International conference on the physiology of neonatal transition at birth. University of Birmingham 19th April 2013 link to INTRODUCTION VIDEO

See Opening presentation by Dr Tonse Raju

How can it be safe to suddenly clamp the cord within a few seconds of birth and when it is full of blood
and still circulation 40% of the babies combined cardiac output ?

Learn more below

BMJ article about why cord early cord clamping must stop

Letter about neonatal resuscitation in Archives of Disease in Childhood


Clamping the umbilical cord at birth is not necessary although it has been convenient so that the baby can be removed from its mother before delivery of the placenta, usually 5 to 10 minutes after the birth of the baby. We now clearly recognise that taking the baby away from its mother at birth is harmful to both the baby and the mother. Some years ago it was thought that early cord clamping was an important element in active management of the third stage of labour to prevent post partum haemorrhage. This is now known not to be the case. RCOG Greentop guideline 52 page 4 addendum

ILCOR also recognise just how important it is for the newborn baby to transiton naturally from placetnal respiration to pulmonary respiration. European Resuscitation Guidelines Page 1222Clamping and cutting the cord at birth is an intervention which has no purpose. Withdrawal of such an intervention does not require proof of harm. There is however plenty of evidence of harm ! The latest in a long line of trials showing harm is in a recent BMJ study from Sweden

Why do so many intelligent, caring obstetricians and neonatologists not stop routine cord clamping at birth? Part of it may be complacency. (Some are also very concerned like myself) Many think the harm that cord clamping may do is very minor and pressure of time prevents them from looking into it more carefully. However I will show you that the harm of cord clamping can sometimes be very serious.

Perth (Austrialia) professor tells of serious risks of cord clamping

RCM to recommend delayed cord clamping

International conference on transition and cord clamping at birth April 2013


It is increasingly recognised that the circulatory changes involved in transition at birth cannot occur within a few seconds of birth. While the healthy fetal circulation and the healthy neonatal circulation are moderately well understood, the underlying triggers, the precise sequence and speed of the changes in the circulation are not. (How can we interefere in something we do not understand ?)

Nearly all textbooks and journals which include the physiological transition of the neonate at birth describe a marked change in the peripheral vascular resistance and an increase in the afterload of the heart. One notable exception is Gray's Anatomy. Gray's Anatomy describes inflation of the neonatal lungs as the first change after birth and does not describe any changes in the afterload of the heart. Afterload is the force that the myocardium generates during ejection against systemic and pulmonary vascular resistances. Reductions in afterload increase stroke volume if other variables remain constant. Gray's Anatomy also describe the release of bradykinins from the pulmonary vascular epithelium which are vasoconstrictors to the umbilcal arteries. A high oxygen tension in the blood reaching the umbilcal arteries also has a vasoconstrictor effect on these vessels. Those texts that describe the sudden increase in afterload of the heart, explain that this is the result of withdrawal or closure of the placental circulation. Although Hofmeyer did demonstrate a sudden increase in arterial pressure in the healthy neonate in response to the application of a clamp on the umbilical cord 35 seconds after birth there have been no other investigations of the arterial effects of clamping the umbilical cord. On the other hand the effects of the cord clamp on the venous circulation has been investigated in some detail very recently by Farrar et al showing that sometimes as much as 40% of the neonatal blood volume is permanently trapped in the placenta by early cord clamping.

