Low lying Placenta – why it happens

Help me doctor! That was Sarah’s distress call as soon as she entered the consultation room at our clinic. ‘I have been bleeding since last night: she explained. I urged her to relax so that she could tell me her story clearly. I had noticed that she was pregnant as soon as she entered. Sarah went on to tell me that she was in her second trimester and that was her second pregnancy. Her last menstrual period was on 6 September 2006 and her expected due date was 13 June 2007. She had undergone a Caesarean section during her first pregnancy and the outcome was a healthy baby girl. She had not experienced any problems during the current pregnancy-until the previous night.

She had been attending antenatal clinics since her sixth week of pregnancy. Her antenatal profile was normal; she had also received her tetanus shots.

Sarah told me that this was the first time she had bled in her pregnancy. It had started on 13 February 2007 and she reported to the clinic the following day. The loss of blood was similar to normal periods.

She reported having used three pads but they were not heavily soaked. I asked her whether she had fallen or lost consciousness during this time, to which she said no. She also had no history of being hit on her abdomen. I also enquired whether she was undertaking tasks that required constant bending to which she replied that since she did not have a house help, she did most the housework herself, which inevitably involved bending.

She was working as a project manager for a non-governmental organisation where she was on her feet most of the time. She also travelled a lot due to the nature of her work. The bleeding was painless and no cramps had been experienced. She also said that her baby’s movements were normal. She had not noted any decrease or increase in the baby’s activity.

I proceeded to examine Sarah. She was not pale and her baby’s heartbeat was normal. The pad she was wearing had only a few drops of blood. There was no visible blood loss from her vagina. I explained to her that the most probable reason for her bleeding was a low lying placenta but this would only be confirmed by an ultrasound scan.

Sarah had had no ultrasound scan done yet to check on the progress of her pregnancy. I recommended one, as it would assist in checking for any problems with the baby or the position of her placenta.

After the scan, the doctor’s report confirmed that indeed she had a low-lying placenta Type Three, meaning that the lower edge of the placenta was partially covering the opening of her cervix. (Low lying placentas, also known as placenta previa, are of four types).

It was recommended that she takes one week off-duty and exercised total bed rest. I counselled her to get some help for her household chores. She was also still sexually active so I advised her to abstain from sex as it could worsen the bleeding.

She was released and I gave her a close return date so that we could monitor her case.

On 25 February 2007, Sarah was brought back to the clinic by her husband; she had experienced heavier bleeding. This time she was admitted in the maternity wing for closer observation.

Sarah stayed in hospital for two weeks. The bleeding was controlled by the fifth day after admission but she still spent an extra week in the hospital so that we could monitor her baby’s progress. She was discharged with clear instructions to have further bed rest.

The obstetrician recommended a planned C-section at 38 weeks. He also recommended steroid injections to help her baby’s lungs mature. She was readmitted for the planned C- section which was done on 31 May 2007.

Three months later Sarah came back to our clinic with her baby boy. He was healthy and growing without any problems. Sarah reported that she had been put on iron supplements by her doctor, as she got a bit pale after the operation.

I further advised her on a diet rich in iron, with lots of vegetables, beans and liver to increase her iron levels. She thanked us for the timely assistance she got with her placenta previa.

The placenta is the organ which feeds the baby by giving it oxygen and nutritional support. A normal placenta should be on the upper segment of the uterus. It should be delivered after the baby and that is why it is called ‘The After Birth’.

Dr David Kiragu examines the case of a low-lying placenta, also known as placenta previa.

What is a Low lying placenta 

A low-lying placenta or placenta previa is one that has implanted on the lower segment of the uterus. Ordinarily, the placenta is attached on the upper part of the body of the uterus. When it is implanted on the lower part of the body of the uterus, it is referred to as placenta previa.

How can one tell that she has placenta previa?
In a number of cases one may not know that they have a low-lying placenta as it can happen without exhibiting any symptoms. However, it is one of the causes of bleeding during pregnancy.

How is a low-lying placenta diagnosed?
During the antenatal period, placenta previa can be detected through a routine ultrasound scan, as part of the investigations for causes of vaginal bleeding. The presence of placenta previa can also be confirmed through an internal vaginal examination under anaesthesia, where the physician will feel the placenta on the lower part of the uterus.

Types of low-lying placenta
Low-lying placentas are graded according to their proximity to the cervix (where the baby is going to make its way out). Type four placenta previa completely obstructs the cervix. Type three partially blocks the cervix. Type two is usually at the edges of the cervix and type one is away from the cervical margins. With type one and a few of the type twos, a woman can actually have a normal invariably call for a Caesarean section.

Is there a cause for a low-lying placenta?
There is really no obvious cause. However, some factors increase the probability of its incidence. The two main factors are a previous Caesarean delivery and Dilatation and Curettage (a cleanup of the uterus), which is often performed for management of abortion. The cleaning can also have been done as a diagnostic procedure of abnormal uterine bleeding or for women who have previously gone through manual removal of the placenta after delivery.

Can overworking and bending increase the risk?
These factors would not increase the risk of low-lying placenta; they can however increase the risk of bleeding or increased bleeding from placenta previa.

Is there treatment for a low-lying placenta?
There is no drug that can make the placenta shift. The medication in normal use is blood additives because the mother is losing blood. The other drug that can be relevant is an injection to accelerate the maturation of the baby’s lungs.

It is important to know that many placentas are low during the early trimesters of pregnancy, but as the uterus grows and expands upwards many cases of low-lying placentas will tend to migrate upwards with the expanding uterus so that in relative terms what is initially a low-lying placenta becomes a relatively normal placenta.

For this reason if a doctor recognizes a low-lying placenta in the early stages of pregnancy, there is no cause for panic because, it can ‘migrate’ upwards as the pregnancy advances.

What kind of delivery will a mother with low-lying placenta have?
Bleeding can occur in the antenatal period or it can occur during the delivery. If bleeding does not occur during pregnancy, for ‘major types’ of placenta previa, the potential problem will be severe bleeding during delivery.

For placentas that remain very low through the late stages of pregnancy, delivery of the baby by C-section is recommended in order to avert severe bleeding during delivery.

Bleeding during delivery is bad for the well being of the mother and the baby, and can be fatal. The timing of the C-section would depend on two considerations: one, the maturity of the baby; and two, the severity of the bleeding.

If the bleeding does not significantly compromise the well being of the baby or the mother then the two are monitored closely and delivery achieved at full maturity of the baby, which is 38 weeks.

However if in a doctor’s view the mother is bleeding too much, the only way out is to undertake a premature C-section delivery. In such instances, a doctor will accelerate the maturity of the baby’s lungs using a steroid injection prior to the delivery.

A low-lying placenta will not kill the baby per se. It is the bleeding which can cause intrauterine death, leading to a still birth. Severe anaemia, a consequence of bleeding, can have severe implications on the health of the mother as well.

Dr David Kiragu is a consultant Gynaecologist/Obstetrician  based at KAM Health Services, IPS Building, Nairobi.

END: PG 9 /12- 13