<unk>  <unk>  or amniorrhexis is a term used during pregnancy to describe a<unk>  of the amniotic sac. Normally, it occurs spontaneously at full term either during or at the beginning of labor.<unk>  of the<unk>  is known colloquially as "breaking the water" or as one's "water breaking." A premature<unk>  (PROM) is a<unk>  of the amnion that occurs prior to the onset of labor. This typically occurs before the pregnancy's 37 week gestation. In the United States, more than 120,000 pregnancies per year are affected by a premature<unk> , which is the cause of about one third of preterm deliveries. Sometimes, a child is born with no<unk>  of the amniotic sac (no<unk> . In such cases, the child may still be entirely within the sac once born; such a birth is known as an en-caul birth.
Rupture of membranes
Artificial rupture of membranes
Placental expulsion
Pneumonolysis
Placental infarction
Uterine inversion
Amniotic fluid embolism
Uterine perforation