Australian and New Zealand Journal of Obstetrics and Gynaecology 2014; 54: 600–602

Letters to the Editor First trimester maternal serum markers of aneuploidy and the risk of intrapartum fetal compromise We read with much interest the article by Prior et al.1 The study investigates whether first trimester b-hCG and PAPP-A levels are predictive of intrapartum fetal hypoxia or haemodynamic fetal disorders at term in a low-risk selected population. The issue is extremely important, since fetal compromise during labour represents a matter of debate both in the setting of the delivery room and in case of medical– legal litigation. The study by Prior et al. is well designed and concludes that there is no association between PAPP-A or b-hCG levels and the incidence of caesarean section for fetal hypoxia during labour. These findings are in contrast with previous articles, describing a link between first trimester serum markers and the risk of intrapartum fetal compromise.2,3 As correctly pointed out in the title and throughout the article, one of the major characteristics of the analysis by Prior et al. is that a very low-risk population of normal pregnancies was included in the analysis. This strict selection of cases is likely responsible for the limited number of women with low PAPP-A levels included (N = 34) and for the high mean level of PAPP-A detected during first trimester (1.10 MoM). Another condition which possibly influences the results of the study is the high rate of caesarean section in the low-risk population considered (26.9%). Even more importantly, the percentage of abdominal deliveries for presumed fetal compromise appears quite high (11.7%); if we combine these figures with the 18.5% of instrumental deliveries for fetal compromise (while only 39.8% of women achieved spontaneous vaginal delivery), we can assume that several unnecessary interventions were performed on these highly selected women with normal pregnancies, with obvious consequences on the absolute value of umbilical artery pH at birth. It would be of extreme interest if the authors combined data from caesarean and instrumental deliveries performed for fetal compromise, relating their pooled incidence with the first trimester levels of PAPP-A and b-hCG. In a previous study performed by our group on the same issue,2 we did not exclude cases of hypertensive disorders of pregnancy or intra-uterine growth restriction, and we found that decreased PAPP-A levels at first trimester are independently associated with low pH at birth and higher risk of caesarean section for nonreassuring fetal status during labour. The differences between the two studies can be easily explained by the different selection criteria used.

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The considerations expressed in the present letter do not invalidate the conclusions by Prior et al. It is likely that intrapartum outcomes of normally growing fetuses with adequate placentation are not influenced by the levels of PAPP-A at the first trimester. However, this represents an ideal fetal condition, not reflecting the everyday real situation of a high-volume delivery ward. It would be interesting to include in future research all euploid fetuses with low PAPP-A levels and then stratifying at a subsequent time for the presence or absence of obstetric complications such as hypertensive disorders or fetal growth restriction, in order to obtain a deeper insight in this interesting and stimulating field. Stefano UCCELLA and Giacomo F. COLOMBO Department of Obstetrics and Gynecology, University of Insubria, Piazza Biroldi 1,Varese 21100, Italy E-mail: [email protected] DOI: 10.1111/ajo.12284

References 1 Prior T, Mullins E, Bennett P, Kumar S. Are 1st-trimester b-human chorionic gonadotrophin and pregnancy-associated plasma protein A levels predictive of intrapartum fetal compromise in a selected normal population? Aust N Z J Obstet Gynaecol 2014; 54: 418–423. 2 Uccella S, Colombo GF, Bulgheroni CM et al. Firsttrimester maternal serum screening and the risk for fetal distress during labor. Am J Obstet Gynecol 2009; 201: 166.e1–6. 3 Obiekwe B, Chard T. Human chorionic gonadotropin levels in maternal blood in late pregnancy: relation to birthweight, sex and condition of the infant at birth. Br J Obstet Gynaecol 1982; 89: 543–546.

Re: Are 1st-trimester beta-human chorionic gonadotrophin and pregnancy-associated plasma protein A levels predictive of intrapartum fetal compromise in a selected normal population? We read with interest the comments on our recent manuscript.1 The readers commented that the rate of caesarean section, particularly that for presumed fetal compromise, was high. The overall caesarean section rate in the study cohort was 26.9%. However, this is comparable to both the background rate at our institution and that of England and Wales as a whole.2 Whilst the study population was a selected low-risk population, it was composed predominantly of primiparous women, a fact

© 2014 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists The Australian and New Zealand Journal of Obstetrics and Gynaecology

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First trimester maternal serum markers of aneuploidy and the risk of intrapartum fetal compromise.

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