bubble_chart Overview

The rupture of membranes before labor is called premature rupture of membranes (PROM). The reported incidence varies, accounting for 2.7% to 17% of all childbirths. It occurs approximately 2.5 to 3 times more frequently in premature labor than in full-term deliveries. Its adverse effects on pregnancy and childbirth include an increased rate of premature labor, higher perinatal mortality, and elevated rates of intrauterine and puerperal infections.

bubble_chart Etiology

Trauma; cervical incompetence; pregnancy late stage [third stage] sexual intercourse causing mechanical stimulation or leading to chorioamnionitis; lower genital tract infections, which can be caused by bacteria, viruses, or toxoplasma; increased intra-amniotic pressure (such as multiple pregnancy, polyhydramnios); poor engagement of the fetal presenting part with the pelvic inlet (such as cephalopelvic disproportion, abnormal fetal position, etc.); poor development of the fetal membranes leading to thinness and fragility.

bubble_chart Clinical Manifestations

A pregnant woman suddenly feels a large amount of fluid flowing out from the vagina, followed by intermittent small discharges.

The impact on the mother and baby includes that premature rupture of membranes can cause mental stress for the mother, may induce premature labor, and increase the risk of intrauterine infection and puerperium infection. For those who give birth more than 48 hours after membrane rupture, the maternal infection rate is 5–20%, and the sepsis rate is

1. 145, with a maternal mortality rate of about 1

︰5500. The fetus may inhale infected amniotic fluid, leading to fetal pneumonia or fetal distress; even asymptomatic cases may result in congenital neonatal pneumonia after childbirth. The chance of umbilical cord prolapse also increases. Reports indicate that the neonatal mortality rate after correction for early membrane rupture is 1.7%. The closer to full-term pregnancy, the higher the likelihood of labor onset after membrane rupture. Generally, membrane rupture does not affect the progress of labor.

bubble_chart Diagnosis

When intra-abdominal pressure increases, such as during coughing, sneezing, or heavy lifting, amniotic fluid leaks out. If the amount of fluid increases when the fetal presenting part is pushed upward during a rectal examination, a definitive diagnosis can be made.

1. Vaginal fluid pH test: Normally, vaginal fluid has a pH of 4.5–5.5, amniotic fluid has a pH of 7.0–7.5, and urine has a pH of 5.5–6.5. When tested with nitrazine paper, if the vaginal fluid is alkaline with a pH ≥7.0, it is considered positive, strongly suggesting amniotic fluid and a high likelihood of premature rupture of membranes.

2. Vaginal fluid smear examination: If a dried smear of the fluid shows fern-like crystals, it indicates amniotic fluid. A smear stained with 0.5‰ methylene blue reveals pale yellow or unstained fetal skin epithelium and lanugo hair; staining with Sudan III shows orange-yellow fat globules, and staining with 0.5% Nile blue sulfate reveals yellowish fetal epithelial cells. These results are more reliable than pH paper testing and confirm the presence of amniotic fluid.

3. Amnioscopy: Direct visualization of the fetal presenting part without seeing the forebag of amniotic fluid confirms the diagnosis of premature rupture of membranes.

bubble_chart Treatment Measures

1. Pregnant women with premature rupture of membranes should be hospitalized for delivery, closely monitoring fetal heart rate changes. Those without engagement of the presenting part should rest absolutely in bed, preferably in a lateral position, to prevent umbilical cord prolapse. For those already in labor, the progression of labor should not be hindered.

2. If there is chorioamnionitis, efforts should be made to expedite childbirth regardless of gestational age. If the pregnancy is near term or infection is evident, a cesarean section should be considered.

3. If labor has not begun and there are no signs of infection, and the fetus has reached full term (37 weeks of pregnancy with a fetal weight of at least 2500g), observation for 12–18 hours is advisable. If labor does not start spontaneously, induction or cesarean section should be initiated based on the circumstances.

4. If gestational age is less than 37 weeks, with no signs of labor or infection, maintain perineal hygiene and monitor closely to appropriately prolong the pregnancy.

5. If the pregnancy is preterm but labor has begun with a cephalic presentation, vaginal delivery may be attempted.

6. If the pregnancy is preterm but beyond 30 weeks, and breech labor has started, a cesarean section should be considered. However, if the mother disagrees, it should not be forced. For pregnancies less than 30 weeks, vaginal delivery is preferable.

7. After childbirth, antibiotics should be administered to control infection.

bubble_chart Prevention

Actively prevent and treat lower genital tract infections, and emphasize hygiene guidance during pregnancy; prohibit sexual intercourse in the late stage of pregnancy [third stage]; avoid heavy lifting and abdominal impact; for those with cervical incompetence, bed rest is recommended, and cervical cerclage should be performed around the 14th week of pregnancy, with the cerclage site as close as possible to the level of the internal cervical os. Regarding whether to prophylactically administer antibiotics after membrane rupture, most scholars believe that prophylactic use of Yaodui has minimal effect on reducing maternal morbidity and does not reduce perinatal morbidity or mortality. Additionally, antibiotics crossing the placenta may lead to neonatal drug resistance in the future, hence active postpartum treatment is advocated, which is superior to prophylactic antibiotic use.