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Pregnancy Related Complications Explained

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Sahana is pursuing PhD in the field of medical informatics & medical decision support system. She writes on the subject of women's health.


Pregnancy related complications are common experience for women and often requires evaluation. I have discussed here some unique complications that may affect the course of pregnancy, how to recognize them and the available treatment options.

Early complications occur in the first trimester i.e. prior to gestational viability and late complications occur in the third trimester and may impact both the mother and the fetus as the fetus at this stage is typically viable.

1. Miscarriage

Miscarriage means the pregnancy ends on its own usually before 20th week. There can be many reasons for miscarriage, such as genetic abnormalities of the fetus, or an uterine disorder like fibroids. But most of the time the reason for miscarriage remain unknown.

Most chromosomal abnormalities are due damaged egg or sperm cell or due to a problem when zygote goes through the division process.

Some of the other reasons are:

  • Hormonal problems.
  • Smoking or drug abuse.
  • Problem in the implantation of egg in the uterine lining.
  • Mother's age.

According to a study by American College of Obstetrician and Gynecologists (ACOG) about 10% to 15% pregnancies end in miscarriage.

2. Ectopic Pregnancy

An ectopic pregnancy occurs when the egg implants outside the uterus, usually in the fallopian tube. Thus it is also called tubular pregnancy. But sometimes the implantation may also take place in ovary, abdominal space or cervix.

In many cases the pregnancy results in spontaneous miscarriage. However, if ectopic pregnancy continues undiagnosed it can rupture the fallopian tube, giving rise to a life threatening situation.

It is quite difficult to detect an ectopic pregnancy at the initial stage because the woman experiences all the usual symptoms.

Any woman can be at risk of having ectopic pregnancy, but the risk may increase for following reasons:

  • Pelvic inflammatory disease (PID).
  • Endometriosis.
  • Chlamydia.
  • Previous ectopic pregnancy.
  • Several induced abortions.
  • Maternal age greater than 40.
  • Undergoing fertility treatment or using fertility medications.
Ectopic pregnancy caused the fallopian tube to swell

Ectopic pregnancy caused the fallopian tube to swell


  1. Pelvic exam.
  2. USG to determine if the uterus contains any developing fetus.
  3. Measurement of Human Chorionic Gonadotrophin (hCG) hormone level. Lower hCG level may indicate ectopic pregnancy.
  4. Progesterone level check. Low levels of progesterone is an indicator of ectopic pregnancy.
  5. Culdocentesis. It is a procedure that involves inserting a needle into the space at the very top of the vagina, behind the uterus and in front of the rectum. The presence of blood in this area may indicate a ruptured fallopian tube.

Treatment Options


If the ectopic pregnancy is diagnosed before the fallopian tube ruptures, the patient may be given the drug Methotrexate to stop the pregnancy from proceeding. The embryonic tissues will be absorbed by the body.


If the fallopian tube has become stretched or has ruptured immediate surgery is needed to remove the ectopic pregnancy. If the tube is damaged it will have to be repaired or have to be completely removed.

The chances of having a successful pregnancy after an ectopic pregnancy may be reduced, but this will depend on why the pregnancy was ectopic and the medical history. There is a good chance of having a normal pregnancy with one fallopian tube.

3. Chromosomal Abnormalities

Abnormalities in chromosomes or a faulty gene may result in disorder of the fetus. It usually happens as a result of error in cell division.

Meiosis is the cell division egg and sperm undergo when they are developing. It causes each parent to contribute 23 chromosomes. If meiosis doesn't happen normally a baby may have an extra chromosome (trisomy), or have a missing chromosome (monosomy).

Abnormalities can involve the chromosomes themselves or can involve just one or more genes.

Most gene abnormalities do not result in an abnormality in the baby unless an abnormal gene is inherited from both the mother and the father.

Usually, if only one copy of a gene is defective, the 'good copy' from the other parent will take over.

The most common chromosomal abnormality is Down's Syndrome. The other chromosomal abnormalities are extra number 13 chromosome that gives rise to Patau's Syndrome and extra chromosome number 28 which causes Edward's Syndrome. But these two are less common than Down;s Syndrome.

More than 50% miscarriages in the early stage of pregnancy are due to chromosomal abnormalities.

0.5% - 1% of babies are found to have some type of chromosomal abnormality.

