Gudicha DW, Romero R, Kabiri D, et al. - For preterm birth, a sonographic short cervix length (< 25 mm during mid-gestation) is reported to have the most powerful predictive value. Current clinical practice assumes that in all women, the same cervical length cut-off value should be applied when screening for spontaneous preterm birth, despite the possibility of this approach being suboptimal. Researchers sought to create a customized cervical length standard that considers relevant maternal characteristics and gestational age at sonographic examination and investigated if the prediction of spontaneous preterm birth improves with customization of cervical length evaluation. In this retrospective analysis, a cohort of 7,826 pregnancies were assessed. Until 20 weeks of gestation, the median cervical length remained fundamentally unchanged and subsequently reduced non-linearly with advancing gestational age among women who delivered at term. The gestational age at ultrasound scan was identified influencing the effects of parity and maternal weight and height on the cervical length. Relative to nulliparas, parous women had a longer cervix, and increase in the difference was noted with advancing gestation after adjusting for maternal weight and height. Similarly, there was non-linear association of maternal weight with a longer cervix, and greater effect later in gestation. Relative to using cervical length < 25mm, a customized cervical length assessment results in identification of more women at risk for spontaneous preterm delivery and improvement in the differentiation between patients at risk for impending preterm delivery in those who have an episode of preterm labor.