Heart failure in pregnancy

Where obstetric care is good, and the more easily preventable causes of maternal mortality have been eliminated, death from heart disease is one of the important remaining reasons why mothers die. Primary Mother Care warns staff in the antenatal clinic to be on the look out for mothers with heart disease, which usually presents as a cough, dyspnoea on exertion or at rest, malaise, oedema, or palpitations. Only rarely will a mother know that she has heart disease. It is most commonly due to anaemia, rheumatic carditis, or congenital heart disease. Fortunately, provided she is properly cared for, pregnancy does not influence the long-term outcome of her heart disease. One of the dangers is that she may suddenly go into failure, with little warning, in the last weeks of pregnancy, while in labour, or in the puerperium; so watch her carefully and treat her early.

Obstetrically, mothers with heart disease fall into these four groups:

Group One Mothers with heart disease, but no limitation of their physical activity.

Group Two Mothers with slight limitation of physical activity. They are comfortable at rest, but ordinary activity fatigues them and makes them short of breath.

Group Three Mothers who have marked limitation of their physical activity and are comfortable at rest, but less than ordinary activity gives them symptoms. They may show signs of heart failure.

Group Four Mothers who cannot do any physical activity without discomfort. They have symptoms at rest, obvious signs of heart failure, and any activity makes them worse. They are less likely to become pregnant, but if they do, delivery by any method may kill them.

The diagnosis of heart disease can be difficult, because systolic murmurs, oedema, and dyspnoea are common in normal pregnancy. Base your diagnosis of significant heart disease on: (1) Obvious cardiac enlargement. (2) Diastolic, presystolic, or continuous heart murmurs. (3) A harsh, loud, systolic murmur, especially if there is also a thrill. (4) Serious arrhythmia. (5) Signs of congestive failure[md]a raised jugular venous pressure, basal crepitations, ankle oedema, and an enlarged liver.

Fig. 17-4 A CARDIAC PATIENT IN LABOUR. A, during the first stage deliver her sitting up. B, during the second stage avoid the lithotomy position. Sit her up with her buttocks over the end of the bed. Ask two assistants (not shown) to support her with her legs resting on chairs. Discourage her from bearing down as much as you can.

HEART DISEASE GENERAL MEASURES. Try to ensure that a mother has as much rest as possible and avoids undue weight gain, fluid retention, infection, and anaemia. Keep her haemoglobin above 100 g/l. If necessary, transfuse her with packed red cells, and give her frusemide.

GROUPS ONE AND TWO. Allow her to go through pregnancy; see her regularly in the antenatal clinic: she is unlikely to go into failure.

GROUPS THREE AND FOUR. If possible, try to prevent her from becoming pregnant.

If pregnancy has not progressed beyond 12 weeks, opinions vary. (1) If she is well cared for, death from heart failure in pregnancy or labour is rare, so avoid termination. Some obstetricians working under ideal conditions never terminate a pregnancy for heart disease. (2) If care is less good, a therapeutic abortion might be indicated.

If she goes into failure during pregnancy, admit her for bed-rest and control it. Give her frusemide. If possible restrict the sodium in her diet. Digoxin is indicated if she has auricular fibrillation, otherwise its value is disputed. If failure is controlled, she can go home, provided you can keep in touch with her, and she and her family realize that she must rest.

DELIVERING [s7]A MOTHER IN HEART FAILURE Admit a mother with heart disease at 34 weeks, or earlier, if she goes into failure before then. For all degrees of heart disease vaginal delivery is likely to be safer than Caesarean section. Avoid section late in labour. If you expect complications, do it electively under general anaesthesia. Beware of cardiac failure developing after delivery as oedema fluid returns to her circulation.

If she has valvular disease, prevent endocarditis. Give her 3 doses at 8-hour intervals of: (1) ampicillin 500 mg orally or intramuscularly; and (2) gentamicin 80 mg intramuscularly. Or give her any other broad-spectrum antibiotic which is safe in pregnancy. Give the first dose when her membranes rupture, or you will encourage the growth of resistant organisms.

EQUIPMENT. Prepare for a cardiac emergency, and have digoxin, frusemide, aminophylline, and morphine ready. Also, a venesection set (M 13.4), tracheal tubes, a laryngoscope, and oxygen.

FIRST STAGE. Deliver her sitting up. Adequate analgesia is essential. Epidural anaesthesia is ideal, if you are skilled, because it decreases cardiac output. If this is impractical, give her morphine rather than pethidine.

Count her pulse and respiration rate every 30 minutes. If her pulse rises above 100 and her respirations above 24, and she is obviously dyspnoeic, she is in failure.

SECOND STAGE. Avoid the lithotomy position. Sit her up with her buttocks over the end of the bed. Ask two assistants to support her with her legs resting on chairs. Discourage her from bearing down as much as you can.

If she progresses quickly, allow her to deliver spontaneously. If her progress is slow, shorten this stage with outlet forceps or a vacuum extractor, or a generous episiotomy. Use enough local anaesthetic to prevent her feeling pain, and sit her up when you suture it.

Give her frusemide 40 mg intravenously, as soon as she is delivered.

THIRD STAGE. A small bleed is likely to benefit cardiac failure. So only give her ergometrine with oxytocin (''Syntometrine'), if she has lost more than 500 ml. If you give it when she has not bled, the sudden return of blood to her circulation from her contracting uterus may precipitate failure.

Watch her carefully for the next 24 hours, because this is the time when she is most likely to go into failure.

CAUTION ! (1) Don't overload her circulation, and avoid transfusion, especially after delivery. (2) Don't use local anaesthetics with adrenalin in them.

If you have used morphine, have nalorphine or naloxone ready for the baby. After delivery watch her pulse, temperature, and respiration carefully, and watch for puerperal infection. Advise her not to become pregnant again, and give her family-planning advice[md]preferably tie her tubes.

DIFFICULTIES [s7]DELIVERING A PATIENT WITH CARDIAC DISEASE If she goes into CARDIAC FAILURE which was not previously diagnosed or treated, give her intravenous morphine 10 to 15 mg, intravenous frusemide 40 to 80 mg, and if necessary apply rotating tourniquets (M 13.4). Give her oxygen through a nasal tube, and aminophylline 250 mg during 10 minutes timed by the clock. If she is fibrillating give her intravenous digoxin.

If her cervix is partly dilated and she is NOT IN SEVERE FAILURE, allow delivery to proceed vaginally. Interference of any kind is likely to make her worse.

If she is in SEVERE FAILURE AFTER FULL DILATATION, and you don't expect delivery in the next few minutes, deliver her with the vacuum extractor, or outlet forceps.