The average head and hip length of an eleven-week-old fetus is about 4.0cm. Eleven weeks in the early stage of pregnancy, fetal development is small, at this time the fetal spine has begun to develop, but has not yet formed the physiological curvature, commonly used head and hip length to reflect the size of the fetus, but also help clinical projection of pregnancy weeks, under normal circumstances, eleven weeks of gestation, fetal head and hip length of about 4.0cm. If the head and hip length of the fetus in the eleventh week of pregnancy is obviously lower than the normal standard, at this time, we should check the last menstrual period and the expected date of delivery again, to exclude whether there is a calculation error of the gestational week, in addition to clarify whether there is fetal dysplasia and other conditions; if the head and hip length of the fetus in the eleventh week of pregnancy is obviously higher than the normal value, in addition to checking the gestational week, we should clarify in a timely manner whether there is gestational diabetes mellitus and other diseases, which leads to excessive growth of the fetus. Clinical anomalies occur when necessary, pregnant women need to seek medical treatment under the guidance of a professional physician to avoid delaying the condition, resulting in adverse pregnancy outcomes.