Pregnancy: Transvaginal crown—rump length measurements of 224 successful pregnancies which resulted from gamete intra-Fallopian transfer or in-vitro fertilization

Abstract

The crown-rump lengths (CRL) of 224 pregnancies which resulted from gamete intra-Fallopian transfer (GIFT) or in-vitro fertilization (IVF) were assessed two to four times in the first trimester. The results were compared with some of the published articles which assessed CRL in spontaneous and induced pregnancies. The range of CRL measurements from this study was generally smaller than the previously published data, although all women went on to deliver normal fetuses at full term weighing > 2.5 kg. It was not possible to identify a clear reason for this finding, but factors which might have been relevant included population differences, more accurate estimation of ovulation/conception time, the exclusive use of vaginal ultrasonography in this study and variations in the embryonic implantation/development times. There is a need to review the commonly used CRL charts in view of the increasing use of transvaginal ultrasonography and the increasing number of pregnancies with known ovulation/conception times. Each centre should aim to establish the normal CRL range for its own population.

Do specific ultrasonography features identified at the time of early pregnancy loss predict fetal chromosomal abnormality? – A systematic review and meta-analysis

“…However, the evaluation by Carnegie staging system is not commonly used in early pregnancy, and according to the indirect evidence from ultrasound monitoring of intrauterine embryonic size, the embryonic size variation in very early stage of pregnancy is not negligible; whilst after 46 days of embryo development, the fetal sizes in different studies becomes consistent 24, 25. The early embryonic size variation reduced in pregnancies from assisted reproduction with subsequent normal live birth 26, 27. While in general early pregnancy group with unknown outcome, the variation remained obvious 28 .…”

Normal Ranges of Embryonic Length, Embryonic Heart Rate, Gestational Sac Diameter and Yolk Sac Diameter at 6–10 Weeks

“…Although the original formula was derived in 1975 from a study of 334 singleton pregnancies in women with regular menstrual cycles and certain LMP, several subsequent studies have generally confirmed the accuracy of the prediction [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] . Some studies, however, have suggested that in pregnancies below 8 weeks, the measurement of CRL underestimates the GA [17,25] . Studies reporting reference ranges for embryonic HR, GSD or YSD have examined small numbers of either spontaneously conceived pregnancies in women with certain LMP or in vitro fertilisation pregnancies and reported their values either in relation to GA or embryonic CRL [14,18,26, .…”

Pregnancy dating by fetal crown–rump length: a systematic review of charts

“…The searches yielded 1142 citations, of which 62 were considered for potential inclusion (Figure ). Thirty‐three studies were excluded because they described growth with GA ( n = 16), assessed or compared existing chart(s) ( n = 3), were reviews or practice guidelines ( n = 3), or had other aims ( n = 11; Table S2) . Finally, 29 studies providing data on over 11 000 pregnancies met the inclusion criteria and were included in the final analysis (Table ) …”

“…A number of studies reporting CRL measurements in the first trimester have been excluded from this review because they attempted to answer a different question: to describe fetal growth in the first trimester . In some of the studies the authors considered both of these concepts, and such reports were included if GA estimation was one of the stated aims of the study and if a GA estimation formula was provided, regardless of how the data were analysed .…”