Hypertension in Pregnancy: Pregnancy Induced Hypertension (PIH) Causes and Treatment

Hypertension in Pregnancy (High Blood Pressure in Pregnancy)

Hypertension in Pregnancy is also called Gestational Hypertension or Pregnancy Induced Hypertension (PIH). High blood pressure in Pregnancy of 140/90 mmHg measured on two occasions more than 4 hours apart is referred to as Hypertension in Pregnancy; when this elevated blood pressure occurs after 20 weeks, it is referred to as PIH (Pregnancy Induced Hypertension). The reported overall incidence of high BP in pregnancy varies widely, but usually lies between 12 and 25% of all pregnancies.

Hypertension in Pregnancy could `also be defined as a blood pressure rise of more than 30mmHg in systolic blood pressure over the booking blood pressure. This means that if the booking blood pressure of a pregnant woman is 100/60mmHgand later in pregnancy she develops a blood pressure of 135/60mmHg – she is said to still have Hypertension in pregnancy because there is a rise of more than 30mmHg in the systolic blood pressure.

Hypertension in pregnancy can again be defined as a rise of more than 15mmHg in diastolic blood pressure over the booking figure. This means when a pregnant woman has a booking blood pressure of 120/80mmHg and later on develops a blood pressure of 120/100mmHg, she still has hypertension in Pregnancy because there is a rise of more than 15mmHg in the diastolic blood pressure.

From the above definitions of hypertension in Pregnancy (or Gestational hypertension), one could note that both levels and the rise in the systolic and diastolic are equally important in the diagnosis of hypertension in pregnancy. You dont just look at the systolic blood pressure alone neither would you look only at the diastolic but both. The rise in both the systolic and diastolic blood pressures are equally important. Since we have known the Meaning of Hypertension in Pregnancy, when then will we refer to Hypertension as being induced Pregnancy?

Normal Blood Pressure in Pregnancy (Normal Range of BP in Pregnancy)

The normal resting blood pressure during Pregnancy is virtually never above 120/80 mmHg this is the average normal BP in pregnancy.

What is Pregnancy Induced Hypertension (PIH)

Pregnancy-induced hypertension (PIH) is defined as hypertension occurring for the first time after 20 weeks gestation and in which the blood pressure returns to normal levels within 6 weeks of delivery. Any high blood pressure that is noticed in a pregnant woman for the first time when the pregnancy has passed 20 weeks of gestation is said to have been induced or caused by that pregnancy. This means the woman never had high blood pressure before the pregnancy but as a result of the pregnancy, she now has high blood pressure. PIH normally reverts to normal values by 6 weeks postpartum.

PIH is different from Preeclampsia whereby the hypertension is associated with significant Proteinuria with or without edema. When there is Hypertension, Proteinuria and Convulsion in Pregnancy it is called Eclampsia. All these disorders: Pregnancy induced hypertension (PIH), Preeclampsia and Eclampsia are called Hypertensive disorders in Pregnancy.

What causes high blood pressure in Pregnancy? (PIH Risk factors)

  1. Primigravida (Women that are pregnant for the first time)
  2. Molar pregnancy
  3. Previous history of PIH or Preeclampsia
  4. Multiple gestation (Having twin or more pregnancy)
  5. Diabetes mellitus
  6. Chronic renal failure
  7. New male factor
  8. Hydrops fetalis
  9. Black race

Symptoms of High Blood Pressure in Pregnancy

  1. Headache especially frontal headache
  2. Epigastric pain (Chest pain)
  3. Dizziness and lightheadedness
  4. Seeing flashes of light in the eyes
  5. Right Hyponchondrial pain (Pain over the right lower rib over the liver)

Signs of High Blood Pressure in Pregnancy

  1. Swelling of the legs, hands and face (Edema)
  2. Palpitations (Feeling of the heartbeat)
  3. Sudden weight gain occurring within a short time
  4. Occurrence of significant protein in urine

Pregnancy Induced Hypertension Laboratory Tests (PIH Labs)

  1. Urinalysis to test for protein in urine
  2. Urea, Electrolytes and Creatinine levels (EUCr) with Uric acid levels
  3. Full blood count (FBC)
  4. Liver Function Tests (LFTs)

Pregnancy Induced Hypertension Treatment

  1. Admit patient: this is indicated if the diastolic blood pressure remains at 100 mmHg or more. The presence of proteinuria and evidence of fetal compromise are also indications for admission.
  2. Control Hypertension: this should be done with caution as over reducing the blood pressure reduces placental perfusion. Blood pressure is reduced when mother’s diastolic blood pressure remains persistently above 100 mmHg. Drugs commonly used are Methyldopa, Labetalol and Nifedipine.
  3. Delivery is the ultimate treatment of hypertensive pregnancy and its timing depends on the observations of fetal and maternal well-being noted above. Prolongation of the pregnancy by drug therapy may reduce the risks of prematurity and improve the chances of vaginal delivery.

Pregnancy Induced Hypertension Complications

  1. Intra-uterine growth restriction (IUGR) the risk is increased in cases with proteinuria (i.e in preeclampsia and Eclampsia)
  2. Fetal hypoxia and intra-uterine fetal death
  3. Abruption of the placenta
  4. HELLP syndrome
  5. Eclampsia
  6. Renal failure
  7. Cerebro-vascular accident
  8. Cardiac failure

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