Down's Syndrome

Instead of two number 21 chromosomes Down's Syndrome babies have three. Down's syndrome causes a low IQ and distinct features (shown in the image below) such as short limbs and a characteristic wrinkle around the eyes. Heart defects and other problems of internal organs are present at birth.

Risk factor of Down's Syndrome increases with parental age:

  • 1 in 1500 for 20s.
  • 1 in 350 in 30s.
  • 1 in 50 in 40s.

If a mother gave birth to a Down's Syndrome baby then there is a three-fold increased risk of conceiving a baby with Down's Syndrome in any subsequent pregnancy.

Features of a Down's Syndrome baby

Features of a Down's Syndrome baby

A baby girl with Down's Syndrome

A baby girl with Down's Syndrome

Tests to Detect Down's Syndrome

Nuchal Translucency Test

It is an ultrasound test that is carried out between 11 to 14 weeks of pregnancy. It measures the fluid space at the back of the fetus's neck (Nucha means neck). A baby with Down's has more space than a normal one.

By combining this measurement with mother's age and sometimes with hormone measurements in the mother's blood, it is possible to calculate the risk of carrying an affected baby.

Screening tests only asses the risk, they still miss cases. Some women, especially those of advanced age, choose to go directly to amniocentesis or Chorionic Villus Sampling (CVS).


It is a procedure to obtain a small sample of the amniotic fluid that surrounds the baby in the uterus. This is usually carried out at 16 to 18 weeks of pregnancy. Cells shed from the fetus into this fluid are tested for chromosomal or genetic disorders.

But this test carries a small risk of miscarriage.

Chorionic Villus Sampling (CVS)

CVS is performed at 10 to 13 weeks of pregnancy. A sample of chorionic villi is removed from the placenta for testing either through the cervix (transcervical) or through the abdominal wall (transabdominal). The chorionic villi are wispy projections of placental tissue that share the baby's genetic makeup.

CVS can reveal whether a baby has a chromosomal condition, such as Down syndrome.

CVS is considered if:

  1. The mother had positive result in prenatal screening test such as such as the first trimester screen or prenatal cell-free DNA screening.
  2. Chromosomal conditions in previous pregnancy.
  3. Age above 35.
  4. Family history of Down's Syndrome.

Options for Parents

If the tests are abnormal the parents will be offered counselling in order to help them decide whether they want to proceed with the pregnancy or not.

4. Molar Pregnancy

It is a placental abnormality that arises due to a genetic error during fertilization. It's rare and affects 1 in 1000 pregnancies. They are also referred to as Gestational Trophoblastic Disease (GTD).

Types of Molar Pregnancy

Molar pregnancies rarely involve a developing embryo, and the growth of this material is rapid compared to normal fetal growth. It has the appearance of a large and random collection of grape-like cell clusters.

There are two types of molar pregnancies:

  1. Complete molar pregnancy has only the placenta without any baby. Sperm fertilizes an empty egg; hence no fetus forms. Placenta grows and produces the hCG hormone. Thus any home pregnancy test will produce a positive result, but an USG will show the absence of fetus.
  2. Partial molar pregnancy has both the abnormal cells and the embryo which has severe defects. in such cases the fetus is soon overcome by the abnormal mass.

An extremely rare version of partial molar pregnancy is when twins develop, but one embryo develops normally and the other is a 'mole', which is soon absorbed by the healthy embryo.

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Who Can Have Molar Pregnancy

  1. Caucasian women are more at risk.
  2. Women over the age of 40.
  3. Women who had prior molar pregnancy.
  4. Women with history of miscarriage.

If a woman had molar pregnancy there is about 1% - 2% chance of having another molar pregnancy.

USG image of complete molar pregnancy

USG image of complete molar pregnancy

A mole or grape-like structure

A mole or grape-like structure

USG of partial molar pregnancy

USG of partial molar pregnancy

Treatment Options

Most molar pregnancies end spontaneously. Sometimes the mole is removed using Dilation and Curettage (D & C).

Follow-up is done to ensure that the mole has been removed completely. Traces of the mole can begin to grow again and may possess a cancerous-type threat to other parts of the body.

Pregnancy should be avoided for one year after the molar pregnancy.

5. Incompetent Cervix

It is also called Cervical Insufficiency. It occurs usually after the 14th week of pregnancy.

Cervix or neck of the uterus normally stays tightly closed during the pregnancy to keep the fetus in the uterus and opens during the birth. An incompetent cervix starts to open too early; often without any warning the fetus just falls out.

