By Cristina Mestre Ferrer BSc, MSc (embryologist).
Last Update: 04/15/2014

The amniotic fluid is a fluid that surrounds the foetus during pregnancy. Its basic function is to protect the foetus by cushioning the maternal movements. It also helps to decrease the temperature variation and allows the future baby to move and travel through the maternal uterus.

The amount of amniotic fluid changes during pregnancy. It increases until week 34 of pregnancy when it reaches its maximum and from that moment on, it decreases until birth. Some women have problems related to the amount of amniotic fluid. These are some examples:

  • Polyhydramnios: it is an alteration in which the amniotic sac has an excessive amount of amniotic fluid owing to an excessive increase of amniotic fluid. The main causes of this alteration may be gastrointestinal disorders, which prevent the intake or absorption of normal amount of amniotic fluid, lung disorders, neurologic problems, gestational diabetes, congenital abnormalities, or multiple pregnancies.
  • Oligohydramnios: it is an alteration in which the amniotic fluid volume in the amniotic sac decreases so that it is an unsuitable amount for such month of gestation.

The main causes of this alteration are usually foetal abnormalities, rupture of membranes, defects of the kidneys, lungs or urinary tract, post-term pregnancies, and placental dysfunction.

Authors and contributors

 Cristina Mestre Ferrer
BSc, MSc
Embryologist
Bachelor's Degree in Biological Sciences, Genetics & Human Reproduction from the University of Valencia (UV). Master's Degree in Biotechnology of Human Assisted Reproduction from the UV and the Valencian Infertility Institute (IVI). Embryologist at IVI Barcelona. More information