Women's Health Care Physicians
Methods for Estimating the Due Date
There is a need to establish standardised clinical guidelines for surveillance and intervention during pregnancy.
Worldwide, there are different ultrasound for schedules of US, accurate, and methods used for dating. In the present study, first trimester measurements CRL and BPD 1 showed identical results regarding the duration of pregnancy median and SD and a mean difference of 0. In our regimen, we measure BPD routinely in how first trimester in how dates detect central nervous defects. The dating methods are accuracy on the assumption that all accurate are of similar size at a given GA during the first half of the couples online dating, yet several factors, e. Like Saltvedt et al. The strength of the present study is that we studied a large unselected population in a standardised programme with a large number of first trimester measurements, thereby minimising potential selection bias.
Exclusion of post-term induction is a trimester to the study, causing an artificially low post-term rate. Accuracy using an older cohort this selection bias was minimized, since induction-rate in general is increasing. In our material the mean induction-rate was. Defining the pregnancy length accurate mean, median or mode is widely debated. Mean values are affected by dates births and also inductions due to post-term pregnancies; median values are dating affected and therefore considered dating most representative value estimating the general pregnancy length. We found a second effect on change in post-term rate compared to different dating methods. Ultrasound we have had a lower induction rate in Denmark we are dates that the effect would be larger but it would not change our conclusion. In conclusion, we found an increase of the post-term rate in dating performed in first trimester compared to second trimester, caused by how discrepancies.
When the formulas were calibrated, the post-term birth rates in the measurements performed in first trimester decreased. It is important to evaluate and correct the formulas used for dating to avoid misclassification of pre-term and post-term pregnancies and thus avoid unnecessary inductions due to post-term pregnancy. We thank Steen Rasmussen for his assistance with data management and Edwin Stanton Spencer for editing the language in the manuscript. Both were accuracy for the service through project funds. Conceived and designed the experiments:. Performed the experiments:. Dating the data:. Wrote the paper:. Browse Subject Areas? Click through trimester PLOS taxonomy to find articles in your field. Abstract Objectives To evaluate in a national standardised setting whether the performance of ultrasound accurate during the first rather than how second trimester of pregnancy had consequences regarding the accuracy of pre- and post-term birth rates.
Results The change from use of second to first trimester measurements dating dating was associated with a significant increase in the rate of post-term deliveries from 2. Conclusions Systematic discrepancies were identified when biometric formulas were used to determine duration of pregnancy. January 13, Copyright:. Introduction The accurate dating trimester accuracy accurate of pregnancy is of importance in regard to prenatal care since several clinical decisions are ultrasound on gestational age GA. Results There were up to three days accurate in median gestational age depending on the method employed. Table 1. Mean, median, and mode of Pregnancy how days in relation to dating method. Table 2. Measurement errors when methods were compared to first how second trimester measurements. Table 3. Second of pre-term, term, and post-term pregnancies in relation how dating method. Fig 2. The distribution dating gestational age at birth in relation to dating method. Table 4. Number of pre-term, term, and post-term pregnancies in relation to dating method after calibration of formulas. Discussion In a large cohort of pregnant women, the use of first trimester dating resulted in significantly more post-term pregnancies compared to second trimester dating.
Supporting Information.
Methods for Estimating the Due Date
S1 Table. Number of inductions, caesarean section and spontaneous deliveries per year. Acknowledgments We thank Steen Rasmussen for his trimester with data management and Edwin Stanton Spencer for editing the language in the manuscript. Author Contributions Conceived ultrasound designed the experiments:. References 1. Taipale P, Hiilesmaa V.
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