Hypertensive disorders in pregnancy

Classifications of Hypertensive disorders in pregnancy

1. Gestational hypertension
2. Pre-eclampsia / Eclampsia
3. Chronic hypertension
4. Superimposed pre-eclampsia


Definitions

1) Gestational hypertension is defined as :

SBP of > 140 mmHg or DBP of > 90 mmHg on 2 occasions 4 hours apart, without proteinuria, Occurs after 20th week of pregnancy or 48-72 hours after delivery.
In a previously normotensive women
Resolves by 12 weeks post-partum.

2) Preclampsia

SBP of > 140 mmHg or DBP of > 90 mmHg on 2 occasions 4 hours apart
With significant proteinuria ( > 300 mg/24 hours, equivalent to 1+ urine dipstick)
Occurs after 20th week of pregnancy
In a previously normotensive women
Resolves by 12 weeks post-partum.


Eclampsia : Tonic clonic seizures with preclampsia


3) Chronic hypertension

Pre-existing chronic hypertension before pregnancy or
Occurs before 20th week of pregnancy or
Persisted beyond 12 weeks post-partum.


4) Superimposed pre-eclampsia

This diagnosis should be reserved only for those with pre-existing chronic hypertension, presented with new onset of significant proteinuria after 20th week of pregnancy.
Superimposed pre-eclampsia should be considered if there is evidence of BP surge or features of severe pre-eclampsia as listed below.

Features of severe preclampsia :

Hypertension (SBP > 160 mmHg or DBP > 110 mmHg, on 2 occasions at least 6 hours apart)
Heavy proteinuria (>5g/24 hours of urine, equivalent to urine dipstick of 3+ or more)
CNS symptoms
Pulmonary edema, cyanosis
Epigastric / RUQ pain
Oliguria (<500 ml/24 hours)
Abnormal liver function
Thrombocytopoenia
Fetal growth restriction

Risk factors for Pre-eclampsia :

1) Maternal age > 35 years old
2) Obesity
3) Primigravida
4) Primipaternity
5) Multiple pregnancy
6) GDM

Complications of Pre-eclampsia :

1) Maternal

Eclampsia
Pre-term delivery
Abruptio Placentae
Post-partum haemorrhage


2) Fetal

Asymmetrical IUGR
Pre-maturity
Oligohydramnios
IUD


Management

The goal of management of pre-eclampsia is to maintain balance between :


1) Reduction/Prevention of Maternal complications of severe pre-eclampsia
2) To prevent neonatal risk of pre-maturity


Treatment for pre-eclampsia, technically is by delivery.

Important points in history taking includes :


1) History of hypertensive or renal disorders in previous pregnancy or before pregnancy
2) When the increased BP and proteinuria occurs
3) Features suggestive of impending eclampsia :


Headache
Nausea/Vomiting
Visual disturbances
Epigastric/RUQ pain
Vaginal bleeding


On examination, pay particular attention towards :


Blood pressure
Weight gain
Edema
Fundal height
Reflexes
Urine dipstick (Urinalysis)


Also the signs of impending eclampsia :

Signs of pulmonary edema
Uterine tenderness
RUQ/Epigastric tenderness
Petechial rashes due to thrombocytopoenia
For those complaining of headache/visual disturbances - fundoscopy

All patients with presumptive diagnosis of pre-eclampsia should be admitted to the hospital, due to :

1) To determine the severity of pre-eclampsia
2) To evaluate presence of any complications in the mother/fetus

Investigations done for the mother :

FBC - platelet count, hematocrit
Lactate dehydrogenase (LDH)
BUSE/Creatinine
Serum uric acid
24 hours urinary protein
Liver function test - ALT, AST, Bilirubin (Total)

Investigations done for the fetus :

Fetal biometry via USG (BPD, HC,AC,FL)
Amount of liquor
Cardiotocography

Now, for those mothers with only mild pre-eclampsia with no fetal distress - conservative management 

These mothers are follow-up closely :

BP, weight gain, S/S of impending eclampsia, urine dipstick, and weekly blood investigations, fetal movement count, fundal height, CTG, USG for fetal biometry and amniotic fluid index.

However, for mothers with severe pre-clampsia - need of admittance in the hospital for the rest of the period of gestation.

POG < 34 weeks - as long as there is no evidence of fetal or maternal compromise, prolongation of gestation is recommended to prevent neonatal risk of pre-maturity
Close monitoring of both mother and fetus.

However, if there is any evidence of clinical deterioration, such as (CARLALU):

CNS symptoms
A
Renal function deterioration
Liver : HELLP syndrome, Coagulopathy
Abnormal fetal testings
Lungs : Pulmonary edema
Uncontrolled BP

To decide on delivery.

Briefly about HELLP syndrome

Seen in about 20% of all cases of severe pre-eclampsia.
Characterized by :

Hemolysis
Elevated Liver Enzyme
Low Platelet Count

High risk of Abruptio Plancetae


POG > 34 weeks - deliver via LSCS or vaginal delivery with cervical ripening using PGE2 followed by amiotomy.

For anti-hypertensive therapy, start as BP is > 140/90 mmHg.

Drug of choice : Methyldopa (250 mg BD - 500 mg QID)
Others : Nifedipine, labetalol, etc

Briefly about Pitchard Regime for Eclampsia :

1) Loading Dose

Slow IV infusion of 4 gm of MgSO4 over a period of 3 minutes
Followed by deep IM injection at both buttocks of 5 gm of MgSO4
Total dose 14 gm

2) Maintenance dose

5 gm MgSO4 IM injection at alternate buttocks 6 hourly, 24 hours after first convulsion or delivery

Therapeutic dose : 4 - 7 gm
Hyporeflexia : 8 - 9 gm
Respiratory depression : 11 - 12 gm
Cardiac arrest : > 14 gm

Category: Obstetrics Notes