“Doc, My Water Bag Burst!” Prelabour Rupture of Membranes (PROM)

C was bathing when she suddenly felt a gush of clear watery fluid flowing out of her vagina. Taken aback, she quickly finished her bath and alerted her husband who rushed her to the hospital.


C, a 28-year-old financial executive was a first-time mum at her 33 weeks of gestation. She was seen early in the first trimester and her antenatal checkups had been normal. She was a non-smoker and there was no history of vaginal bleeding. She did not engage in vigorous exercise or sexual activity recently.


C looked anxious on examination. Her body temperature, blood pressure and pulse rate were normal. Ultrasound scan of the abdomen revealed that her foetus appeared normal and weighed about 1.7 kg. The fetal heart was beating at 156 beats per minute. The amount of amniotic fluid surrounding the foetus was normal. There were occasional painless Braxton-Hicks uterine contractions.


Speculum examination of the vagina found a pool of clear fluid in the posterior recess of the vagina. This was confirmed to be the amniotic fluid by the swab test (Amnicator) which showed a pH value of 7.1. C had ruptured her water bag before the onset of labour, a condition known as prelabour rupture of membranes or PROM. As this occurred before 37 weeks of gestation, it is called “preterm PROM”.


How often is Preterm PROM?

Preterm PROM occurs in about three in a hundred pregnancies and is associated with 30 to 40 % of preterm births


What are the causes and risk factors of preterm PROM?

The cause in most cases is not known. Risk factors include:

  • Having a short cervix (neck of the womb).

  • Infection of the reproductive organs.

  • History of preterm birth in a previous pregnancy.

  • Vaginal bleeding during pregnancy especially in the second and third trimesters.

  • Smoking or taking illicit drugs during pregnancy.

  • Low socioeconomic status.

Why is preterm PROM a concern?

Preterm PROM complicates as many as one third or more of premature births. About 50% of babies will deliver within one week after the membranes rupture. A preterm baby has many serious life-threatening problems (see the article “premature birth” on our website). Other complications of PPROM include:

  • Serious infection to the mother and the baby as a result of Infected amniotic fluid and placental tissues (chorioamnionitis).

  • Premature separation of the placenta from the uterus (abruptio placentae).

  • Compression of the umbilical cord.

  • Increased incidence of Cesarean section.

  • Infection after delivery.

What are the symptoms of Preterm PROM? How is it diagnosed?

The typical symptom is a sudden gush of fluid from the vagina. Other symptoms include:

  • Uncontrollable leaking of fluid per vagina

  • Feeling of wetness in the vagina or underwear

Most cases can be diagnosed on the basis of the patient's history and speculum examination of the vagina. Vaginal fluid is then tested for the pH value with the nitrazine-based swab test. Amniotic fluid can also be dried on a glass slide and a fern-like pattern may appear under microscope.


How is Preterm PROM treated?

Treatment depends on the severity of the condition and the stage of pregnancy. It includes:

  • Bed rest in hospital to monitor the mother for signs of labour and infection. The baby should also be monitored by ultrasound for its well-being and heart rate.

  • Antibiotics are given to prevent and treat the infection.

  • Steroids may be given to help the baby’s lungs grow and mature.

  • Tocolytic medicines may be given to stop labour contractions.

  • Timing and mode of delivery will depend on the severity of infection, the presence of obstetrical complications, the viability of the baby and the pediatric medical support.

C was admitted for rest with an expectant management. Steroid and antibiotics were administered. She was monitored for signs of infection by regular blood tests. Foetal wellbeing was assessed with foetal heartbeat monitoring (CTG) and ultrasound scan. One week after admission, she began to show signs of an intrauterine infection. A Caesarean section was done and a healthy baby boy weighing 2 kg was delivered. He was monitored in the NICU (neonatal intensive care) for 3 days and was discharged well.

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