What Causes It

  • Previous cervix surgery or D&C procedure.
  • Damage during difficult birth.
  • Deformed cervix or uterus.

It remains undiagnosed till after second or third trimester miscarriage has occurred. But women with above medical records should be evaluated before or during early pregnancy by USG.

Almost 25% of babies miscarried in the second trimester are due to incompetent cervix.


The treatment is a procedure called Cerclage in which the cervix is sewed. The procedure is usually performed at 14 - 16 weeks of pregnancy. These stitches are removed between 36-38 weeks to prevent any problems when the patient goes into labor. Removal of the cerclage does not result in spontaneous delivery of the baby.

Some possible complications of cerclage are uterine rupture, bladder rupture, cervical laceration etc.

Women who had cerclage should avoid strenuous activity and rest as much as possible for the remainder of the pregnancy.

6. Pre-eclampsia

This potentially serious problem develops at the end of third trimester and may affect 1 in 8 pregnancies. This problem can affect both the mother and the baby.

What Is It?

In mild pre-eclampsia, a pregnant woman develops high blood pressure, together with fluid retention and sometimes protein in the urine.

Severe pre-eclampsia is also accompanied by:

  • head aches.
  • blurred vision.
  • inability to tolerate bright light.
  • fatigue.
  • nausea.
  • passing very little urine.
  • pain in upper right abdomen.
  • shortness of breath.

Treatment Options

If pre-eclampsia is detected while still several weeks of pregnancy to go, the order bed rest, possibly in hospital. In severe case the doctor may advise to have the baby delivered.

Pre-eclamsia usually disappears after delivery.

7. Placental Abruption

This is a common cause of bleeding in late pregnancy. It can be dangerous for both mother and the baby. Though it usually occurs in third trimester, it may occur anytime after the 20th week.

What Is It?

Baby's life support system is the placenta which delivers oxygen and nutrients from the mother to the baby. Normally after the baby is born, the placenta peels off the wall of the uterus and is delivered through the vagina in the final stage of labor.

However, placenta may partially or totally separate from the uterine wall before delivery, causing disruption to the supply of oxygen and nutrients to the baby.

The placenta contains many blood vessels and if it pulls away from the uterine wall before the end of pregnancy, heavy vaginal bleeding can take place. Sometimes there is no visible bleeding, because the blood gets trapped between the placenta and the wall of the uterus. This is called concealed abruption.

The cause is still unknown but high blood pressure, smoking, alcohol intake and drug abuse are some of the contributing factors.

Treatment Options

Treatment varies depending upon the degree of abruption, location of separation and the weeks of pregnancy.

In case of partial abruption, bed rest and close monitoring may be prescribed if the pregnancy has not reached the full maturity. Blood transfusion may be needed in some cases.

In case of total abruption, delivery is the safest course of action.

8. Placenta Previa

This is an abnormal positioning of the placenta that is potentially dangerous for both the mother and the baby.

What Is It?

In early pregnancy the placenta is placed low in the uterus. As the pregnancy progresses, the uterus expands and the placenta re-positions itself near the top of the uterus.

In placenta previa, the placenta remains low in the uterus throughout the pregnancy and may cover part or all of the cervix. This may cause the placenta to separate from the uterine wall as the cervix begins to dilate during labor. As a result, there may be lot of bleeding before or during the delivery.

There are three types of placenta previa:

  • Complete previa : the placenta covers the whole of the cervix.
  • Partial previa: the placenta covers only a part of the cervix.
  • Marginal previa: the placenta is located near the edge of the cervix.

Who Are at Risk?

  • Those who had previous uterine surgery, including c-section.
  • Uterine fibroids.
  • Age above 35.
  • Several previous pregnancies.
  • Multiple babies.

Placenta Previa Vs. Placental Abruption

AssessmentPlacenta PreviaPlacental Abruption



Uterine tenderness; severe abdominal pain and possibly aching or dull pain in the lower back


Bright red

May be concealed; if noted, it is often dark red


No unusual contractions or irritability

Uterine irritability with poor resting tone

Risk for postpartum hemorrhage

High risk; due to low placement of the placenta, there is limited uterine contraction

High risk due to poor contractility of the uterus following an abruption

Different types of placenta previa

Different types of placenta previa

Treatment Options

Placenta previa is usually diagnosed during a routine USG. Patient is then monitored to see if the placenta migrates upward in the uterus as the pregnancy progresses.

