Placenta Previa Causes: Genetic or Other Reasons

Placenta Previa Causes

Placenta previa causes continue to be a highly debated subject. This complication is generally seen in the later stages of pregnancy. It could be a result of many factors. They say no two pregnancies are similar. In the case of a placenta previa too, it is applicable. Placenta previa is a rather severe pregnancy-related complication and may result in severe bleeding coupled with cramps.

Though not very common, the risk continues to be around 0.3-0.5 percent in every pregnancy. There are various causes attributed to its origin. However, some of the risks seem superior to others. These risks could stem from a series of physiological and lifestyle conditions.

The Primary Causes of Placenta Previa

Placenta previa causes may vary from person to person. But some triggers increase the risk of this condition. We can divide these into two key sub-parts.

These sub-parts are created depending on how the placenta previa comes about. We all know that it is an abnormal growth. So, understanding the trigger is of primary importance. Though it can’t help you in curing the condition, you can always take precautions to limit the chances of such a condition. Here is a quick lowdown-

  • Placental Triggers

As the name indicates, this refers to conditions in the placenta that abet the growth of placenta previa. According to most studies, the placenta previa is normally an outcome of an oversized placental length.

The question is, why the placenta would grow longer than required? Often, this is the result of lower functionality. Supposing the placenta cannot deliver oxygen or nutrients at the appropriate level, it grows longer in size to compensate. This leads to a greater chance of the Previa coming to play.

It goes without saying that decreased functionality is an outcome of physiological changes in your body. Smoking, several instances of gestation and high altitude stay can lead to abetment of this.

  • Uterine Triggers

Some factors contribute to the placenta growth as a result of complications in the uterus. Here again, these are the outcome of physiological complications in the uterine region. Scarring in the upper lining tissues of a uterus could be the primary reason for placenta previa in many women.

There are many reasons why scarring might happen. It could be a result of Cesarean deliveries earlier. In fact, any type of surgery in the region could result in this. This includes procedures like D&C in case of miscarriages or even too many abortions. So, if there are too many surgeries in your uterine cavity, this might abet the possibility of Placenta previa.

All in all, though there are distinctive reasons that are considered as placenta previa causes. They can be grouped together in the two sub-heads. The bottom line is damage to either the uterus or the placenta results in this condition. But how do you end up knowing what damages the placenta or uterine cavity?

Major Triggers For Placenta Previa

Well, we decided to analyze some of the most popular beliefs or reasons that cause placenta previa. These are not just grandmother’s tales but also developments supported by a series of medical studies and surveys.

How Does Smoking Trigger Placenta Previa?

If you take a straw poll, nine out of ten people will tell you that smoking during pregnancy can result in placenta previa. But have you wondered why and how?

Well, we explained earlier that if the placenta does not perform at par, there are chances of increasing the surface area. It is the compensation process. But the question is, why does it result in this?

It is a common assumption that continued smoking results in Carbon monoxide hypoxemia. In simple terms, this means that it interferes with the quality and quantity of oxygen supply through the placenta. Obviously, the placenta then gets into the compensatory mode. That results in elongation and an increase in its surface area. Finally, this results in the much-dreaded placenta previa.

This is the reason that people often avoid smoking during pregnancy. This helps in maintaining the quality of air supply to the fetus via the placenta. Series of clinical studies and surveys of pregnant women with placenta previa have corroborated this assumption. So, it can be one of the reasons that trigger this condition.

Late Pregnancy Increases the Risk of Placenta Previa

When you are looking for placenta previa causes, pregnancy in later years could also be a significant factor. This is because, as the woman’s body ages, there could be physiological complications. This impacts both the uterine and placental triggers.

As a result of this, they run the risk of compensatory placental function. For women, who are over 35 years of age, the risk is significantly more pronounced. While there is no specific age bar, clinical studies have revealed distinct possibilities beyond 35 years of age.

On average, most pregnancies beyond age 35 are a risky affair because of many associated complications. There is no optimal timing for motherhood, but suffice it to say that beyond 35, the odds increase. As the risk of other associated conditions increases, the chances of placenta previa increase from 1 in 200 to 1 in 20.  Just that number on its own highlights the risk significantly.

Multiple Pregnancies Increase Risk

We mentioned earlier that procedures in the uterine cavity could trigger placenta previa. So if someone is having twins or has had multiple pregnancies, the risk increases. When you are looking for placenta previa causes, this is definitely one of the key ones.

Every pregnancy translated to additional pressure on the uterus. So, its ability and functionality surely get impacted. As a result, this then triggers the emergency response of the placenta. As a result, it begins elongating and, in some severe cases, completely covers the vaginal opening.

A woman who has had a history of more than 4-5 pregnancies becomes susceptible to this condition. This could also relate to your overall health. In case you are malnourished and had more than four pregnancies, the risk is even more pronounced. At the end of the day, it is all about how much nourishment the fetus is receiving.

Cesarean Delivery Can Trigger Placenta Previa

This is exactly the reason that multiple cesarean deliveries can also lead to placenta previa. C-section entails surgery in the uterus region. This abets the risk of placenta previa.

This is because C-section leads to the scarring of the uterine tissues, which triggers the distinct possibility of developing this condition. Unlike a natural delivery, C-section leads to a series of procedures that can impact the overall uterus. As a result, if you have had more than two C-sections, it is always good to be careful about this condition.

Genetic Triggers for Placenta Previa

Quite interestingly, there are a series of studies to ascertain the role of genetics as a potential placenta previa cause. Though scientists have been able to create some sort of association, it is not very pronounced.

Differently expressed genes surely have an impact in abetting or reducing the chances of placenta previa. But genes as the sole cause is yet to be ascertained. Several complex studies show a variety of genetic elements responsible for increasing or reducing the severity of the Previa.

In some cases, genes have contributed to the Previa taking up a life-threatening proportion with significant bleeding, even resulting in Cesarean hysterectomy.

Therefore, we can assume that genes do have a role to play in the eventual demonstration. Some are more prone to it than others. Genetic correlation with other pregnancy-related complications also has a role in this. In some cases, that might trigger some sudden worsening of the condition.

However, when you compare its genetic correlation with other conditions like postpartum hemorrhage or placental abruption, it is significantly lower.

You must remember that this is a subject on which there are studies underway. As a result, there is no conclusive inference on the correlation yet. So, this is a theory that still needs considerable probing and studying.


Therefore, for just academic purposes, it is suffice to say that there are many possibilities that may result in placenta previa. You must remember that there is no cure for it. Rest and precaution are the only options in case it develops. You should be cautious to limit the risk and cut down the possible triggers for this condition.

The most common placenta previa causes are late pregnancy, smoking habits and history of abortion. So, it is no secret that a healthy lifestyle will surely help if you are planning babies. Most importantly, give up smoking. Quitting smoking helps not only your body, but also your future child.

However, the good news is most women with placenta previa deliver healthy babies. There is nothing much to worry apart from the bleeding severity.

Be the first to comment

Leave a Reply

Your email address will not be published.