Dear Belinda
A colleague, Joan Lalor, and I have briefly looked at the area of use
and interpretation of preterm CTGs and below is part of a draft paper,
which might be of use. Additionally, I include other references that
may help.
The evidence consistently demonstrates known differences in fetal
behavioural states in response to cardiovascular and central nervous
system influences associated with gestational age.(Cibis, 1996) The
correlation, for example, between fetal movements, fetal heart
accelerations and fetal wellbeing seen in the non-stress test (NST)
later in pregnancy is not readily recognisable in fetuses of less than
32 weeks gestation.(Natale, Nasello, & Turliuk, 1984) In addition,
gestational age influences fetal responses to stressful
conditions(Cibils, 1977) and as NST parameters vary with fetal maturity,
ominous fetal heart patterns associated with fetal distress in the term
infant may not have the same predictive value in immature
fetuses(Westgren, Holmqvist, Svenningsen, & Ingemarsson, 1982).
Such important known differences in gestational age and dependent fetal
responses have important clinical implications.(Park, Hwang, Cha, Park,
& Koh, 2001 {Cibis, 1996 #159)
Cibils, L. A. (1977). Clinical significance of fetal heart rate patterns
during labor. IV. Agonal patterns. American Journal of Obstetrics &
Gynecology, 129(8), 833-844.
Cibis, L. A. (1996). On Intrapartum Fetal Monitoring. American Journal
of Obstetrics & Gynecology, 174(4), 1382-1389.
Natale, R., Nasello, C., & Turliuk, R. (1984). The relationship between
movements and accelerations in fetal heart rate at 24 to 32 weeks'
gestation. American Journal of Obstetrics & Gynecology, 148, 591-595.
Park, M. I., Hwang, J. H., Cha, K. J., Park, Y. S., & Koh, S. K. (2001).
Computerized analysis of fetal heart rate parameters by gestational age.
International Journal of Gynaecology & Obstetrics., 74(2), 157-164.
Westgren, M., Holmqvist, P., Svenningsen, N. W., & Ingemarsson, I.
(1982). Intrapartum fetal monitoring in preterm deliveries: prospective
study. Obstetrics & Gynecology, 60, 99-106.
OTHER REFS
Aladjem, S., Vuolo, K., Pazos, R., & Lueck, J. (1981). Antepartum fetal
testing: evaluation and redefinition of criteria for clinical
interpretation. Semin Perinatol, 5, 145-154.
Bowes, W. A., Gabbe, S. G., & Bowes, C. (1980). Fetal heart rate
monitoring in premature infants weighing 1500 grams or less. American
Journal of Obstetrics & Gynecology, 137, 791-795.
Burrus, D. R., O'Shea, T. M., Jr., Veille, J. C., & Mueller-Heubach, E.
(1994). The predictive value of intrapartum fetal heart rate
abnormalities in the extremely premature infant. American Journal of
Obstetrics & Gynecology., 171(4), 1128-1132.
Castillo, R. A., Devon, L. D., Arthur, M., Searle, N., Metheny, W. P., &
Ruedrich, D. A. (1989). The preterm nonstress test: Effects of
gestational age and length of study. 160, 172-175.
Dawes, G. S., Moulden, M., & Redman, C. W. (1996). Improvements in
computerized fetal heart rate analysis antepartum. Journal of Perinatal
Medicine., 24(1), 25-36.
Druzin, M. L., Fox, A., Kogut, E., & Carlson, C. (1985). The
relationship of the nonstress test to gestational age. American Journal
of Obstetrics & Gynecology, 156, 386-389.
Druzin, M. L., Hutson, J. M., & Edersheim, T. G. (1986). Relationship of
baseline fetal heart rate to gestational age and fetal sex. American
Journal of Obstetrics & Gynecology, 154(5), 1102-1103.
Eden, R. D., Seifert, L. S., Frese-Gallo, J., Bartasius, V., & Spellacy,
W. N. (1987). Effect of gestational age on baseline fetal heart rate
during the third trimester of pregnancy. Journal of Reproductive
Medicine., 32(4), 285-286.
Gagnon, R., Campbell, K., Hunse, C., & Patrick, J. (1987). Patterns of
human fetal heart rate accelerations from 26 weeks to term. 157,
743-748.
Ibarra-Polo, A. A., Guiloff, E., & Gomez-Rogers, C. (1972). Fetal heart
rate throughout pregnancy. American Journal of Obstetrics & Gynecology,
113, 814-818.
Killien, M. G., & Shy, K. (1989). A randomized trial of electronic fetal
monitoring in preterm labor: mothers' views. Birth, 16, 7-12.
