Mothers with a history of repeated first-trimester abortions are not easy to help. These are often the result of of some fetal abnormality for which nothing can be done. The best advice for them is to: ''Keep trying''. Most of them will eventually achieve a sucessful pregnancy.
Second-trimester abortions are different. They are not usually caused by recognizable fetal abnormalities. Some are due to maternal illness (syphilis, hypertension, diabetes, etc.), or to a congenital malformation of the uterine cavity. Others are caused by a somewhat mysterious condition called ''cervical incompetence'. As in the first trimester, often no cause can be found. The prognosis of a mother with repeated second-trimester abortions depends on the cause, and is excellent if syphilis can be treated, or cervical incompetence corrected surgically. Hypertension and diabetes are more difficult to treat, and the outcome of the pregnancy is less certain. Mothers in whom no cause can be found have a reasonable prognosis: about 70 per cent of their pregnancies go to term.
Here we are concerned with the management of patients with ''suspected cervical incompetence'. This means that the cervix opens spontaneously during the second trimester, without the uterus contracting. Sometimes this is due to a too-forceful dilatation during a ''D and C', or to a previous traumatic delivery. Usually, there is no obvious cause.
The diagnosis is difficult. It is usually made by the history alone. A typical patient gives a history of two or more spontaneous second-trimester abortions, without uterine contractions (until the membranes have ruptured), or bleeding. Her first symptom is a watery vaginal discharge, often followed by a sudden loss of amniotic fluid. Soon afterwards the fetus is delivered, sometimes still alive. The diagnosis is only certain in the present pregnancy if the uterus is found to be effacing and dilating, without any uterine contractions. When this is happening it is too late to insert a cervical suture[md]in this pregnancy.
Doctors differ greatly in the frequency with which they diagnose ''cervical incompetence'. True cervical incompetence is probably quite rare. If you make this diagnosis too often, you will suture many patients without cervical incompetence unnecessarily. This is undesirable, because inserting them is time-consuming, and they can cause complications. So only suture those patients with a highly suggestive history. Cervical incompetence never causes first-trimester abortions.
The simplest method is McDonald's, and is a variation of the original Shirodkar suture. If you do it on the right indications, it has a good chance of succeeding. Timing is critical. If you do it too early ([lt]14 weeks), the patient may get a first- trimester abortion due to a fetal abnormality, and the suture is wasted. If you do it too late ([mt]24 weeks), she may abort before you place ]]it. Don't insert a suture between pregnancies. This will cause more trouble than it is worth. As we go to press, Chalmers has reported that this method prevents one delivery before 33 weeks about every 20 times it is used, so its benefit is minimal.
SIFLOSA (20 years) had a McDonald suture inserted at 14 weeks, following three second-trimester abortions. Her pregnancy continued uneventfully until term, when she was admitted for delivery. Unfortunately, the consultant who inserted the suture was on leave, and it was not noticed by the duty team. She complained of severe pain during the second stage, but this was ignored. Labour proceeded normally, and she delivered a live baby without help. Immediately after delivery she complained of urinary incontinence and collapsed. No notice was taken of this, and she was discharged after 2 days. On examination 2 months later in another hospital she was found to have a high juxta-cervical 1 cm vesicovaginal fistula, which was contiguous with her cervix, which was torn and ragged. This was successfully repaired abdominally. LESSON (1) Always explain clearly to the patient that she must have the suture removed at 38 weeks or in labour. (2) Take her complaints seriously. Reported by Timothy Goodacre in ''Tropical Doctor'. Fig. 16-2 McDONALD'S CERVICAL SUTURE. A, the position of the suture. B, inserting it anteriorly. C, inserting it posteriorly. Partly from Bonney's ''Gynaecological Surgery', Bailli[gr]ere Tindall, with kind permission.
McDONALD'S CERVICAL SUTURE INDICATIONS. Two or more painless abortions between 16 and 28 weeks. The patient may have a scarred patulous cervix. Exclude syphilis, hypertension, and diabetes. If you see her between pregnancies, exclude abnormalities such as uterine septa (for which she needs a hysterosalpingogram) and fibroids, which can also cause second-trimester abortions.
CONTRAINDICATIONS. (1) Drainage of amniotic fluid or rupture of the membranes. (2) Vaginal bleeding. (3) Established premature labour. (4) Local infection. (5) Fetal anomalies if you can detect them. (6) An IUD or a missed abortion.
CAUTION ! Don't insert these sutures unless: (1) She has access to hospital. (2) It can guarantee that at all hours of the day and night there will be someone who will see her, who is competent to remove her suture. (3) You have explained to her what you are going to do, and that she must have her suture removed at 38 weeks, or when she goes into labour. (4) If she does go into labour with her suture in, it may cause a severe cervical tear, even worse cervical incompetence, a vesico-vaginal fistula or rupture of her uterus.
Preferably insert the suture at 14 weeks, when the danger of an early abortion is passed. Experts insert them up to 26 weeks, but never after 28 weeks. Check the fetal heart with Doppler ultrasound if you can. If you have an ultrasound scan, check that the fetus is alive, and confirm the gestational age.
ANAESTHESIA. (1) General anaesthesia is preferable. You must be able to retract her cervix and dilate her vagina widely to insert the sutures. (2) Ketamine.
METHOD. Insert a speculum. Grasp her cervix with sponge forceps. Insert a suture of No. 2 monofilament superiorly in the outer surface of her cervix, near the level of her internal os. Continue to place sutures in her cervix at regular intervals as shown, so as to encircle it. Then tighten the suture round it, so as to reduce its diameter to a few mm. The canal must be just patent as the suture is tied. If she is pregnant, don't insert a dilator. Admit her for 8 days; most failures occur in the first week.
Write on her notes in large red letters ''For removal of suture' at 36 weeks. See her every 2 weeks, and insert a speculum to check that the suture is still in place. Occasionally a stitch comes out and has to be reinserted.
At 36 weeks, or better, at 38 weeks (to avoid the respiratory distress syndrome in the baby) remove the suture, or remove it in early labour if she does not come in until then.
CAUTION ! Remove the suture immediately (rare) if: (1) The operation fails, and signs of imminent abortion develop. If you don't, her cervix may tear. (2) Her membranes rupture in the absence of labour. If you leave it in place, the risk of infection to both her and the baby may be increased.
If she has a tear at the side of her cervix, don't try to repair it. If she has signs of cervical incompetence, insert a McDonald's suture as above.
REMEMBER TO RECORD ''FOR REMOVAL OF STITCH AT 36 WEEKS'! Fig. 16-3 SITES OF IMPLANTATION. 1, the fimbria. 2, the ampulla (with the fimbria, the most common abnormal site). 3, the isthmus. 4, the uterine part of the tube. 5, the angle. 6, the body of the uterus, which is the normal site for implantation. 7, close to the internal os, leading to placenta praevia. 8, the cervix. 9, the ovary. 10, elsewhere in the abdominal cavity.