There is enough understanding of the fetal and neonatal circulation to build a computer simulation and determine whether or not the marked rise in afterload of the heart is likely to occur during a physiological transition. This is what it shows. Although the transition of the neonate has not been well investigated, it occurs successfully in the vast majority of births and has been observed by thousands of midwives. There is no question that a healthy baby will start to breathe soon after birth and the umbilical cord will stop pulsating and become white and empty a few minutes later. In animals it is well established that the high vascular resistance of the fetal lung falls quickly after the lungs are inflated with air. Thus the cardiac output will be partly redirected into the pulmonary circulation when the baby starts to breath and this has the effect of reducing the placental blood flow. (see above) In reality it is likely that the rate of fall in vascular resistance of the lungs will be closely matched by the rate of rise in vascular resistance of the placental circulation. Since the two most clearly understood triggers for closure of the umbilical arteries will not be present in the umbilical arterial blood until the after the lungs start to function. There have been no longitudinal studiesto measure the circulation in the fetus and neonate. In the fetal circulation the right ventricular output (250mls/min/kg) is slighly greater than that of the left. (200mls/min/kg) After transition and closure of the ductus arteriosus the outputs must equalise. How this is achieved by the neonatal heart is not understood and failure to equalise could be a consequence of a sudden increase in afterload at birth. Heart loads are also thought to have a considerable influence on the active adaption of the heart after birth.(18) This model shows no evidence to support the idea that a physiological transition is accompanied by any significant change in the after load of the heart, nor any significant change in the systemic vascular resistance as has been described. Tit shows that there is no need for any change in the cerebral circulation. This is of considerable importance as our investigation indicates that the sudden rise in afterload of the heart is the result of early cord clamping, which will result in a marked increase in the cerebral circulation and in the cerebral vascular pressure. The neonatal brain cannot be expected to cope with a sudden increase in the cerebral blood flow by a factor of 2.2 without some risk of injury. Studies of the venous effects of early cord clamping show the result is hypovolaemia, which can be severe, (10) and will lead to a subsequent fall in cardiac output and fall in cerebral circulation. This could account for the findings of Meyer and Mildenhall (19) who showed a fall in the superior vena cava blood flow (a surrogate measure for cerebral blood flow) in preterm babies who had immediate cord clamping from 20% to 12% of the CCO. Baenziger et al (20) showed a similar fall in cerebral circulation with early cord clamping. Until respiration is well established the pulmonary vascular resistance will remain high leading to a high afterload of the heart. In cases 4,5,6 and 8, after physiological transition, the cerebral blood flow fell from the fetal level by up to 16%. This is the result of the pulmonary circulation taking a greater proportion of the cardiac output in the neonatal model than did the placental circulation before transition. The vascular resistance of the placenta was adjusted in these cases to provide a placental flow down to 20%. Given the importance of maintaining a consistent cerebral circulation this seems an unlikely physiological pattern, but could have implications in intra-uterine growth restriction when the placental blood flow is reduced. Most investigations measured the normal placental blood flow at 40% of the CCO. Simulation might be the only way of demonstrating these marked changes which early cord clamping imposes on the neonatal circulation. Clinical studies of the short and long term consequences of cord clamping have shown evidence of harmful effects on the brain particularly in preterm babies.(21) It would be extremely difficult and may be unethical with the current evidence and guidelines, to carry out direct measurements in the newborn baby. The model indicates that the description of a marked rise in afterload of the heart does not occur in a physiological transition.

video News item

Liverpool Women's support BASICS concept

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Go to OBGYN.net paper on proposal for valid customised charts generation ("Back to the future for Hermanni Boerhaave" published by OBGYN.NET)

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This page's count says this page has been visited  times since 23rd May 1999. All my calculators will work OFF-LINE if you wish. Instructions for use OFF-LINE You are welcome to copy them over. But check for updates from time to time!

LINKS TO

BMJ article on publishing raw data and real time statistical analysis on e-journals

Demonstation of raw data and real time statistical analysis


Northern Region Fetal/Maternal Medicne Special Interest Group Guidelines
Recent BMJ letter regarding DELAYED CORD CLAMPING


OBGYN.NET
Fetal medicine Unit, St Georges, London        Joseph Woo's Ultrasound       The Fetus.net
Correct application of Bayes theorem in estimating sequnetial conditional risk

Go to OBGYN.net paper on proposal for valid customised charts generation ("Back to the future for Hermanni Boerhaave" published by OBGYN.NET)
In the Hermanni Boerhaave story, I am trying to point out that using a scan measurement only provides a measure of the age of the fetus. Another set of data needs then to be applied to provide an estimate of the date of delivery. The true mean (or modal) interval from LMP to delivery may be closer to 282 days rather than the 280 proposed by Boerhaave. By drawing up the charts in the way I have proposed an estimate for the date of delivery is provided directly by the chart, using the same type of data which was used to generate the chart and from no other data. The precise interval from LMP to delivery becomes irrelevant. Not only this, but the data on which the chart is based is relatively free of error. The date of the scan, the scan measurement and the date of delivery are all known. There is another advantage in this method. Because relatively large numbers of secure data can be obtained, we can look for differences that might exist in sub-populations defined by ethnicity, parity, age, fetal sex and maternal size, all of which have been shown to affect the size of the newborn. This is what I showed at the BMFM society meeting in York, Ref1 with a difference of 4.4 days between the two extreme groups. Adding to the database since has made the differences more convincing. 
Although it is possible to draw up a graphic chart using the methodology I have just described, I am not sure that this is a good way to use the data. For dating, there is no need to have the complete range of measurements throughout pregnancy. There are well recognised times when dating by ultrasound is the most accurate. The data from routine ultrasound services is going to be abundant at these times and therefore most confident at the same gestations as ultrasound should be used to provide an accurate EDD. Data for other gestations is unnecessary for dating.
There is an important difference in generating an ultrasound EDD using this methodology from the traditional ultrasound charts. Taking a BPD of say 40 mm, the data shows us that on average the woman will deliver a healthy normal baby after 150 days. Based on a very large population, which is quite feasible, the confidence interval for this could be very narrow. 
With a traditional chart we can see that a baby with a BPD of 40 mm will on average be 130 days gestation. There will always be a range of gestations for each measurement. ( The traditional centile lines on these charts emphasises this point.) This range will be small if the population is large but it is just not feasible to get large numbers of women who are sufficiently secure in their menstrual data. Within this population there will remain a small number of women whose gestation does not relate as expected to their menstrual period. Finally to provide an estimated date of delivery, the interval from LMP still has to be known and this provides room for further error. 
I believe it is this inherent error in traditional ultrasound dating which convinces the majority of obstetricians and midwives that they should favour an integrated use of ultrasound and menstrual dates. CESDI also recommends this approach. Ref2 Widespread adoption of the Boerhaave method for generating the EDD charts could be expected to speed up the general acceptance of pure ultrasound dating. We have recently shown that is really not possible to accurately date or assess growth using a chart and wheel Ref3 and these will always be necessary until we have either universal computerised maternity systems or programmes built into the ultrasound scanners.
References
1. Hutchon DJR. Customised ultrasound dating charts. British Maternal and Fetal Medicine Society. fourth Annual Conference, University of York. Abstartcs - Journal of Obstetrics and Gynaecology 1999 19:suppl 1;s57
2. Hutchon DJR. Routine ultrasound is the method of choice for dating pregnancy. Br J Obstet Gynaecol 1999:106;616
3. Hutchon DJ, et al. Clinical interpretation of ultrasound biometry for dating and for assessment of fetal growth using a wheel and chart: is it sufficiently accurate? Ultrasound Obstet Gynecol. 1999 Feb;13(2):103-6. Copyright 1999, DJR Hutchon. Restricted use is hereby granted (personal OK) so long as this code is not *directly* sold and the copyright notice is buried somewhere deep in your HTML document.

