What is pregnancy induced hypertension (PIH)?
Pregnancy induced hypertension (PIH), also called preeclampsia or toxemia is a severe form of pregnancy high blood pressure. It is defined as high blood pressure that is present 20 weeks after pregnancy and returns to normal 6 weeks after birth. It is associated with excess protein in urine, but PIH can be present without proteinuria.
Who is at risk?
It occurs most often in women who are first time mothers. It is also common in women who have had preeclampsia before, have high body mass index (BMI) prior to pregnancy, black women, multiple pregnancies (women expecting more than one baby per pregnancy), and in women who have underlying medical conditions such as kidney diseases or diabetes mellitus.
How do I know when I have it?
The following are some signs and symptoms:
severe headache
changes in vision (blurry vision, temporary blindness, see double)
upper abdominal pain
nausea and vomiting
decreased passage of urine
excess protein in urine (proteinuria)
low levels of platelets
shortness of breath
swelling (oedema)
The diagnosis can be made by blood pressure measurement, running tests that either confirm or exclude the above signs such as urine tests (24-hour urine test, urine dipsticks), blood tests (liver function test, kidney function test, and full blood count), and eye examination.
A blood pressure measurement of 140/90 or more plus above signs and symptoms is confirmative of PIH.
The doctor may also check the baby’s health by using an ultrasound scan to see whether the baby is growing well and to check the placenta and fluid around the baby to make sure the baby is healthy. The doctor may further check the baby’s heart rate in relation to its movement.
What complications PIH cause in pregnancy?
High blood pressure increases resistance in the blood vessels thus compromising or reducing blood flow to the organs in the body of a pregnant woman such as placenta, kidneys, heart, and the brain. This causes problems for the mother and baby.
Problems to the mother:
Abruptio placentae which is the early detachment of the placenta from the uterus causing heavy vaginal bleeding. The baby may not get adequate oxygen and nutrients. These may be life threatening to the mother and baby.
HELLP syndrome is a severe form of preeclampsia. It is a serious condition that affects the blood and the liver. It is usually present in the third trimester of pregnancy but may occur before and after delivery (first week after delivery). HELLP syndrome is a medical emergency and requires prompt treatment. Failure to treat HELLP syndrome may result in the death of the mother and baby.
Eclampsia is seizures that occur because of high blood pressure during pregnancy.
Pulmonary oedema is fluid build up in the lungs and presents with difficulty breathing.
Low platelets (Thrombocytopenia): Platelets are the components of blood responsible for clotting. Low levels of them increase the risk of bleeding.
Organ failure (kidney or renal failure, heart failure, and liver failure).
Problems to the unborn baby (Fetus):
Placental insufficiency: Placenta is a temporary organ that develops in the uterus during pregnancy. It supplies the baby with oxygen and nutrients, and removes the toxins from the baby. Placental insufficiency is a condition where oxygen and nutrients are not adequately transferred to the baby, due to high blood pressure (in this case).
Placental infarctions are caused by the interruption in blood flow between the placenta and the baby that causes small lesions to occur on the placenta.
Slow growing baby (Intrauterine growth restriction): The baby has poor growth because high blood pressure decreases the blood flow to the placenta thus decreasing the oxygen and nutrients the baby needs. With less blood flowing to the placenta, toxins are also not cleared as much as needed.
Fetal distress is a sign that the baby in the uterus is not well. This occurs because the baby is not receiving enough oxygen.
Stillbirth: The baby is born dead after 24 completed weeks of pregnancy. (The pregnancy duration in the definition may differ from place to place.)
Premature births: A doctor may decide to deliver the baby to prevent further complications. While this may stop the progression of the condition, the baby may be at risk of conditions associated with prematurity such as infections and hypoglycemia.
How is PIH treated?
Treatment of PIH is depended on the severity of the condition and duration of pregnancy. If the condition is mild and pregnancy is under 37 weeks, the doctor may recommend frequent visits so that he can monitor the baby and the mother. If pregnancy is over 37 weeks and both the mother and the baby are stable, the doctor may suggest early delivery.
In severe PIH, the doctor may admit, advice bed red, offer high blood pressure medication that is safe for pregnancy to lower blood pressure, offer medicine that prevents or control seizures (magnesium sulfate), and corticosteroids that help in the development of the baby’s lungs. If, after all this, the PIH is not controlled the doctor may have to deliver the baby.
How to prevent PIH?
Low dose aspirin has been proven to prevent preeclampsia. However, always consult your doctor before taking any medication. Always maintain a healthy lifestyle, both before and during pregnancy, as this may lower the risk of preeclampsia.
This article is written by Dr Katleho Tau (MBChB)
References:
1. March of dimes. Preeclampsia. [Internet]. March of dimes. 2022. Avail from: https://www.marchofdimes.org/complications/preeclampsia.aspx
2. Mayo clinic stuff. Preeclampsia. [Internet]. Mayo clinic. 2022. Avail from: https://www.mayoclinic.org/diseases-conditions/preeclampsia/symptoms-causes/syc-20355745
3. Gaither K. Preeclampsia. [Internet]. WebMD. 2019. Avail from: https://www.webmd.com/baby/preeclampsia-eclampsia
4. Cronje HS, Cilliers JBF, Du Toit MA, Adam Y, Adam S, Bagratee JS, et al. Clinical Obstetrics, a South African perspective. Pretoria. Van schaik Publishers. 2016
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