Table 1. Percentiles of uterine cervical length (mm) using the continuous technique between 18 and 24 weeks of gestation.

Percentiles	Gestational age (weeks)
	18	19	20	21	22	23	24
5	26.0	26.0	31.3	30.0	26.4	27.5	22.0
10	29.0	28.4	33.0	32.0	29.1	31.7	27.0
50	39.0	38.0	39.0	40.0	38.3	38.7	37.3
90	47.2	46.8	49.0	47.5	45.3	46.7	44.9
95	52.6	53.8	56.3	48.7	46.2	47.9	46.8
n	87	91	86	84	83	211	110