Polyhydramnios

Polyhydramnios

Polyhydramnious is defined as being a quantity of amniotic fluid which exceeds 1500ml. It may not be clinically apparent until it reaches 3000ml. It occurs in 1 in 250 pregnancies.

Causes

·                 Oesophageal atresia of the fetus

·                 Open neural tube defect of the fetus

·                 Multiple pregnancy, especially in the monozygotic twins

·                 Maternal diabetic mellitus

·                 Rarely, Rhesus- isoimmunization

·                 Chorioangioma, a rare tumour of the placenta

Types:

Chronic polyhydramnios is gradual in overt, usually fromabout the 30^th week of pregnancy. It is the most common type. 

Acute polyhydramnios is very rare. It occurs at about 20weeks and comes on very suddenly. The uterus reaches the xiphisternum in about 3 or 4 days. It is frequently associated with monozygotic twins or severe fetal abnormality.

Sign and symptoms

The mother may complain of breathlessness and discomfort If it is acute one, she may have severe abdominal pain

The condition may cause exacerbation of symptoms associated with pregnancy such as indigestion, heart burn and constipation.

Oedema and varicosities of the vulva and lower limbs may be present.

Diagnosis

Abdominal examination

On inspection – the uterus is larger than expected for theperiod of gestation and is globular in shape the skins appears stretched and shiny with marked strike gravidarum and obvious superficial blood vessels.

On palpation- the uterus feels tense and it is difficult to feelthe fetal parts but the fetus may be balloted between the two hands.A fluid thrill may be elicited.

Ascultation auscultation of the fetal heart is difficult becausethe quantity of fluid allows the fetus to move away from the fethoscope.

·                 Ultrasonic scan may be used to confirm the diagnosis and may reveal a multiple pregnancy or fetal abnormality.

Management

The cause of the condition should be determined if possible the mother will usually be admitted to a consultant obstetric unit.

Subsequent care will be depending on:

·                 the mother’s condition

·                 cause of the polyhydramnios

·                 the stage of pregnancy

The general condition of the fetus will be taken in to consideration in choosing the mode and timing of delivery.

The mother should rest in bed. An upright position will help to relive any dyspnoea and she may be given antacids to relive heart burn and nausea.

The mother may need to have labour induced in late pregnancy if the symptoms become worse. The membrane will be ruptured cautiously, allowing the amniotic fluid to drain out slowly in order to avoid altering the lie and to prevent cord prolapse placental abruption is also a hazard if the uterus suddenly diminishes in size.

Complications

Durinig pregnancy

·                 Increased fetal mobility leading to unstable lie and malpresentation

·                 Premature labour

·                 Cord presentation

During labour

·                 cord prolapse

·                 Premature rupture of the membranes

·                 Placental abruption when the membranes rupture

·                 Postpartum hemorrhage