Should we change our mind in biochemical parameters in the second trimester aneuploidy screening test in the patients with polycystic ovary syndrome?Should we change our mind in biochemical parameters in the second trimester aneuploidy screening test in the patients with polycystic ovary syndrome?

Amaç

Polycystic ovary syndrome (PCOS) is a common reproductive and metabolic disorder. Patients with PCOS present with clinical signs of hyperandrogenemia (ie, hirsutism and acne), menstrual irregularities and infertility.

Yöntem

Changes in some enzymatic activities such as 17alphahydroxylase, 17.20-lyase in the ovary and adrenal were showed in PCOS. Malique et al. Also showed that there are differences in activities of some enzymes essantial for placental steroid synthesis in patients with PCOS. They detected lower androstenedione and higher estriol concentrations in female newborns of women with PCOS in the cord blood samples. Estriol is synthesized in the placenta and secreted into the maternal circulation in the second trimester. 16 alpha-hydroxy dehydroepiandrosterone sulphate is formed in the fetal liver by hydroxylation of dehydroepiandrosterone sulphate and transported to the placenta where it undergoes desulphation by steroid sulphatase and aromatization to estriol.

Bulgular

Maternal serum level of unconjugated estriol is lower in Downs syndrome pregnancies than in healthy pregnancies in the second trimester. Serum unconjugated estriol level is used as parameters of second trimester screening test with serum human chorionic gonadotropin and alphafetoprotein. However, the detection rate of the second-trimester screening test for trisomy 21 was reported about 60–70%, with 5% false positive rate. Although second trimester screening test doesn’t have the advantages for early diagnosis in Down Syndrome compared to combined test, it is still used since some of the patients apply firstly in the second trimester. Therefore, quadruple test has started to use for Downs syndrome screening in the second trimester of pregnancy. In addition to triple test parameters, quadruple test includes inhibin-A. However, Segal et al. Found serum inhibin-A concentration in women with PCOS was lower than normal-ovulatory women. In addition, Karsli et al. İnvestigated biochemical parameters in the first trimester aneuploidy screening test in the pregnant women with and without PCOS. They revealed that the biochemical components PAPP-A and fb-hCG were significantly lower in the PCOS group compared with the control group.

Sonuç

In the literature, although there was a study about first trimester aneuploidy screening test to detect Down Syndrome, we could not encounter the study associated with biochemical parameters in the second trimester aneuploidy screening test in patients with polycystic ovary syndrome. We suggest to analyse enzymatic steps in the synthesis of estriol and inhibin-A, serum levels of biochemical parameters in the pregnant women with PCOS. These biochemical parameters are affected also by multiple gestation, in vitro fertilization, maternal weight, ethnicity, smoking and parity. The validated softwares can make adjustments to calculate of Down Syndrome risk for these parameters. PCO should be added among the parameters. 

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