High blood pressure during pregnancy leads to a condition called 'preeclampsia' or 'toxemia' which can result in serious health complications. Magnesium sulfate is used as an anticonvulsant medicine. The objective behind administering magnesium sulfate to a pregnant woman, diagnosed with eclampsia, is to terminate the seizure and prevent maternal and fetal hypoxia (oxygen deficiency). Determining the dosage of magnesium sulfate in pregnancy is crucial; because consumption of excessive magnesium sulfate can lead to life-threatening complications.
Pregnancy Induced Hypertension and Use of Magnesium Sulfate
Accumulated toxins in the body can lead to hypertension and proteinuria in preeclapmsia. Pregnancy induced hypertension or preeclampsia is usually experienced after 20 weeks gestation and can be present as late as 4-6 weeks postpartum. Proteinuria or protein in urine and swelling over the body (edema) is noticed during preeclampsia. This condition can lead to a more serious condition called eclampsia, seizure and/or coma, a life-threatening complication of pregnancy. This can result in placental bleeding, placental abruption and fetal distress.
Magnesium sulfate is used to prevent seizure (a brief loss of awareness) and convulsions (rapid and repeated contraction and relaxation of body muscles) and uterine contractions. Magnesium sulfate helps delay labor in case of premature labor. It is used to delay preterm birth. Intravenous administration of magnesium sulfate helps prevent cerebral palsy in preterm babies. Magnesium sulfate promotes removal of toxins from the body. While administering magnesium sulfate to a pregnant woman, dosage is an important factor. An overdose can result in serious health complications.
Magnesium Sulfate in Pregnancy: Side Effects
Pregnant women (who previously had normal blood pressure) with a blood pressure of 140/90 mm Hg after 20 weeks gestation and proteinuria (≥ 0.3 g protein in 24 hour urine sample) are said to have preeclampsia. These women are administered magnesium sulfate. The side effects of magnesium sulfate include cardiac and central nervous system depression proceeding to respiratory paralysis (ECG changes), hypocalcemia (low calcium levels) with signs of tetany (muscular twitching, cramps and/or seizures), facial flushing, hypotension (abnormally low blood pressure), depressed reflexes, flaccid paralysis, hypothermia (low body temperature), vision problems, chest pain, nasal stuffiness leading to breathing difficulty, circulatory collapse, gastro-intestinal upset, urine retention, magnesium toxicity, tissue necrosis at the injection site, etc.
The newborn infants (whose mothers have been administered magnesium sulfate before delivery) may show symptoms of too much magnesium, for example, neuromuscular or respiratory depression. You may browse 'magnesium sulfate toxicity symptoms' for more information.
Correct dose of magnesium sulfate should be administered to a pregnant woman, diagnosed with preeclampsia or eclampsia. If a pregnant woman has been diagnosed with other disorders like cardiac glycosides/digitalis, kidney problems, etc., magnesium sulfate should be very carefully administered. As magnesium is flushed off through urine, kidney problem can raise magnesium levels in the body, leading to magnesium toxicity. Therefore urine output has to be monitored carefully while administering magnesium sulfate. Magnesium sulfate toxicity is treated with calcium gluconate; which also needs to be delivered very cautiously, as it can lead to 'heart block'. Take a look at the effects of increasing serum magnesium levels in the body.
Increased Magnesium Concentration in the Body
- 0.8 - 1.0 mmol/L: Normal plasma level
- 1.7 - 3.5 mmol/L: Safe therapeutic range
- 2.5 - 5.0 mmol/L: ECG changes
- 4.0 - 5.0 mmol/L: Decreased deep tendon reflexes
- More than 5.0 mmol/L: Absence of deep tendon reflexes
- More than 7.5 mmol/L: Respiratory paralysis and central nervous system depression
- More than 12 mmol/L: Cardiac arrest
I hope the article has succeeded in conveying the message that magnesium sulfate is necessary to prevent the health hazards arising out of preeclampsia or eclampsia in pregnancy. But it should be used during pregnancy only if clearly needed. The dose should be carefully designed and its effects on the body should be sincerely monitored.