Treatment methods for pregnant women with heart conditions typically involve lifestyle changes or drugs. However, drugs can affect the baby negatively.
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A small number of women, such as those with heart diseases, will need extra monitoring in the course of their pregnancy.
Worldwide, up to 1 per cent of pregnant women may have some form of heart disease. This is either pre-existing or developed in the course of the pregnancy.
Some women are born with congenital heart defects. About 0.8 per cent of all live births have this condition, said senior consultant cardiologist Tan Ju Le from the National Heart Centre Singapore (NHCS).
It can range from a hole in the heart to defective ventricles and can lead to more serious problems such as Eisenmenger's syndrome where heart defects give rise to higher blood pressure in the lungs.
This higher pressure damages fine blood vessels in the lungs, reducing the amount of oxygen that enters the blood to be transported to other organs.
It results in a 'blue mother' with low oxygen levels in the blood for the baby and greatly reduces the chance of a live birth if a woman has this syndrome, said NHCS's Dr Tan.
The risk of the mother dying, especially in the later stages of pregnancy, is about 30 to 40 per cent, she added.
Pre-existing heart conditions can also arise from diseases suffered when the women were younger, such as rheumatic fever, which damages the heart.
However, such cases are now less common among locals and are mainly found in immigrants, said Dr Tan Lay Kok, a senior consultant at the obstetrics and gynaecology department at Singapore General Hospital (SGH).
There are also some mothers who have no history of heart disease but develop a heart problem called peripartum cardiomyopathy in the course of pregnancy.
This condition, which causes the heart muscles to weaken, tends to strike in the last month of pregnancy or in the first five months after delivery. Heart failure can occur.
While the exact cause is still being researched, it only affects a small number of pregnant women.
Other cardiovascular conditions, such as hypertension and diabetes, may hit pregnant mothers too.
Both can occur in women not known to previously have the disease and can adversely affect the baby, causing premature delivery or foetal death.
Hypertension, in particular, can indicate a more serious problem such as preeclampsia, where a spike in the blood pressure and in the protein level in the blood threaten the placenta and the baby's life. The mother may have a seizure.
Preeclampsia, which can occur as early as in the 26th week of pregnancy, largely affects very young or older mothers, first-time mothers, women carrying multiple babies and those with underlying chronic problems like high blood pressure and obesity, said SGH's Dr Tan.
Premature delivery is sometimes the only way to save both the mother and baby's lives - but a premature baby faces many challenges, he said.
Women who have a pre-existing heart problem and are considering having a baby should discuss this with their doctors. This is because their condition can get worse from the increased demands on their heart during pregnancy, said doctors.
Patients with high-risk heart defects may be advised to undergo surgery before considering pregnancy or to put off the decision to bear children, said SGH's Dr Tan.
For those whose condition can be controlled, treatment methods would vary depending on the condition faced by the mother.
Treatment methods typically involve lifestyle changes or drugs. However, drugs are often not an option as some medication can affect the baby, said NHCS's Dr Tan.
A British report in 2007 - The Confidential Enquiry Into Maternal And Child Health - showed that cardiac problems were the leading indirect cause of death in pregnant women living in Britain between 2002 and 2005, accounting for 30 per cent of the indirect maternal deaths there.
Doctors whom Mind Your Body spoke to expect the number of mothers with heart disease to rise.
NHCS's Dr Tan said one reason for this is that more children with congenital heart diseases now survive to adulthood.
Another reason is that more women are postponing childbirth and older women tend to have more problems such as high blood pressure and diabetes, she added.
Mum and baby's fight to survive
Throughout her pregnancy last year, housewife Jenny Lim (not her real name) and her baby battled for their lives.
Madam Lim, 27, has hypertrophic cardiomyopathy, a genetic condition where her heart muscles are thickened, making it harder for blood to be pumped from the heart.
Her father had the same disease.
As a child, she would get breathless, have chest pains and frequent fainting spells, while her classmates could run around freely.
She had to rely on medication to keep her blood pressure down and blood vessels open so that blood could flow freely.
She got married in 2008 and her gynaecologist advised her not to become pregnant. She was told that she could suffer heart failure and that her baby would have a one in two chance of developing heart defects.
A situation might arise in which her husband would have to choose between saving her and their child. 'But we wanted kids,' said Madam Lim, who was overjoyed when she became pregnant last year.
However, with her elation came pregnancy complications. She suffered heart palpitations, breathlessness and giddy spells, which got worse as her pregnancy progressed and she had to be put on bed rest from her second trimester.
She was unable to take medication for her condition because it could have put her baby's development in danger.
At the end of eight months, her condition took a turn for the worst.
Her feet swelled on Christmas eve, a worrying sign for someone with her disease. Her breathlessness became so bad that she had to force herself to yawn constantly so that she could get oxygen.
Her contractions had also started and her cervix was dilated. Doctors wanted to stop the dilation because the baby was still premature.
A scan revealed she had water in her lungs and doctors ordered an emergency Caesarean operation. The baby had to be delivered to save both his and her lives.
Madam Lim's baby boy, prematurely delivered and not breathing, was rushed to neonatal intensive care.
However, things got better from then on and now, more than three months later, mum and baby are back home.
Madam Lim said that her son now cries so loudly the whole neighbourhood can hear him.
He has to be checked by a paediatrician every month and it is still too early to tell if he has inherited any of his mother and grandfather's heart problems.
Madam Lim, who is back on medication for her condition, hopes to have three children eventually. 'I feel very lucky that both of us are alive. Being able to have a kid is a gift to me.'
Other problems
Pre-existing heart diseases aside, Assistant Professor Tan Thiam Chye from KK Women's and Children's Hospital said that these are some of the other health problems that pregnant women may encounter:
Pregnancy-induced hypertension
The actual cause is not known but those at risk include first-time mothers, those above 35 years of age, those with twins or triplets and those with pre-existing hypertension or diabetes.
Gestational diabetes
Diabetes can occur in pregnancy when the body does not produce adequate amounts of the hormone insulin to deal with sugar control.
Frequent urination
Pregnancy increases the amount of fluids in the body and urine production. Later on, the expanding womb also presses on the bladder.
Headaches
This is caused by hormonal changes in the body.
Backaches
The baby's weight puts increased stress on the back.
Constipation
Food moves along more slowly in the intestines, which are compressed by the womb.
Heartburn
This is caused by the slowing down of the digestive tract and the relaxation of the muscles at the opening of the stomach, resulting in the reflux of acidic gastric juice.
Swelling of the legs
This is common as the body retains more fluid and the growing womb adds pressure to the legs, causing them to swell.
Numbness in the hands
This is commonly associated with a condition known as carpal tunnel syndrome, where the median nerve in the hand is compressed by the swelling encountered during pregnancy.
Haemorrhoids or piles
Pregnancy causes blood vessels in the rectal region to become engorged.
Varicose veins
They occur as the expanding womb puts pressure on the blood vessels, causing them to enlarge.
Source: The Straits Times © Singapore Press Holdings Limited. Permission required for reproduction.
