title: Effects of exogenous progesterone on fetal nuchal translucency: an observational prospective study.
abstract: OBJECTIVE
  Nuchal translucency (NT) seen ultrasonographically at 11-14 weeks' gestation is a sensitive marker for Down syndrome. Despite its important role for Down syndrome screening, its use is still considered controversial due to high false-positive rates. We speculated that progesterone could lead to abnormal blood flow patterns and, subsequently, to increased NT. Our primary endpoint was to evaluate the effects of exogenous progesterone on NT thickness compared to controls. The secondary endpoint was to evaluate these effects in a subgroup at low risk for fetal aneuploidies, identifying the strongest factors influencing NT variation. The tertiary endpoint was to evaluate, within the treatment group, if there is any difference in NT according to the type of progesterone administered, route of administration, and dose regimen.
  
  
  METHODS
  All women who came to measure NT at 11-14 weeks' gestation (crown-rump length between 45-84 mm) were considered eligible. We divided patients into 2 groups: women receiving exogenous progesterone and controls. Afterwards, 3 NT scans were performed for each case, and the largest value, accurate to 2 decimal points, was recorded.
  
  
  RESULTS
  In all, 3716 women were enrolled and analyzed. In a crude analysis, NT (P < .05) increased in the exogenous progesterone group. The same results were obtained in the low-risk group (P < .05). The factorial analysis of variance model confirmed a correlation between altered NT and gestational age (P < .0001) and progesterone exposure (P < .05). The characteristics of treatment (route, formulation, dose) were examined separately and no statistically significant differences among the subgroups were observed.
  
  
  CONCLUSIONS
  Exogenous progesterone increases NT.
authors.affiliation: Department of Prenatal Diagnosis, "Altamedica" Fetal-Maternal Medical Center, Rome, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Giorlandino
authors.affiliation: Department of Prenatal Diagnosis, "Altamedica" Fetal-Maternal Medical Center, Rome, Italy.
authors.forename: Pietro
authors.initials: P
authors.lastname: Cignini
authors.affiliation: Department of Prenatal Diagnosis, "Altamedica" Fetal-Maternal Medical Center, Rome, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Padula
authors.affiliation: Scientific Direction Division, Biostatistical Unit, "Regina Elena" Cancer Institute, Rome, Italy.
authors.forename: Diana
authors.initials: D
authors.lastname: Giannarelli
authors.affiliation: Department of Prenatal Diagnosis, "Altamedica" Fetal-Maternal Medical Center, Rome, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: d'Emidio
authors.affiliation: Department of Obstetrics and Gynecology, Campus Bio Medico University of Rome, Rome, Italy. Electronic address: a.aloisi@unicampus.it.
authors.forename: Alessia
authors.initials: A
authors.lastname: Aloisi
authors.affiliation: Department of Obstetrics and Gynecology, Campus Bio Medico University of Rome, Rome, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Plotti
authors.affiliation: Department of Obstetrics and Gynecology, Campus Bio Medico University of Rome, Rome, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Angioli
mesh_terms: D000282:Administration, Intravaginal; D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D004305:Dose-Response Relationship, Drug; D004314:Down Syndrome / Q000175:diagnosis; D005260:Female; D006801:Humans; D007273:Injections, Intramuscular; D016015:Logistic Models; D048208:Nuchal Translucency Measurement / Q000187:drug effects*; D011247:Pregnancy; D011374:Progesterone / Q000008:administration & dosage / Q000494:pharmacology*; D011372:Progestins / Q000008:administration & dosage / Q000494:pharmacology*; D011446:Prospective Studies; D055815:Young Adult
chemical_list: D011372:Progestins; D011374:Progesterone
keywords: aneuploidy; embryo development; nuchal translucency; progesterone; ultrasound