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Placenta previa
Last reviewed: 08.07.2025

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Placenta previa is a certain complication during pregnancy.
The placenta is a round, smooth organ that forms during pregnancy to provide the fetus with nutrients and oxygen. It forms immediately after fertilization of the egg on the inner wall of the uterus and, in a normal pregnancy, is quite far from the cervix. But sometimes it happens that it partially or completely covers the cervix. In this case, the diagnosis is placenta previa.
What causes placenta previa and how to reduce the risk of developing this pathology?
The causes of placenta previa have not yet been established, but experts agree that prevention of this pathology includes reducing risk factors, although some of them cannot be controlled.
Controllable risk factors:
- smoking during pregnancy;
- cocaine use.
Uncontrollable risk factors:
- previous operations on the uterus that could change the shape of the uterus - curettage of the uterine cavity, myomectomy;
- C-section;
- 5 or more pregnancies;
- age after 35 years;
- placenta previa during pregnancy in the past.
If the attending physician detects placenta previa before 20 weeks of pregnancy, it is likely that the situation will improve before delivery: in 9 out of 10 cases of placenta previa that are diagnosed before 20 weeks, the pregnancy ends normally. This is explained by the fact that the uterus grows, and, consequently, the position of the placenta changes.
Symptoms of placenta previa
With placenta previa, one or more of the following symptoms may be present:
- sudden, painless vaginal bleeding that ranges from light to heavy and is brightly colored; bleeding can occur up to 20 weeks of pregnancy, but also often occurs in the third trimester;
- Symptoms of preterm labor: One in five women with placenta previa experience uterine contractions.
Bleeding due to placenta previa may stop for a while, but almost always resumes after a few days or weeks. Sometimes this pathology does not cause any symptoms, and this pathology is diagnosed only during an ultrasound examination.
Call an ambulance or go to the nearest emergency room if:
- moderate or heavy bleeding in the first trimester of pregnancy;
- vaginal bleeding in the second or third trimester of pregnancy.
Complications of placenta previa
Placenta previa can cause a number of problems:
- premature detachment of the placenta;
- heavy vaginal bleeding before or during labor;
- placenta accreta;
- If the bleeding cannot be stopped, it may be necessary to remove the uterus;
- the need to extract a premature baby;
- congenital anomalies of the fetus.
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Diagnosis of placenta previa
Ultrasound is used to diagnose placenta previa (partial or complete blockage of the cervix), but the location of the placenta itself is not always determined. A vaginal examination is only performed if a cesarean section is planned, since the intervention can cause severe bleeding and worsen the condition of the woman and put the fetus at risk. Fetal heart rate monitoring is usually done to immediately detect distress. If a decision is made to extract the fetus early, amniocentesis (puncture of the amniotic sac) is performed to determine the condition of the lungs and their ability to function independently. During this procedure, a sample of amniotic fluid is taken from the amniotic sac and a laboratory analysis is performed, the results of which indicate the degree of maturity of the baby's lungs.
Treatment of placenta previa
Treatment for placenta previa depends on:
- severity of bleeding;
- the impact of the problem on the general condition of the woman and the child;
- pregnancy period.
If there is no bleeding, it is important to refrain from sexual intercourse, and if bleeding occurs, immediately go to the doctor, who will conduct a thorough gynecological examination. If bleeding occurs, the pregnant woman is hospitalized. If, with severe bleeding, there is a threat to the life of the woman or the child, who can be considered full-term, the doctor decides to immediately extract the fetus by cesarean section, since there is a risk of deterioration in the condition during vaginal birth.
If placenta previa is diagnosed, treatment depends on:
- the severity of the bleeding (it is important whether the woman is at home or in hospital), the need for a blood transfusion and early removal of the fetus;
- general condition of the pregnant woman (development of anemia as a result of large blood loss);
- the maturity of the fetus and its physical condition (if possible, the extraction of the fetus is postponed until the lungs are able to function on their own);
- the degree of blockage of the cervix by the placenta (usually a cesarean section is performed, since during vaginal birth there may be increased bleeding and a worsening of the woman’s condition).
If placenta previa is diagnosed and there is no bleeding, the woman should follow the recommendations:
- avoid physical activity (do not lift weights or run);
- go to the doctor at the first sign of bleeding, and remind him once again about placenta previa;
- have a phone on hand in case of emergency;
- if examination is necessary, warn doctors about placenta previa and refuse to undergo a vaginal examination;
- abstain from sexual intercourse after the 28th week of pregnancy, and before the 28th week, consult a doctor about the possibility of risk;
- do not use tampons or do vaginal douching;
- be close to the maternity hospital in case there is a need to provide urgent medical care to the woman herself or the premature baby.
If placenta previa is diagnosed and bleeding begins, you need to go to the hospital, where proper care will be provided and all emergency measures will be taken. If the baby is full-term, a cesarean section is performed, but it can be postponed for some time when the bleeding decreases or stops. The possibility of observation depends on many factors:
- If the pregnancy period is 24-34 weeks: 1) corticosteroids are prescribed to accelerate the maturation of the fetal lungs and prepare for premature birth; 2) amyocentesis is performed (analysis of amniotic fluid, which shows the degree of maturity of the fetal lungs); 3) iron-containing drugs are prescribed to prevent anemia; 4) food rich in fiber is recommended, as well as mild laxatives to avoid any straining while using the toilet; 5) if the Rh factor is negative, an Rh antibody vaccination is given, since the fetus may have a positive Rh factor, and when the blood is mixed, the woman's immune system may begin to reject the fetus;
- If bleeding does not stop, be prepared for hospitalization and constant monitoring until the fetus is fully mature; in case of moderate blood loss, a blood transfusion is performed;
- when uterine contractions are observed, tocolytic drugs are administered to reduce labor activity;
- If it happens that stopping the bleeding is not possible, an emergency caesarean section and blood transfusion are performed (the only possible way out of the situation).
Childbirth
In case of placenta previa, a cesarean section is performed. According to statistics, in 25 out of 100 cases of placenta previa, the child is born prematurely (before the 37th week of pregnancy). The child's condition in this case depends on the degree of its maturity. If the child is born prematurely, it stays in intensive care for some time (from several days to several weeks) depending on the severity of the condition. The child is monitored by a neonatologist or perinatologist.
Treatment at home
Vaginal bleeding is possible during pregnancy. Sudden, painless bleeding may be the only symptom of placenta previa, which is a condition in which the placenta partially or completely blocks the cervix. Call 911 immediately if you have heavy vaginal bleeding - blood clots and need to change your pad every two hours (tampons should not be used). Call your doctor or go to the nearest emergency room at the first sign of vaginal bleeding.
Story
If you had placenta previa during your last pregnancy, you may have many questions about your next pregnancy. Depending on the woman's health, your doctor will answer all your questions. In rare cases, this condition can result in a stillborn baby. If this happens, give yourself time to grieve and mourn the loss. Be prepared for your spouse, children, and family members to grieve as well. Attend support groups, talk to other women who have experienced similar grief, talk to family members, or a psychologist.