What is proteinuria? Why do we do so many urine tests during pregnancy? What are the risks of high proteinuria in pregnant women? The latest on proteinuria during pregnancy.

When pregnant, it is necessary to perform a monthly urine analysis, in particular to ensure that the protein level is not higher than 300 mg/l. This is called proteinuria or albumin . If this is the case, it may simply be a sign of a urinary tract infection. But proteinuria can also be used to detect possible preeclampsia, or toxemia of pregnancy, which requires appropriate medical care.

Proteinuria refers to the “abnormal” presence of proteins in the urine. Usually, urine does not contain proteins, because they are filtered upstream by the kidneys. The presence of proteins in the urine therefore means that the kidneys are no longer able to fulfill their role as filters. “  A high protein level in the urine proves that there is damage to the liver or kidney enzymes  ,” confirms Tiphanie Larue, a private midwife. However, it is not only kidney damage that can cause proteinuria: a urinary tract infection , hypertension or diabetes can also cause the presence of proteins in the urine. “  A metabolic problem, with renal filtration, can also cause the appearance of edema  ,” warns the specialist.

The best known protein found in urine is albumin . We speak of albuminuria to designate an excess of albumin in the urine, and a fortiori to evoke proteinuria.

According to Tiphanie Larue, it is estimated that the normal proteinuria rate for healthy adults is less than 0.3 g/liter . If an initial urine sample reveals excessive proteinuria, a 24-hour urine collection will confirm and refine the diagnosis. If proteinuria is confirmed, additional tests and monitoring will be undertaken.

Excess protein in the urine is usually asymptomatic. Also, unless urine tests are done regularly, there is no way to know if proteinuria is normal or not. However, during pregnancy, proteinuria can be associated with a health problem that threatens both the fetus and the mother-to-be. It is therefore customary for pregnant women to have a urine test every month to detect possible proteinuria . If the monthly screening from a urine stream sample reveals a high proteinuria level, the pregnant woman will be prescribed a 24-hour test. All of the patient's urine is then collected for a full day and night, from one morning to the next. If the 24-hour test confirms excess protein, the mother-to-be's blood pressure will be tested.

Generally, medical analysis laboratories set the limit at around 150 mg/l, in other words 0.15 g/l , but this is the limit outside pregnancy. In pregnant women, additional analyses (collection and dosage of urine over 24 hours, monitoring of blood pressure) are often prescribed from 0.3 g/l (or 300 mg/l) , but this may depend on the doctor or midwife who is monitoring the pregnancy, and the patient's history. "  Proteinuria is not necessarily worrying at time T ," confirms Tiphanie Larue, " the important thing is to monitor the evolution of the protein level. If proteinuria is not confirmed by analysis within 24 hours, the excess may, for example, be linked to diet.  "

High proteinuria during pregnancy may be linked to a urinary tract infection. To rule out or confirm this diagnosis, a cytobacteriological examination of the urine (ECBU) may be prescribed. Urine tests carried out during pregnancy monitoring also aim to measure glycosuria , i.e. the level of glucose (sugar) in the urine, in order to diagnose possible gestational diabetes .

The major risk associated with excessive proteinuria during pregnancy is preeclampsia , or toxemia of pregnancy . This is a serious complication of pregnancy due to placental dysfunction, characterized by high blood pressure, proteinuria, sudden weight gain with edema, and other associated or unrelated symptoms (flies before the eyes, headaches , abdominal pain, etc.).

Although preeclampsia can theoretically occur at any stage of pregnancy, it is more common in the third trimester, a period when extra vigilance is required in terms of monitoring proteinuria and blood pressure. Because preeclampsia is a risky situation for both the mother-to-be and the baby-to-be. Placental abruption with risk of hemorrhage, cerebral hemorrhage, eclamptic crisis (convulsions with loss of consciousness in a situation of preeclampsia), intrauterine growth retardation ( IUGR ) are among the serious complications of preeclampsia.

To avoid these complications, the treatment depends on the progress of the pregnancy, but the best “treatment” remains the induction of labor , if the term of the pregnancy allows it to be considered.

If preeclampsia occurs too early in pregnancy, antihypertensives, rest, or even hospitalization for close monitoring are suggested.   Before 37 weeks, we will not induce labor for preeclampsia, we will simply stabilize as much as possible. Today, we can hold out like this for 15 days, 3 weeks .