The Science Of Health: Welcome back to “The Science Of Health“, ABP Live’s weekly health column. Last week, we discussed how the new reference genome, which represents more diversity, will help understand the link between genes and health. This week, we will discuss what preeclampsia is, the risk factors for the condition, and how pregnant women can prevent the disease.
Preeclampsia is a serious medical condition in which a woman, after her 20th week of pregnancy, has high blood pressure, shows signs of liver or kidney damage, has high levels of protein in urine, or exhibits other signs of organ damage.
Preeclampsia: The condition’s incidence and symptoms
Preeclampsia can lead to preterm delivery, or death. The hypertensive condition, if left untreated, can lead to complications for both the mother and baby.
In about two to eight per cent of pregnancy complication cases, women suffer from preeclampsia. The disease accounts for more than 50,000 maternal deaths, and more than 500,000 foetal deaths worldwide, according to the US National Institutes of Health (NIH).
In low-income countries, preeclampsia results in nine to 26 per cent of maternal deaths, and in high-income countries, the disease is responsible for 16 per cent of maternal deaths.
The condition can occur in women who had normal blood pressure before pregnancy.
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In rare cases, preeclampsia can occur in a woman after she delivers her baby. This condition, called postpartum preeclampsia, mostly occurs within 48 hours of delivery.
According to Mayo Clinic, women suffering from preeclampsia should consider early delivery of the baby, the timing depending on the severity of the disease. The pregnant woman is carefully monitored before delivery, and administered with medications to lower her blood pressure.
High blood pressure, the presence of excess protein in the urine, also called proteinuria, and other signs of kidney damage are the defining features of preeclampsia. It is also possible that a woman has preeclampsia, but no noticeable symptoms are there.
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According to Mayo Clinic, common signs and symptoms of preeclampsia, along with high blood pressure and signs of kidney damage are decreased levels of platelets in blood, a condition known as thrombocytopenia; severe headaches; shortness of breath due to the presence of fluid in the lungs; nausea; vomiting; increased liver enzymes; changes in vision, temporary loss of vision, blurred vision, and light sensitivity; and pain in the upper belly, mostly under the ribs, among others.
Sudden weight gain or swelling (edema), particularly in the face and hands, may be signs of preeclampsia. Swelling of the face or areas around the eyes is called periorbital edema.
Sudden weight gain of more than 0.9 kilogram, over one to two days each week may occur in women with preeclampsia, according to the NIH.
Women suffering from severe preeclampsia show symptoms such as headache which does not go away, belly pain on the right side, below the ribs, pain in the right shoulder, nausea and vomiting, lightheadedness, trouble breathing, decreased urination, temporary blindness, and seeing flashing lights, among others.
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What causes preeclampsia, and risk factors for the condition
While the exact cause of preeclampsia is not known, it is believed to start in the placenta, the organ that develops in the uterus during pregnancy, and which provides oxygen and nutrients to the foetus.
When a pregnant woman has preeclampsia, the blood vessels of the placenta do not develop or work properly, and problems with blood circulation in the placenta may result in irregular regulation of blood pressure in the mother, according to Mayo Clinic.
Preeclampsia can occur due to pre-existing autoimmune disorders, a poor diet, blood vessel problems, and genetic factors.
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According to the NIH, the risk factors for preeclampsia include first pregnancy, multiple pregnancy, obesity, having African or American ethnicity, history of thyroid disease, high blood pressure, diabetes and kidney disease, past history of preeclampsia, family history of preeclampsia, and being older than 35 years, among others.
When a woman is pregnant for the first time, she is said to be nulliparous.
Complications in a previous pregnancy, and more than 10 years since previous pregnancy are other risk factors for preeclampsia.
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According to Mayo Clinic, Black women and indigenous women in North America are at greater risk of preeclampsia compared to other women.
Disparities in access to prenatal healthcare, and social, environmental and behavioural factors can also lead to increased risk of preeclampsia.
“The exact cause of preeclampsia is unknown, but there are several identified risk factors. These include nulliparity, maternal age, untreated medical conditions, inter-pregnancy interval, obesity, and hyperthyroidism,” Dr Radhamany K, Clinical Professor & Head, Obstetrics and Gynaecology, Amrita Hospital, Kochi, told ABP Live.
Speaking about maternal age, Dr K explained that being less than 18 years of age, or above 40 increases the risk of developing preeclampsia.
The untreated pre-existing conditions which increase preeclampsia risk include hypertension, diabetes mellitus, hypothyroidism, chronic kidney disease, and autoimmune disorders, according to Dr K.
A prolonged interval of more than 10 years since the last normal pregnancy can increase preeclampsia risk, she said.
“Having an overactive thyroid gland, a condition known as hyperthyroidism, can contribute to an increased risk of preeclampsia,” Dr K added.
How pregnant women can prevent preeclampsia
There is no determined way of preventing preeclampsia, but women with risk factors for the condition can prevent it by taking 81 milligrams of aspirin (baby aspirin) daily towards the end of the first trimester, or early in the second trimester of her pregnancy. Pregnant women must not start consuming baby aspirin without consulting their doctors.
Pregnant women whose calcium intake is low are recommended to consume a calcium supplement daily.
According to Dr K, women who are planning to have a baby must treat pre-existing conditions such as hypertension, diabetes mellitus, hypothyroidism, chronic kidney disease, and autoimmune disorders before conception, to reduce the risk of preeclampsia.
“Women should avoid a prolonged interval of more than 10 years since the last pregnancy. However, if a woman has had preeclampsia in a previous pregnancy, she should avoid a shorter inter-pregnancy interval,” Dr K said.
She explained that if a woman is planning to conceive through assisted reproductive technology (ART), she should consider a single embryo transfer to lower the risk of preeclampsia.
Dr K suggested that women with calcium deficiency should consider taking calcium supplements of 1,000 to 1,500 milligrams on a daily basis.