Koyanagi, T., Nakahara, H., Hori, E., Hara, K., & Nakano, H. (1988). A
mathematical model for analyzing beat-to-beat difference in the human
fetal heart rate during gestation and labor. International Journal of
Bio-Medical Computing., 22(1), 29-37.
Low, J. A., Galbraith, R. S., Muir, D. W., Killen, H. L., Pater, E. A.,
& Karchmar, E. J. (l992). Mortality and morbidity after intrapartum
asphyxia in the preterm fetus. Obstetrics & Gynecology, 80, 57-56l.
Low, J. A., Panagitopoulos, C., & Derrick, E. J. (1995). Newborn
complications after intrapartum asphyxia with metabolic acidosis in the
pre term fetus. American Journal of Obstetrics & Gynecology, 172,
805-810.
Natale, R., Nasello, C., & Turliuk, R. (1984). The relationship between
movements and accelerations in fetal heart rate at 24 to 32 weeks'
gestation. American Journal of Obstetrics & Gynecology, 148, 591-595.
Navot, D., Yaffe, H., & Sadovsky, E. (1984). The ratio of fetal heart
rate accelerations to fetal movements according to gestational age. 149,
92-94.
Nicolaides, K. H., Sadovsky, G., & Visser, G. H. (1989). Heart rate
patterns in normoxemic, hypoxemic, and anemic second-trimester fetuses.
American Journal of Obstetrics & Gynecology., 160(5 Pt 1), 1034-1037.
Pillai, M., & James, D. (1990). The development of fetal heart rate
patterns during normal pregnancy. Obstetrics & Gynecology., 76(5 Pt 1),
812-816.
Prietsch, V., Knoepke, U., & Obladen, M. (1994). Continuous monitoring
of heart rate variability in preterm infants. Early Human Development.,
37(2), 117-131.
Snijders, R. J., McLaren, R., & Nicolaides, K. H. (1990).
Computer-assisted analysis of fetal heart rate patterns at 20-41 weeks'
gestation. Fetal Diagnosis & Therapy., 5(2), 79-83.
Sorokin, Y., Dierker, U., Pillay, S. K., & et al. (1982). The
association between fetal heart rate patterns and fetal movements in
pregnancies between 20 and 30 weeks' gestation. American Journal of
Obstetrics & Gynecology, 143, 243-249.
Visser, G. H., Sadovsky, G., & Nicolaides, K. H. (1990). Antepartum
heart rate patterns in small-for-gestational-age third-trimester
fetuses: correlations with blood gas values obtained at cordocentesis.
American Journal of Obstetrics & Gynecology., 162(3), 698-703.
Wheeler, T., & Murrills, A. (1978). Patterns of fetal heart rate during
normal pregnancy. British Journal of Obstetrics & Gynaecology, 85,
18-27.
Declan
Declan Devane,
Doctoral Student / Midwifery Research Assistant,
School of Nursing and Midwifery Studies,
University of Dublin Trinity College,
Trinity Centre for Health Sciences Education,
St. James's Hospital,
Dublin 8.
Tel: 087 659 6923
Email: [log in to unmask]
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-----Original Message-----
From: A forum for discussion on midwifery and reproductive health
research. [mailto:[log in to unmask]] On Behalf Of Gloria
Lankshear
Sent: 03 October 2003 11:11
To: [log in to unmask]
Subject: Re: Antenatal CTGs
Hi Belinda,
I am a researcher looking at decision support systems in the medical
field and have just come across a system that Oxford Instruments have
designed. They are just sending me a draft of a booklet they are
producing about the system which from what I can deduce helps to
interpret antenatal CTGs. So it might be of interest to you. It is based
on Dawes/Redman work, and uses computer stored data to help in
interpretation. That is all I know about the system but I thought it
might be of interest to you.
Best wishes, Gloria
-----Original Message-----
From: Belinda Cox [mailto:[log in to unmask]]
Sent: 02 October 2003 19:22
To: [log in to unmask]
Subject: Antenatal CTGs
Apologies for cross posting.
I'm interested to know the criteria other units use for 'diagnosing'
CTGs done in the antenatal period. To explain what I mean, the NICE EFM
guideline defines what is 'normal', 'suspicious' and 'pathological', but
this guideline only relates to term pregnancies when the woman is in
labour.
How do we 'diagnose' what is normal or otherwise in a CTG done, for
example, at 34 weeks? Do other units use similar criteria limits on
things such as baseline, variability etc, for these CTGS, or do you
have different limits?
Does anyone know of any evidence to back up NICE's or an individual
unit's criteria for non-labouring CTGs?
Many thanks,
Belinda
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