Those things about pregnancy and childbirth: polyhydramnios and oligohydramnios

Where does amniotic fluid come from?

Amniotic fluid is not ordinary water, It is essential for the normal growth and development of the fetus, And there are also some people about the source of amniotic fluid, It may surprise you to say it, In fact, after entering the second trimester of pregnancy, The main source of amniotic fluid is fetal urine, Another secondary source is fluid secreted by the fetal lungs. In the third trimester of pregnancy, The fetus can produce more than 1000 mL of urine per day, There must be a way out for so much amniotic fluid, Otherwise, it will lead to polyhydramnios. The main way of amniotic fluid absorption is fetal swallowing. To put it bluntly, How do you have to drink it], It makes sense not to defecate anywhere. If the fetus [defecates] in the uterus, You have to swallow it together with your urine. But don’t get too tangled up, Fetal urine and meconium are relatively clean, amniotic fluid also has antibacterial effect. Another secondary absorption route of amniotic fluid is blood vessels on the placenta surface. The function of amniotic fluid amniotic fluid can provide a space for the fetus to move, which is very important for the development of fetal musculoskeletal system. It is also important for the fetus to swallow amniotic fluid normally for the development of its gastrointestinal tract. Amniotic fluid can also provide a constant temperature protection environment for the fetus, To protect the fetus from direct pressure from the uterus, As well as protecting the fetus from injury when the pregnant woman’s abdomen is impacted. Amniotic fluid also has another special bacteriostatic function. The chance of fetal intrauterine infection is reduced. Amniotic fluid volume cannot be directly measured clinically for polyhydramnios. The commonly used auxiliary method for judging amniotic fluid volume is ultrasound examination. If a single maximum amniotic fluid volume is used as the standard, more than 8 cm is polyhydramnios. If the amniotic fluid index (AFI) is used, The four quadrants of amniotic pools add up), More than 25 is polyhydramnios. The incidence of polyhydramnios is 1-2%, The most common causes are fetal abnormalities, twins and diabetes. The most common fetal abnormalities associated with polyhydramnios include central nervous system abnormalities (e.g. Anencephaly) and digestive tract abnormalities (e.g. Esophageal atresia). Duodenal atresia). When polyhydramnios occurs, The most important thing is to find out why, Including further detailed fetal structure examination by ultrasound experts, MRI examination and fetal chromosome examination are performed when necessary. Even if a comprehensive and detailed examination is performed, There are still about 70% of polyhydramnios whose causes cannot be found. Serious complications of polyhydramnios include premature rupture of membranes, premature delivery, placental abruption, postpartum hemorrhage caused by uterine atony, etc. If there is no other mother and fetus to testify, Amniotic fluid excess does not require intervention in most cases. If the amniotic fluid volume increases significantly in the short term, If the mother is seriously unwell and has difficulty breathing, Amniocentesis can be considered to release amniotic fluid. For most expectant mothers with polyhydramnios, There is no need to worry too much, because the prognosis of babies with polyhydramnios of unknown causes, mild polyhydramnios, and polyhydramnios without fetal malformation is mostly better. Oligohydramnios If a single maximum amniotic pool is used as the standard, ≤ 2 cm is oligohydramnios; If the amniotic fluid index (AFI) is used, ≤ 5 is oligohydramnios. The incidence rate of oligohydramnios is 1-2%, The most common causes are fetal abnormalities (mainly kidney dysplasia) and decreased fetal urine output (often accompanied by fetal growth and development retardation) caused by placental dysplasia. Compared with polyhydramnios, Oligohydramnios-related adverse perinatal fetal prognosis incidence rate is higher, including fetal malformation, premature delivery, stillbirth, fetal lung dysplasia, etc. In terms of treatment, it is mainly to find the cause of the disease, strengthen monitoring, and terminate pregnancy in time when necessary. Some foreign medical institutions will do amniotic cavity fluid perfusion, prolong gestational weeks, reduce complications, and do less in China.