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Fetal crown‐rump length values in the first trimester based upon ovulation timing using the luteinizing hormone surge
Author(s) -
EVANS J.
Publication year - 1991
Publication title -
bjog: an international journal of obstetrics and gynaecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.157
H-Index - 164
eISSN - 1471-0528
pISSN - 1470-0328
DOI - 10.1111/j.1471-0528.1991.tb10310.x
Subject(s) - ovulation , luteinizing hormone , obstetrics , gestational sac , gynecology , medicine , gestational age , gamete intrafallopian transfer , infertility , crown rump length , pregnancy , fetus , hormone , biology , endocrinology , first trimester , genetics
Summary. Fetal crown rump length (CRL) was measured weekly in 33 singleton pregnancies that were established after in vitro fertilization, gamete intrafallopian transfer or natural intercourse in monitored infertility treatment cycles. The time of the luteinizing hormone surge or hCG administration was known for all of them. There was no difference in CRL between the different infertility treatment groups. CRL measurements from this and a similar study where gestational age had been based on the time of ovulation were compared with the CRL measurements from pregnancies where the gestational age had been calculated from the last menstrual period. The CRL was found to be generally smaller in the studies based on ovulation timing and the difference was statistically significant at one time point. This suggests that there is a need for a gold standard in obstetric ultrasound, measurements being based on the gestational age as calculated from the unequivocal date of conception, rather than the last menstrual period.