Although renal colic during pregnancy is uncommon, with a statistical incidence of about 1/2500 to 1/1,500, it is a potentially great problem for pregnant women and can lead to hospitalization, invasive tests and treatment, resulting in side effects for both the pregnant woman and the growing fetus. Renal colic is a severe pain caused by strong spasm of kidney and ureter due to kidney or ureteral obstruction. It mainly manifests as sudden onset and severe pain, which starts from the affected side of the waist along the ureter down the abdomen, groin and inner thigh, often accompanied by nausea and vomiting, profuse sweating and pale face, and can lead to shock in severe cases. It is mostly seen in kidney and ureteral stones, and can also be triggered by hydronephrosis obstruction, etc. Most patients can be relieved by antispasmodic and analgesic treatment, but some patients still have poor results despite the above treatment, recurrent attacks of colic, and can have preterm abortion or complicated by pyelonephritis, and even have to terminate the pregnancy, making the clinical management of these patients more difficult, and its diagnosis and treatment has been controversial. The causes of renal colic during pregnancy are mainly the following: (1) Pregnant women have kidney or ureteral stones before pregnancy, and the obstruction of the kidney and ureter during pregnancy or even the aggravation of the obstruction. (2) Due to the special physiological changes of pregnancy, the excretion of the ureter is slowed down or obstructed, coupled with pregnancy reactions, less water intake and concentration of urine, which can easily produce crystals or sediment and block the kidney and ureter and cause renal colic. (3) Due to the compression of the enlarged uterus and blood vessels and the effect of estrogen, the ureteral drainage is not smooth, and the kidney and ureteral fluid accumulation (medically called physiological hydronephrosis) occurs, causing renal colic. Second, the examination and diagnosis of renal colic occurring during pregnancy There are still some difficulties in the diagnosis of the etiology of renal colic during pregnancy, mainly: intravenous pyelogram (X-ray) and spiral CT are one of the most common and effective examination methods in the diagnosis of urological diseases, but due to the possibility of fetal growth retardation, malformations and childhood tumors, the above examination methods are not used for patients with renal colic combined with pregnancy. MRI lacks validity in the examination of renal colic, is difficult to diagnose small stones, and is expensive. At present, the preferred diagnostic method for pregnancy-associated renal colic is ultrasonography. It is non-invasive, rapid and easy, harmless to human body and does not affect the fetus. However, the long stroke and deep location of the ureter, coupled with intestinal gas and uterine interference, make ultrasound more difficult to show ureteral lesions, and its sensitivity and specificity are reduced, especially in the middle and late stages of pregnancy, and especially difficult for stones in the lower middle part of the ureter. In most cases, ultrasound can only provide indirect evidence, such as whether the upper urinary tract is dilated and the thickness of the renal cortex. Therefore, although a standardized set of diagnostic and therapeutic criteria for kidney stones has been developed over the past decade, there is still some uncertainty in differentiating kidney stones from physiologic hydronephrosis during pregnancy. Encouragingly, there is a growing body of clinical data showing that experienced ultrasonographers can improve the identification of stones or physiologic hydronephrosis through “abnormal findings” in ultrasound Doppler features. Low-dose computed tomography is a highly accurate imaging tool that is increasingly used and has >98% sensitivity and specificity in the diagnosis of urolithiasis in pregnancy with only one-third of the exposure dose of standard CT, short examination time, avoidance of contraindications, and simultaneous detection of other diseases that are not urolithiasis. The treatment of renal colic during pregnancy is still tricky. It is necessary to determine the presence of stones or physiological hydronephrosis, the size of the stones, the degree of pain, whether it is combined with serious infection, and to decide the treatment plan by combining the conditions of the hospital and the level of doctors. For smaller stones (usually less than 8MM in diameter), most patients can be cured by infusion, pain relief, infection prevention, herbal stone removal, etc. For larger stones or patients with severe infection, a drainage tube or even ureteroscopy is needed to remove the stones.