New charts for ultrasound dating of pregnancy

23-Jul-2017 23:07 by 2 Comments

New charts for ultrasound dating of pregnancy

We conclude that commonly used ultrasound reference charts have inaccuracies.We have generated a CRL reference chart based on true gestational age in an IVF cohort that can accurately determine gestational age at 6–9 weeks of gestation.

In these pregnancies with multiple scans, all data were included in the analysis as discrete values.

We examined CRL lengths at 6–9 weeks of gestation measured in a large IVF cohort where gestational age could be calculated from date of fertilisation.

We assessed the ability of six commonly used reference charts to accurately date these pregnancies.

In contrast, dates calculated from the first day of the last menstrual period (menstrual age) may have inaccuracies arising from imprecise recollection of dates, variation in the timing of ovulation, or time to conception.

A number of CRL reference charts have been proposed and different versions are in common use (Table 1).

Given all these charts showed inaccuracies in their ability to date these IVF pregnancies, we developed a new reference chart based on IVF dates in a singleton cohort.

We retrospectively obtained clinical details on 1268 singleton IVF pregnancies conceived using a fresh embryo transfer cycle, had a transvaginal first trimester ultrasound done between 6 ( 1d) to 9 ( 0d) weeks of gestation where CRL were measured, and progressed to viability (24 weeks of gestation).Accurate dating of gestational age is central to good obstetric care.It allows the clinicians to better time gestation-specific antenatal screening tests, reduces erroneous labelling of pregnancies as very preterm, preterm, and small-for-gestational-age, and decreases the risk of inappropriate induction of labour [1–5].It should be possible to generate very accurate reference charts by using a large in vitro fertilisation (IVF) cohort where CRL measurements could be correlated with gestational age precisely calculated from date of fertilisation.Accuracy could be further enhanced by using measurements obtained from high-resolution transvaginal scans by sonologists specialising in Women’s Health.These were identified from a total cohort of 4971 first trimester ultrasound reports of IVF and naturally conceived pregnancy scans.