Symphysis-fundus distance
The symphysis-fundus distance (SFA) is an indirect method for the clinical estimation of the size of a fetus . The SFA shows an almost linear increase in the course of pregnancy and correlates proportionally with the crown-rump length .
method
The symphysis-fundus distance is measured with a tape measure from the pubic bone ( symphysis ) to the top of the uterus ( fundus uteri ). The method is not suitable for multiple pregnancies. As a rule of thumb for singleton pregnancies, the following formula can be used:
- Expected SFA = (number of weeks of pregnancy - 10%) ± 3 cm
Example: At 30 weeks of pregnancy a value of (30-3) ± 3 cm is expected, so the fetus should be between 24 and 30 cm tall.
literature
- www.egone.ch, EgoneValidEscript for medical students of the obstetrics course in Basel, Bern, Lausanne and Zurich, script O 11 "Fetal growth retardation"