Lunar cycle and fetal nuchal translucency in the first trimester of pregnancy

We hypothesized that the moon may have an effect on fetal circulation and the amount of fluid behind the fetus' neck in the first trimester of pregnancy. In the present study we investigated whether lunar position influences nuchal translucency thickness at first trimester screening for chromosomal abnormalities. The data of 1023 consecutive singleton fetuses measured between 11 + 0 and 13 + 6 gestational weeks at the four key lunar positions across 63 lunar cycles were retrospectively analyzed. To correct for gestational variation in nuchal translucency thickness, measurements were expressed as the difference from the normal median nuchal translucency at the measured crown rump length (Delta-NT). No significant difference between the mean Delta-NT at four key lunar positions (new moon, full moon, first quarter, last quarter) was found. There was also no significant difference between the mean Delta-NT on days with spring tide (new moon/full moon) and neap tide (first quarter/last quarter). Although effects of the moon on human physiology have been suggested, the moon does not seem to influence nuchal translucency thickness.