An ectopic pregnancy occasionally aborts backwards down a tube, or bursts out of it without killing the patient, and embeds itself elsewhere in her abdominal cavity. Sometimes, an ovum is fertilized outside a tube on the surface of an ovary, and then implants itself in the abdominal cavity. Such an ectopic may die at any stage, or proceed to term. An abdominal pregnancy is thus a rare complication of an ordinary ectopic pregnancy, so that in areas where ectopic pregnancies are common, the incidence of abdominal pregnancies is increased also. An abdominal pregnancy causes comparatively few symptoms. None of them are individually diagnostic, so the diagnosis depends on the sum of many clues, none of which is enough by itself.
A patient with an abdominal pregnancy may present with: (1) Persistent abdominal pain from about 26 to 28 weeks onwards of variable severity, which is not well localized. (2) Her ''uterus' (in reality the gestational sac) is ill-defined, and feels ''odd', when you palpate it. The fetal parts may be abnormally easy or abnormally difficult to feel. The lie of the baby is often abnormal, and may be persistently transverse or oblique. (3) The features of (1 and 2) accompanied by the failure of her ''uterus' to enlarge, typically at 32 weeks, and a dead baby. (4) The features of (1 and 2) combined with a ''uterus' that distends more than it should, so that you suspect polyhydramnios. (5) Postmaturity ([mt]40 weeks). (6) A dead baby which she does not expel, either spontaneously or with oxytocin (16.4).
Less commonly, she may present with: (7) An abdominal mass after 26 weeks adjacent to an empty uterus (or a uterus enlarged to the size of a 12- to 16-week pregnancy), which is quite separate from it. (8) A distended abdomen which is like a full term pregnancy, and a mass which is less cystic and rubbery than a normal pregnancy. She says she is pregnant,, but is having normal periods. On questioning she admits having missed some periods, possibly nine, in the past. (9) Loss of weight and general ill health.
The diagnosis depends on recognizing (a) that she is pregnant and (b) that her pregnancy is not in her uterus. Her history is seldom helpful, but: (1) She may have had episodes of pain in early pregnancy. (2) She may have a history of a previous ectopic pregnancy. (3) If she is an experienced multip, she may say that her pregnancy ''feels different'.
The fetus can implant itself anywhere, but because the placenta is so large, it is always attached to gut or omentum somewhere. The common sites are: (1) In her pouch of Douglas. (2) In her broad ligament, where it is attached to her uterus, or the wall of her pelvis. (3) On an ovary.
MARY (19 years) was observed to have a transverse lie at 7 months. External version failed, so she was allowed to go to term. At 40 weeks she had abdominal pains, but the lie was still oblique. On pelvic examination her cervix was in a curious position in front of the fetal head. At Caesarean section she did not seem to have a uterus, instead her membranes were close against her abdominal wall. After a live baby girl had been delivered, the placenta was found to be attached to her left Fallopian tube. It was left in place and as many of the membranes as possible removed. She recovered uneventfully. LESSONS (1) If something rather unusual happens, think of the possibility of an extrauterine pregnancy. (2) If you cannot easily remove the placenta, leave it. Fig. 16-7 AN ADVANCED EXTRAUTERINE PREGNANCY in the omentum. A, tying off the vessels in the omentum. B, removing the fetus. C, in this patient the entire sac is being removed; if it is not easy to remove, leave it. From Bonney's ''Gynaecological Surgery'. Balli[gr]ere Tindall, with kind permission.
ABDOMINAL PREGNANCY X-RAYS. (1) The fetus may be in an abnormal attitude and remain in it over a long period. (2) In a standing lateral film the fetal parts may overlap the shadow of the patient's spine. This is rare in a normal pregnancy. Ultrasound in the hands of an experienced operator is very helpful, so refer her for it if you can.
MANAGEMENT. If you make the diagnosis before 24 weeks, a laparotomy is usually indicated. This is difficult, so try to refer her.
If the pregnancy is more than 24 weeks and the baby is still alive, consider leaving him until 34 to 36 weeks, so as to improve his chances of survival. Often, she has few children or none, and is grateful for a live child. If you decide to do this she may bleed before term (uncommon), so keep her in hospital to wait.
If the pregnancy is more than 24 weeks but the baby is dead, postpone the operation for 3 or 4 weeks after the fetal movements have stopped, so that the vascularity of the placental bed is reduced. If he has been dead for more than 4 to 6 weeks, check her clotting time before you operate, because of the possibility of DIC (19.11b).
If he has been dead for more than a month, book her for the next operating list, whatever the duration of pregnancy. There is always a danger that he may become infected. Check her clotting time.
If she has sudden pain at any time, it may indicate rupture of the membranes or haemorrhage, so operate immediately.
REMOVING AN ABDOMINAL PREGNANCY This is an expert's task, so refer her if you can. If you have to operate yourself, prepare for much bleeding. You will need at least 2 units of blood and preferably more.
ANAESTHESIA. General anaesthesia with tracheal intubation.
INCISION. Listen over her abdominal wall for a vascular bruit (sound). This may tell you where the placenta is getting its blood from. If you hear one, place your abdominal incision over some other part of her abdominal wall. If you can feel the baby close under it, this may be a good site to incise. If there is no obvious site to be preferred or avoided, make a paramedian or midline incision, if necessary above the umbilicus. Open her abdomen with care, because her gut may have stuck to her abdominal wall.
Search for the amniotic sac and placenta. Open the sac through a thin area where there is no placenta. If necessary, remove any gut and omentum from the front of the sac. Dissect away the sac and remove the baby. Clamp and tie his cord firmly.
If he was alive when he was removed, leave the placenta.
If he was dead, and: (1) the placenta is not fixed to her gut, or some other essential structure, and (2) you think you could shell it out quite easily, then remove it. But if it is fixed to the gut or some other vital structure, or to her mesentery or to her parietal peritoneum over a large area, leave it. Disturbing it will cause severe bleeding.
If the pregnancy has arisen in a tube or ovary, and the sac has a vascular pedicle which you can clamp, divide the pedicle and remove the sac completely with the placenta.
CAUTION ! (1) Don't dissect in the region of the placenta. This may cause catastrophic bleeding, especially if he is still alive. (2) Take care not to injure the mesentery, or its blood supply, or part of her gut will necrose, and she will die from peritonitis. (3) Take special care not to injure her large gut!
If you decide to leave the placenta, cut and tie the cord as short as possible. Then remove as much of the sac as you safely can. Don't insert a drain, the placenta is going to be absorbed anyway, and a drain might only introduce infection. Close her abdomen (9.8).
DIFFICULTIES [s7]WITH ABDOMINAL PREGNANCIES If you CANNOT CONTROL BLEEDING in any other way (rare), you may have to send her back to the ward with clamps in place protruding from the wound, and then cautiously remove them later (3.1). Or, pack the bleeding area, and then gently withdraw the pack later (3.1).
If she presents with an ABDOMINAL MASS and a SINUS on her abdominal wall (rare), the sinus may be arising in an ectopic pregnancy. Probe it, you may feel fetal bones. Open it with great care not to injure her gut.