shape of the cervix, the length of the cervix should be at least greater than 3 cm, if it is less than 2.5 cm, the risk of premature birth will be very large, so this is very important. If it was not particularly short at that time, but with the increase of gestational age, such as 28 weeks of pregnancy, 32 weeks of pregnancy, gradually shortened again, less than 2 centimeters, and the inner mouth was expanded, because the cervix has a length, the outer mouth may not be expanded, but the inner mouth is expanded, the so-called V-shape, so-called may also be a transition. Of course, if through some treatment, the position changes, such as putting the ass a little higher, do not compress the cervix, sometimes it will change again, the inner mouth may be retracted again, so this is also a predictive method, which is through the B ultrasound to see the cervical length form.
Another prediction is fFN, that is, vaginal secretions, look at fetal fibronectin, fFN is actually called fetal fibronectin. In the early stages, such as before 20 weeks of pregnancy, vaginal secretions may have, after 35 weeks of pregnancy there will be vaginal secretions, so take it to predict, that is, between 22 weeks and 35 weeks of pregnancy, look at the vaginal secretions, should not appear sometimes, the predictive value of this value, mainly its negative predictive value, that is, between 22 and 35 weeks of pregnancy to measure fFN, if it is negative, it can be proved that the probability of no premature birth is relatively large. If you combine the length and shape of the cervix, if the length of the cervix is also long, greater than 3 cm, at least greater than 2.5 cm, fFN is negative again, the two indicators are combined, it can be said that within two weeks, the probability of premature birth is almost non-existent, very low. If fFN is positive, the predicted probability of preterm birth is not particularly high, combined with other conditions, because sometimes, there may be some false positive conditions. So this indicator, mainly to see the negative prediction value.