Here is a link to a study that shows how hard it it the find the
exact same measurement even by the same practitioner
http://www.pubmedcentral.nih.gov/pa...ageindex=2
Normal variation of fundal height
http://www.mayoclinic.com/health/fundal-height/AN01628
Also interesting:
http://www.journals.elsevierhealth....7/abstract
Fundal height not always compatible with dates
http://parenting.ivillage.com/pregn...qg,00.html
http://www.fetal.com/IUGR/diagnosed.html
Personally, I would not even worry with a 3 cm difference at any
given point in the pregnancy, unless the weight gain and growth
remain low in consecutive visits.
http://emedicine.medscape.com/article/261226-overview
Screening for IUGR in the general population relies on
symphysis–fundal height measurements. This is a routine
portion of prenatal care from 20 weeks' until term. Although recent
studies have questioned the accuracy of fundal height measurements,
particularly in obese patients, a discrepancy of greater than 3
cm between observed and expected measurements may prompt
a growth evaluation using ultrasound (Jelks et al).[script
removed]9 The clinician should be aware that the sensitivity
of fundal height measurement is limited, and he or she should
maintain a heightened awareness for potential growth-restricted
fetuses. In an unselected hospital population, only 26% of fetuses
that were SGA were suggested to be SGA based on clinical
examination findings.
One study using fundal height curves that customized for
maternal weight, height, and ethnicity was able to increase the
detection rate from 29.2% in the control group to 47.9% in the
study population. As Yoshida et al indicated, these inaccuracies
occur (1) because of the limited accuracy of predicting birth
weight within 10% using ultrasonography in the third trimester, (2)
because not all fetuses that are SGA have IUGR, (3) because
individual and unpredictable changes in growth potential occur, and
(4) because growth distribution is a continuum.[script
removed]10
To follow up on that, if a scan is performed with a 2 cm
discrepancy in fundal height:
http://www.aims.org.uk/Journal/Vol10No3/resaut98.htm#2
So then, if IUGR is expected with a 1cm discrepancy, and a scan
is performed and a management protocol is based on consecutive US,
it seems to me that the possibility of this setting a woman up for
a c-section early in pregnancy ishigh.
Just some information I gathered. I haven't needed to
substantiate this in a long time as it seems to be a commonly
accepted pratice to not worry about a 2-3 cm difference between
gestational age and pubi-fundus measurement. 3 cm is really not
that much and can be influenced by a lot of variables.
That said, I was always totally spot on. With all 4 babies!!!
However, I know many women who have never been consistent. but
seriously, 1cm difference? That reaks of over management.
[script removed]