Treatment depends on how bad is the bleeding and how far the pregnancy has progressed:

Bed rest : If the patient has light bleeding then she might be advised bed rest and not to take part in any vigorous activity. If the bleeding is heavy, then hospitalization is recommended.

C-Section: If the bleeding is very heavy and does not stop then baby is delivered immediately. Blood transfusion may also be needed.

With placenta previa C-section is the only option of delivery even if there is no bleeding.

9. Placenta Acreta

It is a condition that can be life threatening for both the mother and the baby.

What Is It?

The placenta under normal conditions attaches to the uterine wall. But there is a condition that occurs where placenta attaches itself too deeply into the walls of the uterus. There are three types of attachments:

  • Placenta accreta : The placenta attaches itself too deeply and too firmly into the uterus, but it does not penetrate the uterine muscle.
  • Placenta increta : The placenta attaches even more deeper into the uterus and penetrates the uterine muscle.
  • Placenta percreta : The placenta attaches itself and penetrates through the uterus, sometimes extending to nearby organs, such as the bladder.

Who Are at Risk?

  • Women who had multiple c-sections or had fibroids removed.
  • Smokers.
  • Maternal age over 35.
  • Having placenta previa.


There can be serious complications:

  • Placenta accreta poses a major risk of severe hemorrhage)after delivery. The bleeding be life-threatening as the blood may be prevented from clotting normally. It may as well cause lung failure and kidney failure. A blood transfusion will probably be necessary.
  • Placenta accrete might cause pre mature labor. If placenta accreta causes bleeding during the pregnancy, it might be necessary to deliver your baby early.
Placenta accreta, increta and percreta

Placenta accreta, increta and percreta


  • Placenta accreta may be detected during routine USG. Sometimes MRI is recommended by the physician.
  • Blood test may also be recommended to check for unexplained rise of alpha-fetoprotein — a protein that's produced by the baby and can be detected in the mother's blood. Such a rise has been linked to placenta accreta.

Treatment Options

Nothing can be done to prevent placenta accreta. There is no treatment option available once it is detected. Pregnancy is closely monitored by the doctor to schedule a delivery and to use a surgery that might save the uterus. C-section is done as early as 34 weeks.

A hysterectomy (surgically removing the uterus) is usually done at the same time to prevent severe bleeding.

10. Intrauterine Growth Retardation (IUGR)

IUGR is a condition in which the fetus is smaller than it should be. Delayed growth puts the baby at risk of certain health problems during pregnancy, delivery, and othert health issues such as:

  • Low birth weight.
  • Difficulty handling the stress of the vaginal birth.
  • Low oxygen level.
  • Inability to resist infection.
  • Low blood sugar level.
  • Meconium staining, i.e. swallowing of amniotic fluid stained with fetal stool. This may lead to breathing problem.
  • High red blood cell count.
  • In severe cases IUGR may also lead to still birth.

Who Are at Risk?

  • Maternal weight less than 100 pound.
  • Malnutrition.
  • Use of alcohol, drug and cigarettes.
  • Kidney, lungs or heart disease.
  • Sickle cell anemia.
  • Infections like rubella, syphilis etc.

Types of IUGR

  • Symmetric or primary IUGR : Internal organs are reduced in size. Symmetric IUGR accounts for 20% to 25% of all cases of IUGR.
  • Asymmetric or secondary IUGR : Head and brain are normal in size, but the abdomen is smaller. Typically this is not evident until the third trimester.


The most common way of estimating the size of the baby during pregnancy is by measuring the distance from the maternal fundus i.e. the top of the uterus, to the pubic bone.

After week 20, the measurement corresponds to the number of weeks of pregnancy. A lower than expected measurement may mean the baby is not growing properly.

Treatment Options

  • If the fetus is more than 34 weeks then the doctors usually opt for early delivery.
  • If fetus is less than 34 weeks then monitoring is done till 34th week or beyond. Fetal health and the amount of amniotic fluid are monitored during this time. If any of them become a cause for concern, then delivery is usually recommended. In case the delivery is done prior to 34th week, then amniocentesis is performed to evaluate the maturity of fetal heart.


Pregnancy is a wondrous time in the lives of countless parents. However, this time can be clouded by a variety of complications that affect the mother and the fetus. Fortunately, with early identification and treatment of complications and their side effects, mother and their infants have a greater chance of survival and the potential to thrive after delivery.


Kaushik Goswami on July 14, 2016:

Good one. Informative. Please mention something about Gestational Diabetes.

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