REFERENCES
Smith GCS, Smith MFS, McNay MB and Flemming JEE First-trimester growth and the risk of low birth weight New England Journal of Medicine 1998;339:1817-22

Kurmanavicius J, Wright EM, Royston P, Zimmermann R, Huch R, Huch A, Wisser J. Fetal ultrasound Biometry: 1. Head reference values. British Journal of Obstetrics and Gynaecology. 1999 106:126-135
Kurmanavicius J, Wright EM, Royston P, Zimmermann R, Huch R, Huch A, Wisser J. Fetal ultrasound Biometry: 2. Abdomen and femur length reference values. British Journal of Obstetrics and Gynaecology. 1999 106:136-143
Bergsjo P, Denman III D W, Hoffman H J, Meirik O. Duration of human singleton pregnancy - a population based study. Acta Obstet Gynecol Scand 1990;69:197-207
Altman D G and Chitty L S. New cahrts for ultrasound dating of pregnancy Ultrasound Obstet Gynecol 10 (1997) 174 - 191
Moore T R and Cayle J E. The amniotic fluid index in normal human pregnancy. American Journal of Obstetrics and Gynecology 1990;162:1168-73
Cuckle H S, & Schmi I Calculating correct Down's syndrome risks. British Journal of Obstetrics and Gynaecology 1999;106:371-372
Wald N J, Watt H C, & Hackshaw A K. Integrated screening for Down's Syndrome based on tests performed during the first and second trimester The New England Journal of Medicine 1999;341(7):461-467
Pandya P P, Johnson S, Malligianis P, and Nicolaides K H. First Trimester fetal nuchal translucency and screening for chromosomal abnormalities. Ultrasound and early pregnancy Chapter 7
Cuckle H S, Wald N J, Thompson S G. Estimating a woman's risk of having a pregnancy associated with Down's syndrome using her age and serum alpha-fetoprotein level. Br J Obstet Gynaecol (1987) 94:387-402
Snijders R J M, Holzgreve W, Cuckle H and Nicolaides K H. Maternal age-specific risks for trisomies at 9-14 weeks gestation. Prenatal Diagnosis (1994) 13:543-552 For the purposes of the calculator I have assumed a uniform loss of pregnancy as a result to miscarriage between 9 and 14 weeks and 15 and 20 weeks.
Zosmer N, Souter V L, Chan C S Y, Huggon I C and Nicolaides K H. Early diagnosis of major cardiac defects in chromosomally normal fetuses with increased nuchal translucency. Brtish Journal of Obstetrics and Gynaecology 1999;106:829-833
Morrison J J, Rennie J M, & Milton P J. Neonatal respiratory morbitiy and mode of delivery at term: influence of timing of elective caesarean section. British Jouranl of Obstetrics and Gynaecology 1995 102 101-106
Madar J, Richmond S & Hey E. surfactant deficient respiratory distress after elective delivery at 'term'. Northern Region Maternity Survey Meeting 1999. Accepted for publication in Acta Paediatrica
Hyett J A, Noble P L, Snijders R J M, Montenegro N, & Nicolaides K H. Fetal heart rate in trisomy 21 and other chromosomal abnormalities at 10 - 14 weeks of gestation. Ultrasound Obstet Gynecol 7 (1996) 239-244
I am grateful to Professor Howard Cuckle for information on the Gaussian LR equation for a single variable.
DOWN SYNDROME AGE RISK CALCULATION
This risk assumes no previous affected pregnancy. A previous affected pregnancy increases the risk further, to about 1 in 200 at age 30 and 1 in 25 at age 45.
The maternal age specific incidence of trisomy 21 at birth is 54% lower than at 9-14 weeks of gestation.

LINKS

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Go to OBGYN.net for paper on proposal for valid customised charts generation
Northern Region O&G Trainees website
Go to Fetal weight calculator