Fetal heart rate in early pregnancy.
Heart rates were measured by transvaginal sonography twice weekly in ten first trimester fetuses in women who conceived after in-vitro fertilization (IVF) or zygote intra-fallopian transfer (ZIFT). From week 6 to week 9 of menstrual age a rapid increase of the mean heart rate was observed from 113 to 167 beats per min, followed by a slow decrease to 156 beats per min. A close correlation between crown-rump length and heart rate was established.
van Heeswijk
M
M
Department of Obstetrics and Gynaecology, University Hospital, Nijmegen, The Netherlands.
Nijhuis
J G
JG
Hollanders
H M
HM
D001827:Body Height; D005260:Female; D005307:Fertilization in Vitro; D005318:Fetal Heart / Q000254:growth & development; D006340:Heart Rate, Fetal; D006801:Humans; D008137:Longitudinal Studies; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D014463:Ultrasonography