Polyhydramnios Flashcards
Define Polyhydramnios
- AFV of 2,000 mL or greater at term
- DVP is greater than or equal to 8 cm
- AFI is above the 95th percentile for the particular gestational age
- AFI is more than or equal 25 cm
Degrees of polyhydramnios are based on
he measurement of the largest vertical pocket of liquor.
What is mild polyhydramnios
Largest vertical pocket of liquor measures 8–11 cm
AFI: 25.0–29.9 cm
What is moderate polyhydramnios
Largest vertical pocket of liquor measures 12–15 cm
AFI: 30–34.9 cm
What is severe polyhydramnios
Largest vertical pocket of liquor measures >16 cm
AFI: >35
What is the incidence of polyhydramnios
0.2-4%
Define the course of amniotic fluid when it starts increasing, reaching plateau and declining
- ** Increases up to: 33 Weeks
- Plateau: 33-38 Weeks
- Declining: 38-42 Weeks**
Factors affect Amniotic fluid balance
amniotic fluid production
* fetal urine production
* secretions from the respiratory tract
* oral secretions
amniotic fluid removal
* fetal swallowing
fluid dynamics across the membranes
* transfer across the placenta, umbilical cord, and fetal skin (intramembranous flow)
* across the fetal membranes (transmembranous flow)
Abnormality of these mechanisms leads to excessive accumulation of AF.
Methods for assessment of amniotic fluid
Ultrasound evaluation of the amount of amniotic fluid:
* deepest vertical pocket (DVP)
or
* amniotic fluid index (AFI)
The AFI is calculated by
obtaining a sum of the vertical dimensions of four quadrants of the uterus without any cord ot limb meausred
Normal: 5-25
DVP is calculated by
(Single deepest pocket) the largest visible pocket of amniotic fluid without any limb or cord measured
Normal: 2-8 cm
Most common cause of polyhydramnios in sigleton pregnancy
Idiopathic 60%
Most common fetal complication of mother uses lithium
Fetal nephrogenic diabetes insipidus
Most common Known cause of polyhydramnios in sigleton pregnancy
Maternal Diabetes
How Maternal DM causes polyhydramnios
Pederson’s Hypothesis:
Maternal Hyperglycemia leads to fetal hyperglycemia and hyper-insulinemia leading to polyuria by osmotic action
Fetal causes of Polyhydramnios
- Congenital malformations
- Chromosomal and genetic abnormalities, e.g. trisomies, Beckwith–Wiedemann syndrome, fetal akinesia–dyskinesia syndrome
- Congenital infections, e.g. toxoplasma, rubella, cytomegalovirus, and parvovirus
- Macrosomia
- Fetal tumours, e.g. teratomas, nephromas, neuroblastoma, and haemangiomas
Maternal Causes of polyhydramnios
- Uncontrolled diabetes mellitus 2. (pregestational and gestational)
- Rhesus and other blood group isoimmunisation leading to immune hydrops
- Drug exposure, e.g. lithium leading to fetal diabetes
Fetal CNS disorders that cause polyhydramnios
- Anencephaly
- Spina bifida
- Encephalocele
- Hydrocephalus
- Microcephaly
- Dandy–Walker malformation
Fetal Respiratory disorders that cause polyhydramnios
- Tracheal agenesis
- Congenital diaphragmatic hernia
- Congenital cystic adenomatoid malformation
- Bronchopulmonary sequestration
Fetal GIT disorders that cause polyhydramnios
- Esophageal atresia
- Tracheo-oesophageal fistula
- Duodenal and intestinal atresia
- Exomphalos
- Gastroschisis
Fetal Genitourinary disorders that cause polyhydramnios
- Pelvi-uretric junction obstruction
- Bartter syndrome
Fetal Head & neck disorders that cause polyhydramnios
Goitre, cystic hygroma, cleft palate
Perinatal mortality & morbidity increase due to polyhydramnios
2-5 folds
Maternal Complications of polyhydramnios
4U 6P 1G
Presentation (abnormal)
PROM
Placental abruption
Premature delivery
PPH
Perinatal mortality
Unstable lie
Uterine inversion
Uterine dysfunction
Umbilical cord prolapse
GDM
Fetal Complications of polyhydramnios
- Congenital malformations
- Increased perinatal morbidity
- Stillbirths
- Preterm births
Polyhydramnios
Inspite of normal sonographic monitoring, risk of major anomaly is
with mild: 1%
with moderate: 2%
with severe: 11%
polyhydramnios
Indication of referral to fetal medicine specialist
- suspected fetal anomaly
- small for gestational age fetus
- concerns with fetal movements
- persistent or worsening polyhydramnios.
Therapuetic ttt we can use to relief symptoms of polyhydramnios
Therapeutic amniocentesis or amniodrainage has been used to treat symptomatic polyhydramnios in order to minimise respiratory embarrassment.
also used in pts w/ significant cx shortening to avoid preterm birth.
In case of mild to moderate unexplaind polyhydramnios, how we monitor this pt. in the rest of her antenatal period
Mild to moderate: Serial growth scan + TVS = for cx lengh
Severe: presistent causing maternal complications refere to FMU
Only discomfort: Therpuetic amniosentesis
Management n case of suspected fetal anomaly (IUGR- SGA- fetal aneuploidy or infections)
refer to FMU directly
Management n case of suspected maternal infections, DM or red cell antibodies in a case of polyhydramnios
refer to FMU directly
What will we do if we find cx shortening due to polyhydramnios
- Considered High risk
- Antnatal corticosteroids for lung maturation
- Hospital with intensive car unit for delivery within 24 hours
What is the risks of preterm labour due to polyhydramnios
* unstable lie requiring delivery by caesarean section
* umbilical cord prolapse
* abruptio placentae
* postpartum haemorrhage.
In which cases of polyhydramnios we need IOL
when polyhydramnios is a part of the clinical picture such as uncontrolled maternal diabetes or associated with other obstetric conditions such as prolonged pregnancy, maternal hypertension, etc.
How we manage polyhydramnios patients in labour
Controlled amniotomy in theatre
Continous fetal monitoring
Anticipation of complications like shoulder dystocia & PPH
What is fetal loss rates related to polyhydramnios
4% increases to 60% with coexistent structural anomaly
Sum up of management after diagnosis of poly hydramnios
- Investigate
- maternal RBS/GTT/ HbA1c/ Toxoplasma/ CMV/ PArvovirus/ Red cell antibodies
- Detailed U/S for fetal anomalies, weight, stomach & movements
- TVS for Cx. lenght
How much of AF do we draw for amnio reduction
It has 2 parameters:
1. AFI become normal less than 25. OR
2. mother gets symptomatic relief
