Premature rupture of the membranes (PROM) and intrauterine infection (IUI)

When labour is normal, regular contractions start and the patient's cervix begins to dilate before her membranes rupture and amniotic fluid escapes. Sometimes, her membranes rupture first, before contractions start, either before 36 weeks (preterm rupture), or at term (prelabour rupture). When her membranes rupture early the risks are: (1) Intrauterine infection or ''IUI', which is much the most important but is usually not common, and (2) premature labour.

Are you going to induce her or not? The advantages of expectant treatment (not inducing her) are that: (1) It increases the maturity of the fetus, which is important if she is less than 36 weeks. (2) It avoids the risks of induction, which are: (a) Failure, which means that you will have to section her, because you will have done repeated vaginal examinations. (b) The complications of oxytocin (18.4a). The disadvantage of expectant treatment is the risk of infection (chorioamnionitis) which may kill her and her baby. You can minimize this risk by: (1) Totally avoiding vaginal examination with your fingers until contractions are well established. (2) Avoiding speculum examinations as much as possible. (3) Practising reasonable vulval hygiene. (4) Observing her carefully for signs of infection, and inducing her and giving her antibiotics at the very first sign of infection.

Many obstetricians feel that IUI is such a serious risk, after premature rupture of the membranes, that it far outweighs any benefit that might follow from expectant treatment. What are you going to do? If there is little puerperal infection in your hospital, you can manage mothers expectantly. If puerperal infection is common, both mother and child are best delivered within 24 hours. Fortunately, labour usually starts successfully within this time. If in doubt, induce!

Midwives often justify vaginal examinations by saying that they are necessary to exclude prolapse of the cord. Tell them that: (1) The risk of prolapse of the cord is small, but the risk of infection is great. (2) Cord prolapse will only harm the baby, but infection will endanger his mother also. (3) If her cervix is sill closed, as it often is, vaginal examination will not rule out cord prolapse. Teach them that premature rupture of the membranes calls for the suppression of vaginal curiosity!

Avoid steroids, and give antibiotics only on the indications below.

PREMATURE RUPTURE OF THE MEMBRANES The patient complains of loss of fluid from her vagina, before the onset of regular painful contractions. If you are not sure of her dates, estimate them from her fundal height using Fig. 19-15. This is not precise, but it may be the best you can do.

EXAMINATION. Start by separating her labia and asking her to cough: Is liquor discharging from her vagina? Is urine coming from her urethra?

If you don't see any fluid, repeat the examination after a few hours, so as not to miss intermittent loss of liquor from a small leak. Do one sterile speculum examination, to make sure that her membranes have ruptured, and that she really is draining liquor. Make sure that a senior person does this, so that it need not be repeated. Ask her to cough: you may see it escaping from her cervix. Observe: (1) The dilatation of her cervix. (2) Its degree of effacement. (3) Confirm the presenting part[md]you may see it if her cervix is open. (4) Exclude prolapse of the cord.

CAUTION ! Don't do a vaginal examination with your fingers: the risk of infection is too high.

Alternatively, avoid this examination, and merely ''wait and see'. If she continues to lose fluid (as shown by checking her pads), she has obviously ruptured her membranes. One contributor does not advise a speculum examination, because he finds that he can manage without it.

If you are not quite sure if the fluid that is draining is liquor or urine: (1) smell it, (2) test its pH (urine and vaginal discharge are acid, amniotic fluid is alkaline), and (3) leave some to dry on a slide. Look at it under a microscope. Liquor, but not urine, or a discharge, will dry as a pattern of ferns. If you have not done this test before, try it with some known liquor.

THE MANAGEMENT [s7]OF PRETERM RUPTURE OF THE MEMBRANES If the diagnosis is confirmed or suspected, admit her, provide her with a clean perineal pad or cloth, make sure she keeps her vulva and perineum clean, check her temperature 4- hourly, and inspect her liquor daily. See also ''Stop Press'.

If no liquor can be seen escaping after 5 days, the diagnosis is not confirmed, so discharge her. 25% of patients stop leaking liquor in 5 days and can be discharged. 75% go into spontaneous labour during this time.

If she is less than 28 weeks, with a live baby, and has no signs of IUI, opinions differ on what you should do. Much depends on how common puerperal sepsis is in your hospital: see above. The chances of her pregnancy continuing long enough for the fetus to survive are small, but not zero. If you are worried about the risk of infection, induce her. If the risk of infection seems small, leave her. She will probably go into labour soon, but she might be lucky, and her pregnancy may continue.

If she is 28[nd]36 weeks and her membranes have been ruptured for less than 48 hours, and she has no IUI, wait 48 hours. If her liquor stops draining, don't intervene. If it continues to drain at 48 hours, induce her, if the risk of infection in your hospital is high. If it is not so high, wait until the fetus is more mature at 36 weeks. Culture her amniotic fluid at delivery. One contributor waits 5 days, by which time nearly all mothers have gone into labour, or stopped draining.

;$9If she is [mt]36 weeks. If labour does not start spontaneously in 24 hours, induce her with oxytocin.

CAUTION ! Be sure to induce her if: (1) Her baby is dead at any stage of pregnancy. (2) She has signs of IUI at any stage of pregnancy. (3) She is more than 36 weeks, and has not gone into labour spontaneously in 24 hours. (3) Infection is common in your hospital.

CAUTION WITH OXYTOCIN ! Remember the precautions for the use of oxytocin (18.4a): (1) Don't give her an oxytocin drip if there are any contraindications to its use (M 22.2). CPD is unlikely to be a problem in preterm babies. (2) If she is a grand multip, avoid oxytocin, and await the spontaneous onset of labour. (3) If she has signs of IUI, use oxytocin with extreme caution, and stop the drip as soon as she is having regular contractions, or you section her. IUI increases the dangers of section, so balance the risks as best you can.

INTRAUTERINE INFECTION, ''IUI' DIAGNOSIS. IUI causes these signs in this order: (1) Fetal tachycardia. (2) Maternal pyrexia and tachycardia. (3) Uterine tenderness. (4) Offensive, blood-stained liquor.

TREATMENT. She will probably be septicaemic, and may be in septic shock (53.4). If necessary, resuscitate her with intravenous fluids. Give her broad-spectrum intravenous antibiotics; chloramphenicol and metronidazole are suitable (2.9). Empty her uterus as soon as possible, whatever the duration of pregnancy. It will often empty spontaneously. If it does not, give her an oxytocin infusion with caution, and stop the drip as soon as she has regular contractions. Her baby usually dies, if he is not already dead when she becomes infected.

DIFFICULTIES [s7]WITH INTRAUTERINE INFECTION If bubbles of GAS come from her cervix, or you feel crepitus of her cervix or abdominal wall, she has GAS GANGRENE. Her uterus and abdominal wall may be distended with gas. Give her large doses of penicillin, chloramphenicol, and metronidazole, as in Section 54.13, and evacuate her uterus. If the infection has spread to the wall of her uterus, consider hysterectomy.