Taking account of vaginal bleeding in screening for Down's syndrome

Abstract

Objective To derive a method for revising the risk of Down's syndrome in maternal serum marker screening when there is vaginal bleeding. The effect on screening performance of routinely allowing for the presence or absence of bleeding in all women is also assessed. Design Overview of published studies on the rate of reported vaginal bleeding in pregnancies with Down's syndrome, on the rate according to maternal age and on the association of bleeding with alpha‐fetoprotein (AFP) level. The publications are supplemented with data on unconjugated oestriol (uE3), human chorionic gonadotrophin (hCG) and AFP levels in a consecutive series of screened women. Setting Routine Down's syndrome screening tests carried out on women having antenatal care at the St James's University Hospital, Leeds. Subject Eight hundred and nine screened women. Results In five studies the rate of vaginal bleeding in Down's syndrome pregnancies was 1.7 times that in unaffected pregnancies on average. In three studies, the vaginal bleeding rate increased proportionally by 2.2 % on average for each year of maternal age. Three studies and our own data were consistent with a 10% increase in the mean AFP level associated with vaginal bleeding, but it did not appear to materially alter uE3 and hCG levels or the standard deviations and correlation coefficients for any of the three analytes. An individual woman's risk was calculated by multiplying her age‐specific odds of Down's syndrome by two likelihood ratios, one relating to the vaginal bleeding itself and one from the marker levels. Routine allowance for the presence or absence of vaginal bleeding was estimated to increase the detection rate by less than 1%. Conclusion Our method is of clinical value in revising the risk when there is concern that vaginal bleeding might be responsible for a negative maternal serum Down's syndrome screening result. A policy of routinely incorporating information on vaginal bleeding in risk estimation for all women would have too small an effect on overall screening performance to recommend it.

Does vaginal bleeding influence first‐trimester markers for Down syndrome?

“…However, comparison of the subgroups of patients with early vaginal bleeding to patients without bleeding showed no significant difference in δ-NT, the MoM's of free β-hCG and PAPP-A. This is in contrast to the effect of early vaginal bleeding on the maternal serum concentrations of αfetoprotein in the first and second trimester of pregnancy (Haddow et al, 1986;Bernstein et al, 1992;Williams et al, 1992;Cuckle et al, 1994;Berry et al, 1995). Our results are in line with those reported by De Biasio et al (2003), who found higher maternal serum levels of free β-hCG in the first trimester after early vaginal bleeding.…”

“…Some kind of vascular disruption at the maternal-fetal interface may be the cause for bleeding to occur. Such an event is likely to affect the maternal serum concentration of proteins produced by the placenta and the fetus, including those used for Down syndrome screening (Cuckle et al, 1994).…”

“…In fact, vaginal bleeding is well known to affect maternal serum concentrations of α-fetoprotein in the first (Berry et al, 1995) and second trimester (Haddow et al, 1986;Bernstein et al, 1992;Williams et al, 1992;Cuckle et al, 1994) of pregnancy, and possibly those *Correspondence to: J. Heinig, Department of Obstetrics and Gynaecology, University of Münster, D-48129 Münster, Albert-Schweitzer-Strasse 32, Germany. E-mail: heinig@uni-muenster.de of free β-hCG in the first trimester (Berry et al, 1995).…”

Outcome of Pregnancies Having Bleeding Pervagina in the First Trimester

“…17 The incidence of vaginal bleeding in pregnancies with Down's syndrome was about 1.7 times more than the unaffected pregnancies. 18 But most of the studies concluded that there was no excess of congenital anomalies of the foetus after vaginal bleeding in first trimester.…”

The Effect of Vaginal Bleeding on Parameters Used in the First Trimester Fetal Aneuploidy Screening Test

“…Vajinal kanamanın etiyolojisi tam olarak aydınla-tılmamıştır fakat en önemli nedenlerinden biri maternal-fetal yüzdeki desidual damarların ayrılma-sıdır (6,7). Daha önce yapılan çalışmalarda maternal serum Alfa -fetoprotein (AFP) düzeylerinin vajinal kanamadan etkilenebileceği gösterilmiştir (8)(9)(10) . Ayrıca vajinal kanama öyküsü olan hastalarda bazı çalışma-larda serum serbest β-hCG seviyelerinde ve PAPP-A seviyelerinde yükseklik saptanmış olup (11,12) , serum seviyelerinin etkilenmediğini de gösteren çalışmalar mevcuttur (13) .…”