Generality
The low placenta is the insertion of the placental membrane in the lower part of the uterus, in correspondence of the cervix.
This condition is frequently found in the morphological ultrasound of the first trimester . As the gestation progresses and the fetus grows, the low placenta tends to be "dragged" upwards, thus freeing the birth canal. For this reason, only in a small percentage of future mothers (about 10%) with a low placenta in the early stages of pregnancy will they present a placenta previa .
Did you know that…
After the 28th week of gestation, the low placenta is called placenta previa . In the previous period, it is more correct to speak of " low placental insertion ".
Low placenta should be monitored with ultrasound checks, scheduled on a regular basis. The treatment foresees the adoption of suitable measures to allow the normal continuation of the pregnancy (rest, abstention from sexual relations etc.). If complications occur, timely medical intervention is important, such as blood transfusion or caesarean section .
What's this
The placenta is the organ that connects the fetus to the maternal circle. This represents, therefore, the source of oxygen and nourishment for the growing child.
In some women, the placenta fits too low and covers part or all of the cervix. In most cases, the low placenta dates back to the increase in uterine volume and fetal growth, therefore it does not cause problems. Other times, despite the evolution of pregnancy, the placenta continues to remain in the lower part of the uterus, defining a disease known as " placenta previa ".
To remember
The low placenta is an anomaly that it does not have to worry about, since it is diagnosed in time and does not affect the good progress of the gestation . The future mother must adopt, however, some more precautions and, in most cases, the birth of the child takes place with a cesarean.
What happens normally?
To better understand what happens in the low placenta, we need to briefly mention the anatomy of PLACENTA and its role:
- What it is and what functions it performs . The placenta is a "temporary" organ that forms inside the uterus when a pregnancy is established. Its function is to protect and support the growth of the fetus.
- Where it develops . The placenta can grow in any position within the uterus. Depending on the location in which the embryo was implanted, its location may be anterior, posterior, fundic or lateral. In general, the placenta is inserted on the bottom or on the side walls of the organ, at a sufficient distance from the uterine orifice. In other words, the development of the membrane tends not to affect the area adjacent to the birth canal (which occurs, instead, in the low placenta). However, it may happen that the insertion of the placenta occurs abnormally in the lower part of the uterus, too close to the cervix or even above it, partially or totally obstructing access to the birth canal.
What is Placenta Bassa?
Low placenta is an occurrence that occurs when the placental sac engages in the lower part of the uterus, at the cervix. This situation should not be of particular concern in the first months of pregnancy. The low placenta can in fact resolve with the growth of the fetus and the progress of gestation: increasing in volume, the uterus will tend to push the membrane upwards.
Otherwise, that is if the low placenta does not rise, a placenta previa may occur. This condition is potentially dangerous, both for the mother and for the fetus. The placenta previa often prevents the development of natural childbirth, especially if totally occlusive, forcing the expectant mother to make accurate checks and, in most cases, to resort to a cesarean section.
Low placenta is a major cause of vaginal bleeding in the early stages of pregnancy.
Placenta previa: short note
Not all previous placentas are presented in the same way: in some cases, the opening between the uterus and vagina is covered (more serious eventuality); in other cases, the placenta is placed only next to the opening. If the placenta completely covers the cervix, it is called "placenta previa major".
Causes
The low placenta occurs when, immediately after conception, the embryo nestles in a point of the lower segment of the maternal uterus: this event is unpredictable and does not recognize a single specific cause. However, several factors have been identified that can increase the likelihood of this misplaced placenta occurring, especially when they are concomitant with each other.
In particular, situations that may favor the low placenta include:
- Number of previous pregnancies;
- Advanced maternal age (over 35-40 years);
- Abnormal shape of the uterus;
- Previous surgery on the uterus (cesarean section, uterine scrapings, etc.);
- Previous placenta previa episodes (note: the risk of recurrence varies from 4 to 8%);
- Multiple pregnancy;
- Presence of fibroids;
- endometritis;
- Past spontaneous or induced abortions;
- Cigarette smoking and drug abuse.
Symptoms and Complications
Apart from ultrasound evidence, the only symptom that can be spy on the low placenta is an abnormal vaginal bleeding.
In addition to blood loss, other episodic disorders may occur. In some women with low placenta, uterine contractions can occur in particular.
As the uterus becomes larger, the placenta also tends to migrate upwards: if, in the early stages of pregnancy, the incidence of the condition can be estimated at around 20%, in the third quarter this percentage is reduced to to get to 1%.
Low placenta: bleeding characteristics
In pregnant women with a low placenta, blood loss can be considered the only symptom to occur. Vaginal bleeding occurs in the first stage of pregnancy, usually before the 20th week. The blood is bright red.
The onset of blood loss is sudden and, in some cases, intermittent (ie it stops for a few days before resuming). Vaginal bleeding occurs almost always without any pain (unlike what happens, for example, in the case of placental detachment). The quantities of blood lost are variable (sometimes scarce, sometimes abundant).
Risks and disorders associated with the low placenta
- The low placenta in the advanced stages of gestation could prevent the fetus from assuming the normal cephalic position . At the end of pregnancy, therefore, the child could have a breech or transverse presentation .
