Before a baby is born, the
amniotic sac breaks open, causing amniotic fluid to
gush out or, less commonly, to slowly leak. When this happens before
contractions start, it is called premature rupture of membranes (PROM). PROM
can occur at any time during pregnancy.
When PROM occurs before 37 completed weeks of pregnancy, it usually
leads to
preterm labour. You may hear this early PROM referred
to as preterm premature rupture of membranes, or
pPROM.
PROM is often unexpected, and the cause is often difficult to
identify. Known causes of PROM include:
- Uterine infection, which is a common trigger of
PROM.
- Overstretching (distension) of the uterus and amniotic sac.
Multiple fetuses or too much amniotic fluid (polyhydramnios) are common causes
of distension.
- Trauma, as from a motor vehicle accident.
Course of pPROM
Preterm labour usually begins shortly after pPROM occurs.
Sometimes, when a slow leak is present and infection has not developed,
contractions may not start for a few days or longer. Generally, the later in a
pregnancy PROM occurs, the sooner the onset of labour. Labour begins:1
- Within 24 hours in 50% of pPROM
cases.
- Within 7 days in 75% to 90% of pPROM cases.
On occasion, a leak high up in the amniotic sac may reseal itself
so that preterm labour does not start or subsides.
In rare cases, a pregnancy can be carried to term if pPROM occurs
in the second trimester.
Standard treatment for pPROM
Standard treatment for pPROM includes antenatal
corticosteroid medications, which are used to speed up
fetal lung maturity before 34 weeks of pregnancy.
Other treatment for pPROM
Other treatment for pPROM may include:
- An observation period.
- Antibiotics, given to treat or prevent amniotic fluid
infection.
- Amniocentesis, which is sometimes used to check for
infection in the uterus.
- Starting (inducing) labour with
medication if labour does not start naturally. This is meant to speed up
delivery and reduce the risk of infection. Labour can be induced if there is
strong evidence that the fetus's lungs are mature enough, or if you have an
infection.
Controversial treatment for pPROM
After amniotic membranes have ruptured,
tocolytic medication is less effective in slowing or
stopping preterm labour contractions. However, tocolytic medication is
sometimes used to delay a preterm birth long enough for antibiotics and
antenatal corticosteroid medication to work (24 hours) or long enough to
transport the mother to a hospital that has a neonatal intensive care unit
(NICU).2