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Bjog: An International Journal Of Obstetrics And Gynaecology, Feb 1, 2006
but customised birthweight centiles are complex and the fact that the authors think that they are... more but customised birthweight centiles are complex and the fact that the authors think that they are a tool of prediction shows that they have not fully grasped their own topic. McCowan et al. like us2 used the useful quadrant spread for their data to analyse and compare two different parameters of intrauterine growth restriction. They compared birthweight for gestational age with the complex customised birthweight centiles, which uses computer analysis to take into account maternal variables. Taking into account these maternal variables, one is able to separate out a group of infants who are constitutionally (? genetically) small. McCowan et al. and others have found this group to be at low risk of perinatal morbidity or mortality. In doing so, they have also been able to define another group of growth-restricted infants (customised small for gestational age [SGA]) who are at significantly higher risk of morbidity and mortality. Interestingly, McCowan et al. found this ‘at-risk’ group to have a significantly lower mean ponderal index and a higher rate of abnormal uterine artery Doppler blood flow studies. In a study of 2500 consecutive deliveries, we found that by comparing birthweight (for gestational age) with ponderal index of term infants in a quadrant analysis, we also could define a group with increased morbidity.2 Our study was relatively small, but Villar et al.,3 in a much larger series (16 850 deliveries), had similar findings. In a latter study of uterine artery Doppler blood flow velocity waveforms in the midtrimester of nulliparous pregnancies, using a quadrant analysis, we found that pregnancies that resulted in infants with a low ponderal index mostly had abnormal uteroplacental Doppler studies, whereas those resulting in low-birthweight infants with a normal ponderal index mostly had normal Doppler studies.4 McCowan et al. found that half the studied pregnancies producing customised SGA infants had abnormal uteroplacental Doppler studies. Thus, their findings would tend to confirm our original findings and indicate that many of these high-risk pregnancies probably result from the failure to develop a normal uteroplacental circulation. McCowan et al. with the complex customised birthweight centiles clarify the important concept of constitutionally small infants with a low perinatal morbidity and mortality. I believe that ponderal index is a simple and thus a more usable method of defining the at-risk group with intrauterine growth restriction. j
Australian & New Zealand Journal of Obstetrics & Gynaecology, Aug 1, 2015
Dear Editor, In response to the article by MacDonald et al., I have an important question to the ... more Dear Editor, In response to the article by MacDonald et al., I have an important question to the authors: How is it that in 2015 an academic article on the biggest risk factor for stillbirth (and perinatal distress) at term; fetal growth restriction (FGR), that the article can completely ignore the most important category of FGR: asymmetrical growth restriction? In a manuscript published by our group in 1991, we found that ponderal index appeared to be a better measure of infants with intrauterine growth problems than birthweight centiles. The similar, but larger, study of Villar et al. in fact showed that the highest rates of perinatal distress at term occurred in subgroup with a normal birthweight but a low ponderal index (Figure 1). They also found that the rates of perinatal distress were all higher in the low ponderal index subgroups than in the low-birthweight subgroups. We went on to publish a review on ‘categories of intrauterine growth retardation’. Far from ‘shining any light’ on the subject, in my opinion, this article, does the opposite.
Bjog: An International Journal Of Obstetrics And Gynaecology, 1999
detection limit, 2 out of 38 women had a false negative test after physiological urinary dilution... more detection limit, 2 out of 38 women had a false negative test after physiological urinary dilution. These women had aquantitative PhCG of 229 and 190, respectively. One of these women had an ectopic pregnancy. To clinicians, a highly sensitive test is essential to allow safe d i s charge of patients as well as unnecessary recourse to quantitative serum PhCG levels, irrespective of pre-testing hydration status. Ikomi et al. suggests that specific gravity should be used in conjunction with pregnancy test kits with poorer detection limits. In a busy unit, this is neither a practical suggestion nor a plausible diagnostic tool. For example, at what specific gravity should one question a negative pregnancy test with a detection limit of 50 IUL? If the results of this study are to be taken at face value, then all units should abandon urinary pregnancy tests with detection limits of 50 IUL and replace them with those with greater sensitivity.