- If after the 28th week of gestation, the placenta is still low, then it is called placenta previa . This latter condition may be responsible for vaginal bleeding due to the distension of the inferior uterine segment, which favors a detachment (detachment) of the placenta insertion area.
- When the blood loss is accompanied by pain, the specialist doctor will have to quickly make a differential diagnosis with the retro-placental hematoma, placental abruption and the threat of premature birth ; conditions all important for their severity, sometimes associated with placenta previa. In these cases, there is usually no alternative to preterm birth, as the mother's health could face serious risks.
- Some cases of low placenta can be complicated by a pathological adhesion of the membrane to the walls of the uterus (depending on the position, it is defined as accrete, percreta or increta). In this case, at the time of birth, the separation between the two tissues can be difficult and can lead to more serious complications.
Diagnosis
Suspicion of a low placenta often emerges during morphological ultrasonography performed in the first trimester of pregnancy (about 20 weeks after conception). During the examination, the cases in which the placental membrane has a low insertion are identified, therefore there is the risk that in the future it may evolve in the placenta previa.
With the ultrasound examination it is also possible to study the morphology of the placenta and its relations with the uterus, both in terms of extension and location, as well as highlighting the parameters related to the health of the fetus.
For the confirmation or exclusion of this condition a transvaginal ultrasound scan may also be indicated, in which the probe is introduced into the vagina and brought closer to the uterine neck. During the gynecological examination, internal inspection is avoided, so as not to cause uterine stimulation.
Around the 28th-30th week, that is, in correspondence with the gestational epoch in which it can be ascertained whether the placenta has remained before or if it has risen, echography is repeated.
If the placenta is still low in the third trimester of pregnancy, an additional ultrasound scan is recommended to the pregnant woman to verify the position the membrane has taken in relation to uterus distension and fetal growth. As a general guide to the 35th-36th week, therefore, the modality with which to carry out the birth is established with the reference gynecologist.
Treatment
The abnormal positioning of the placenta does not entail a risk situation for the fetus, which can proceed in a completely normal manner in its development. For the child, the danger is constituted by the concrete possibility of having to intervene urgently with a preterm cesarean section, in the event that a placental detachment occurs. Towards the end of pregnancy, in fact, the lower part of the uterus is subject to slight contractions, which could cause even very abundant bleeding or placental rupture .
For this reason, once the gynecologist has confirmed the diagnosis of low placenta, the pregnant woman is monitored closely. The general tendency is to try to carry on the pregnancy naturally, reaching the end of the weeks of gestation. In the meantime, they are recommended: rest, abstention from sexual relations and reduction of physical activity.
Except in cases in which an important bleeding occurs or there are other additional indications, therefore, the delivery can be carried out through caesarean section or traditional modality, around the 37th-38th week of gestation.
When the symptoms indicate a state of imminent danger to the pregnant woman or to the child, instead, the delivery is carried out by emergency cesarean section.
Prenatal measures
If the pregnancy has not yet reached the 34th week, the blood loss is absent or contained and there is no fetal distress, the doctor may decide to wait. Alternatively, he can propose hospitalization to keep mom and baby under control, through frequent monitoring.
If the placenta covers the cervix (placenta previa major) or a suspicion of placenta accreta exists, after the 34 weeks of gestation, hospitalization could be proposed to the patient. Even in the absence of symptoms, in fact, there is a risk of sudden and severe bleeding, which could lead to the need for an urgent cesarean section.
In case of bleeding during pregnancy
Low placenta may predispose to vaginal bleeding during pregnancy. Rarely, blood loss is so important that it requires hemotransfusion or delivery before term.
Cesarean section is considered only if the bleeding is so severe that it poses risks for the woman and the child. In some cases, if the bleeding continues, a hysterectomy (removal of the uterus) may be necessary.
Low placenta: mode of birth
In the case of low placenta, the most adequate delivery method is recommended based on the specific conditions. If the ultrasound at 34 weeks of pregnancy, the margin of the placenta is less than a couple of centimeters from the cervix, it will probably be necessary to use a caesarean section, to avoid suffering the fetus. In many cases, however, the ultrasound check is performed again at the 36th week of gestation, to check if the placenta has "moved", allowing a vaginal delivery .
Important!
Only in the case in which the low placenta is of a marginal or lateral type and the fetus in cephalic presentation, after adequate information on the risks, can vaginal delivery be considered. This must be done, however, in a prepared environment ready for the maternal and neonatal emergency.
Some advice
When the low placenta is diagnosed, some precautions should be followed. First of all, absolute rest is recommended to the pregnant woman, even at home, excluding any type of fatigue.
In case of low placenta, then, it is useful to take the following precautions:
- Undergo medical checks, as programmed by the reference gynecologist;
- Refrain from sexual intercourse, especially if vaginal bleeding has already occurred, as it can stimulate contractions of the cervix;
- Follow a balanced diet, which includes the intake of iron-rich foods, to reduce the risk of anemia;
- Lead a quieter and more rested life, avoiding excessive physical effort;
- Avoid strenuous journeys and do not drive too long; on vacation, it is better to choose locations not too far from health facilities that are suitable for managing any unforeseen events;
- Always carry your blood type and Rh factor card.
If there are vaginal bleeding or bleeding, go to the hospital immediately or alert 118. In emergency situations, in fact, a blood transfusion can be essential to save the life of the future mother and the child.
