Hum. Reprod. Advance Access originally published online on May 8, 2009
Human Reproduction 2009 24(8):1825-1833; doi:10.1093/humrep/dep176
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Age determination enhanced by embryonic foot bud and foot plate measurements in relation to Carnegie stages, and the influence of maternal cigarette smoking
1 Laboratory of Reproductive Biology, The Juliane Marie Centre for Women, Children and Reproduction, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark 2 Department of Obstetrics & Gynaecology, Frederiksberg Hospital, Faculty of Health Sciences, Copenhagen University, Copenhagen, Denmark 3 Department of Obstetrics & Gynaecology, Herlev Hospital, Faculty of Health Sciences, Copenhagen University, Copenhagen, Denmark
4 Correspondence address. Laboratory of Reproductive Biology, section 5712, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, DK-2100 Copenhagen, Denmark. Tel: +45-35455830; Fax: +45-35455824; E-mail: melissa.lutterodt{at}rh.regionh.dk
BACKGROUND: Reliable age determination of first-trimester human embryos and fetuses is an important parameter for clinical use and basic science. Age determination by ultrasound or morphometric parameters of embryos 4–6 weeks post conception (p.c.) have been questioned, and more accurate methods are required. Data on whether and how maternal smoking and alcohol consumption influence embryonic and fetal foot growth is also lacking.
METHODS: Embryonic tissue from 102 first-trimester legal abortions (aged 35–69 days p.c.) were collected. All women answered a questionnaire concerning smoking and drinking habits, and delivered a urine sample for cotinine analysis. Embryonic age was evaluated by vaginal ultrasound measurements and by post-termination foot length and compared with the Carnegie stages.
RESULTS: Foot bud and foot plate were defined and measured as foot length in embryos aged 35–47 days p.c. (range 0.8–2.1 mm). In embryos and fetuses aged 41–69 days p.c., heel-toe length was measured (range 2.5–7.5 mm). We found a significant linear correlation between foot length and age. Morphology of the feet was compared visually with the Carnegie collection, and we found that the mean ages of the two collections correlated well. Foot length was independent of gender, Environmental Tobacco Smoke, maternal smoking and alcohol consumption.
CONCLUSION: Foot length correlated linearly to embryonic and foetal age, and was unaffected by gender, ETS, maternal smoking and alcohol consumption.
Key words: foot length/first-trimester/embryonic age/fetus/smoking
Submitted on December 9, 2008; resubmitted on April 3, 2009; accepted on April 9, 2009.