From the Guidelines
Amniotic fluid reduction is primarily indicated for the treatment of polyhydramnios, particularly in cases of twin-twin transfusion syndrome (TTTS) where the maximum vertical pocket (MVP) is greater than 8 cm, as well as for symptomatic polyhydramnios causing maternal respiratory distress or preterm contractions. The goal of amniotic fluid reduction, also known as amnioreduction, is to alleviate symptoms and improve outcomes by reducing intrauterine pressure and improving placental blood flow 1.
Indications for Amniotic Fluid Reduction
- Symptomatic polyhydramnios causing maternal respiratory distress or preterm contractions
- Twin-twin transfusion syndrome (TTTS) with an MVP greater than 8 cm
- Polyhydramnios threatening preterm labor or placental abruption
- Maternal discomfort due to excessive amniotic fluid accumulation
Procedure and Outcomes
The procedure typically involves the removal of 1-3 liters of amniotic fluid under ultrasound guidance using an 18-20 gauge needle 1. The aim is to reduce the MVP to 5-6 cm, which can help alleviate symptoms and improve circulation. However, serial amnioreductions may be necessary as fluid often reaccumulates, particularly in cases of underlying fetal anomalies or diabetes that cause persistent polyhydramnios. According to recent studies, amnioreduction has been associated with average survival rates of 50-65% in cases of TTTS 1.
Considerations and Risks
It is essential to consider the risks and benefits of amnioreduction, including the potential for complications such as preterm premature rupture of the membranes, preterm labor, abruption, infection, and fetal death 1. Consultation with a maternal-fetal medicine specialist is recommended, particularly if the patient is at a gestational age at which laser therapy is potentially an option. Extensive counseling should be provided to patients with pregnancies complicated by TTTS, including the natural history of the disease, management options, and their risks and benefits 1.
From the Research
Indications for Amniotic Fluid Reduction
The indications for amniotic fluid reduction, also known as amnioreduction, are as follows:
- Severe maternal discomfort 2, 3, 4
- Dyspnea (maternal breathing difficulties) 2, 3, 4
- Abdominal and respiratory discomfort 4
- Other issues like satiety 4
Conditions Associated with Polyhydramnios
Polyhydramnios, or the abnormal increase in the volume of amniotic fluid, is associated with various conditions, including:
- Maternal diabetes mellitus 2
- Fetal anomalies, some of which are associated with genetic syndromes 2
- Congenital infection 2
- Alloimmunization 2
- Gastrointestinal malformations 5
- Chromosomal anomaly 5
- Syndromic condition 5
- Neurologic condition 5
Amnioreduction Procedure
The amnioreduction procedure involves draining a large amount of amniotic fluid volume to restore normal amniotic pressure and reduce maternal discomfort 6. The procedure has a complication rate, including spontaneous premature rupture of membranes, abruptio placenta, or chorioamnionitis, regardless of the technique adopted 6. The median volume removed per pregnancy can range from 1500-4260 mL 5, and the median duration from the first amnioreduction until delivery can be around 26 days 5.