Maternal smoking, obesity and male fetal sex predispose to a large nuchal translucency thickness in healthy fetuses.
OBJECTIVE
Our aim was to evaluate the effect of fetal sex, smoking and body mass index (BMI) on nuchal translucency (NT).


METHODS
We analyzed data from 7,357 women with a normal singleton live birth outcome with information on smoking, BMI and sex of the infant. NT measurements were converted to multiples of the median (MoM(NT)) using a previously reported linear regression analysis.


RESULTS
The odds ratio (OR) for MoM(NT) >95th centile was 1.5 (95% CI 1.2-1.9) for smokers compared to nonsmokers and 1.4 (95% CI 1.1-1.7) for male fetuses compared to female fetuses. Obese women (BMI ≥30) had an increased OR for a large NT of 1.7 (95% CI 1.2-2.6) compared to normal weight women. Obese smokers carrying a male fetus had an OR of 4.2 (95% CI 1.7-10.1) of a MoM(NT) >95th centile compared to normal weight nonsmoking women with a female fetus. The effects of smoking, obesity status and fetal sex were independent of each other.


CONCLUSIONS
Smoking, obesity and male sex are associated to a MoM(NT) >95th centile. This may affect screening performance and entail unnecessary anxiety in these women. Further investigations, including fetuses with adverse outcome, are needed.
Rode
L
L
Department of Fetal Medicine and Ultrasound, Rigshospitalet and University of Copenhagen, Denmark. linerode @ dadlnet.dk
Ekelund
C
C
Pedersen
N G
NG
Wøjdemann
K R
KR
Christiansen
M
M
Sundberg
K
K
Tabor
A
A
D015992:Body Mass Index; D005260:Female; D047109:Fetal Development; D006801:Humans; D008297:Male; D048208:Nuchal Translucency Measurement; D009765:Obesity / Q000150:complications*; D011237:Predictive Value of Tests; D011247:Pregnancy; D011256:Pregnancy Outcome; D012737:Sex Factors; D012907:Smoking / Q000009:adverse effects*