Bjog: An International Journal Of Obstetrics And Gynaecology, Feb 1, 2006
but customised birthweight centiles are complex and the fact that the authors think that they are... more but customised birthweight centiles are complex and the fact that the authors think that they are a tool of prediction shows that they have not fully grasped their own topic. McCowan et al. like us2 used the useful quadrant spread for their data to analyse and compare two different parameters of intrauterine growth restriction. They compared birthweight for gestational age with the complex customised birthweight centiles, which uses computer analysis to take into account maternal variables. Taking into account these maternal variables, one is able to separate out a group of infants who are constitutionally (? genetically) small. McCowan et al. and others have found this group to be at low risk of perinatal morbidity or mortality. In doing so, they have also been able to define another group of growth-restricted infants (customised small for gestational age [SGA]) who are at significantly higher risk of morbidity and mortality. Interestingly, McCowan et al. found this ‘at-risk’ group to have a significantly lower mean ponderal index and a higher rate of abnormal uterine artery Doppler blood flow studies. In a study of 2500 consecutive deliveries, we found that by comparing birthweight (for gestational age) with ponderal index of term infants in a quadrant analysis, we also could define a group with increased morbidity.2 Our study was relatively small, but Villar et al.,3 in a much larger series (16 850 deliveries), had similar findings. In a latter study of uterine artery Doppler blood flow velocity waveforms in the midtrimester of nulliparous pregnancies, using a quadrant analysis, we found that pregnancies that resulted in infants with a low ponderal index mostly had abnormal uteroplacental Doppler studies, whereas those resulting in low-birthweight infants with a normal ponderal index mostly had normal Doppler studies.4 McCowan et al. found that half the studied pregnancies producing customised SGA infants had abnormal uteroplacental Doppler studies. Thus, their findings would tend to confirm our original findings and indicate that many of these high-risk pregnancies probably result from the failure to develop a normal uteroplacental circulation. McCowan et al. with the complex customised birthweight centiles clarify the important concept of constitutionally small infants with a low perinatal morbidity and mortality. I believe that ponderal index is a simple and thus a more usable method of defining the at-risk group with intrauterine growth restriction. j
Australian & New Zealand Journal of Obstetrics & Gynaecology, Aug 1, 2015
Dear Editor, In response to the article by MacDonald et al., I have an important question to the ... more Dear Editor, In response to the article by MacDonald et al., I have an important question to the authors: How is it that in 2015 an academic article on the biggest risk factor for stillbirth (and perinatal distress) at term; fetal growth restriction (FGR), that the article can completely ignore the most important category of FGR: asymmetrical growth restriction? In a manuscript published by our group in 1991, we found that ponderal index appeared to be a better measure of infants with intrauterine growth problems than birthweight centiles. The similar, but larger, study of Villar et al. in fact showed that the highest rates of perinatal distress at term occurred in subgroup with a normal birthweight but a low ponderal index (Figure 1). They also found that the rates of perinatal distress were all higher in the low ponderal index subgroups than in the low-birthweight subgroups. We went on to publish a review on ‘categories of intrauterine growth retardation’. Far from ‘shining any light’ on the subject, in my opinion, this article, does the opposite.
Bjog: An International Journal Of Obstetrics And Gynaecology, 1999
detection limit, 2 out of 38 women had a false negative test after physiological urinary dilution... more detection limit, 2 out of 38 women had a false negative test after physiological urinary dilution. These women had aquantitative PhCG of 229 and 190, respectively. One of these women had an ectopic pregnancy. To clinicians, a highly sensitive test is essential to allow safe d i s charge of patients as well as unnecessary recourse to quantitative serum PhCG levels, irrespective of pre-testing hydration status. Ikomi et al. suggests that specific gravity should be used in conjunction with pregnancy test kits with poorer detection limits. In a busy unit, this is neither a practical suggestion nor a plausible diagnostic tool. For example, at what specific gravity should one question a negative pregnancy test with a detection limit of 50 IUL? If the results of this study are to be taken at face value, then all units should abandon urinary pregnancy tests with detection limits of 50 IUL and replace them with those with greater sensitivity.
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