First-trimester screening for Down syndrome in singleton pregnancies achieved by intrauterine insemination.
OBJECTIVE
To evaluate whether achieving a singleton pregnancy by IUI affects the results of first-trimester screening for Down syndrome compared to naturally conceived pregnancy.


METHODS
Forty-nine IUI and 3059 naturally conceived singleton pregnancies were included in the study. Ovulation in IUI pregnancies was induced by clomiphene and human menopausal gonadotropin. Progesterone was given after insemination for 2 weeks. Down syndrome screening was performed using a combination of maternal age, fetal nuchal translucency, and maternal serum concentrations of free beta-hCG and PAPP-A during the period of 10-14 weeks' gestation.


RESULTS
In IUI pregnancies, nuchal translucency thickness and the levels of PAPP-A were significantly higher. The values of free beta-hCG were not statistically different between the two groups. The screen-positive rate in IUI pregnancies was significantly higher (14.3% vs. 7.1%).


CONCLUSIONS
Singleton pregnancies achieved by IUI have a higher screen-positive rate. Not only elder maternal age but also exogenous hormones given during the process of ovulation induction and after conception may play an important factor influencing positive screening results.
Lai
Tsung-Hsuan
TH
Department of Obstetrics and Gynecology, Taipei Medical Center, Cathay General Hospital, Taipei, Taiwan.
Chen
Su-Chee
SC
Tsai
Ming-Song
MS
Lee
Fa-Kung
FK
Wei
Chi-Feng
CF
D000328:Adult; D001835:Body Weight; D004314:Down Syndrome / Q000175:diagnosis*; D005260:Female; D005820:Genetic Testing; D006801:Humans; D007315:Insemination, Artificial; D008423:Maternal Age; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011296:Prenatal Diagnosis