Pre-eclampsia is a condition of increased blood pressure associated with other symptoms that are triggered only by pregnancy. It is under the big umbrella of hypertensive disorders during pregnancy which includes gestational diabetes, HELLP (hemolysis, elevated liver enzyme and low platelet) and eclampsia. Pre-eclampsia stands out among the disorders because of how it impacts the mother and baby’s health. The occurring percentage of pre-eclampsia for those who were never pregnant is 3% to 7% and 1% to 3% for those who have multiple pregnancies (Uzan, Carbonnel, Piconne, Asmar, & Ayoubi, 2011).
The World Health Organization is very keen as to the prevention and management of pre-eclampsia because they have a very strong stand on preventing maternal and child morbidity and mortality. Hypertensive disorder among pregnant women have been a significant cause of death and long-term disability among women and their babies. Risk factors of pre-eclampsia includes long term hypertension, obesity, and diabetes, teenage pregnancy, and conditions resulting in large placentas such as in twin pregnancy.
So, what really happens in preeclampsia?
Morphological alterations can already happen during the implantation of the placenta, when spiral arteries of the cytotrophoblast cell of the developing embryo invades the uterus. In a normal pregnancy, when arteries invade the uterus, the muscle fibers in the invading blood vessels (blood vessel walls are smooth muscles) changes in a way that makes it insensitive to substances that cause it to constrict. And we all know that when blood vessels constrict it can lead to increased blood pressure. However, in preeclampsia, this mechanism is already defective. There is this nitric oxide pathway that goes wrong during the implantation and nitric oxide is very important in the control of vascular tone.
In addition to that, maternal formation of nitric oxide prevents implantation of the embryo. When uterine blood vessel resistance takes place, it becomes very sensitive to constriction of the blood vessel thus low oxygenation in the placenta takes place and oxidative stress. Furthermore, this oxidative stress we are talking about releases negative substances into the maternal system such as free radicals, oxidized, lipids, protein substances released by the cells that are important in cell communication (cytokines), and serum soluble vascular endothelial growth factor which are seen to be elevated in preeclampsia. Once these substances are released in the maternal systems it results in the dysfunction of the blood vessel muscles and increases permeability, thrombophilia and hypertension. This process all copes up with the decreased blood flow in the uterine arteries.
Signs and symptoms of Preeclampsia
For mild preeclampsia in addition to high blood pressure, there is retention of excess fluids in the body (which can manifest as edema), and protein in the urine, while severe preeclampsia may have headaches, blurry vision, low tolerance to bright lights, and fatigue.
Management and interventions
So, if we can see, preeclampsia is really a series of events that starts at the beginning of placentation. Delivery is the only treatment for pre-eclampsia and considered an emergency for cesarean section, or in some sources and in extreme cases, termination of pregnancy. However, management of the condition should involve a multiple of disciplines. Participation of the obstetrician, anesthetist, pediatrician, maternal fetal medicine and or nephrologist may be needed. Decisions are focused on balancing maternal risks if pregnancy is continued against the fetal well-being.
Anti-hypertensive medications. These are important only when pre-eclampsia is severe because this is to decrease maternal difficulties and complications such as cerebral hemorrhage or acute pulmonary edema. We have to take note however that aggressive reduction of blood pressure in the mother is actually harmful to the fetus.
Magnesium sulfate. This can be used for severe preeclampsia. It is indicated for the management of convulsions as well as a secondary prevention of eclampsia. However, this medication should have a close monitoring because it can decrease tendon reflexes, and respiratory rate because of its effect on the smooth muscles. Checking of consciousness and urinary output should be done to make sure that there are no toxic levels in the blood streams. If there are signs of over dosage, then the antidote calcium gluconate should be given.
Lung maturation. Clinicians should also make sure that the fetus will achieve lung maturation. So, corticosteroids such as Betamethasone (gold standard of management), together with the gestational age of the fetus will be part of the management.
After delivery, monitoring of blood pressure, adjustment of antihypertensive medications, urination, and weight should be done. In addition to that, neurological assessment which includes assessment for headaches, experiences of seeing bright lights even without the presence of such (phosphene signals), ringing in the ears, and brisk tendon reflexes. Close monitoring is preferably done in the intensive care unit and should be done frequently during the week after delivery.
What about preeclampsia in subsequent pregnancies?
Yes, the condition reappearing in the next pregnancies are always possible. Risk is approximated to be less than 10% for all cases of pre-eclampsia but percentage can be even greater if pre-eclampsia is discovered before the 28th week gestation.
Can preeclampsia be prevented?
Detection of factors that can be modified is very important in the prevention of preeclampsia. Although literature teems with all preventive measures, these need to be interpreted carefully. WHO recommends salt restriction in the diet, calcium and vitamin D supplementation, and antioxidants. Other risk factors that may not be modifiable includes genetic risk factors, family history of pre-eclampsia, immunologic factors and age.
Preeclampsia is indeed a rare pregnancy condition and late detection and management may lead to maternal organ dysfunction and death of the fetus. We may think that carrying the baby for 9 months is our only concern when pregnant, but indeed, pregnancy itself can bring about conditions that cannot be avoided and it is distressing for both the mother and the baby, and even the significant others.
Author: Sarah Catina RN
Uzan, J.; Carbonnel, M.; Piconne, O.; Asmar, R. & Ayoubi, J.M (2011). Pre-eclampsia: pathophysiology, diagnosis, and management. Vasc Health Risk Manag. 7:467-474 doi: 10.2147/VHRM.S20181
World Health Organization (2018). WHO recommendations for prevention and treatment of pre-eclampsia and eclampsia. Retrieved from http://apps.who.int/iris/bitstream/10665/44703/1/9789241548335_eng.pdf