17.1 Anaemia in pregnancy

Severe anaemia in pregnancy makes a mother sick, and in some parts of the world it commonly kills her as the result of congestive heart failure, before, during, and after labour. Anaemia impairs her resistance to genital and respiratory infection, and the cerebral anoxia it causes can lead to mental confusion and coma. How ill she is depends on how rapidly her anaemia developed. If it developed slowly, she may have suprisingly few symptoms. Even so, a traumatic delivery or a small blood-loss can kill her. Severe anaemia can also harm her baby by causing late abortion, prematurity, low birthweight (IUGR, 19.13), and perinatal deaths. Even moderate anaemia harms him, and severe anaemia can cause a perinatal mortality of thirty per cent.

Mild anaemia (down to 100 g/l) is physiological and is the result of the plasma volume expanding during pregnancy. More severe anaemia is caused by: (1) P. falciparum malaria, especially in primips. (2) Iron deficiency, especially in grand multips, and in patients with hookworms. (4) Folate deficiency, especially if they also have malaria, malnutrition, or twins. (3) Sickle-cell disease and other haemoglobinopathies. (4) AIDS. Fortunately, anaemia is also cheaply preventable, and fairly easily treated; if this is done promptly, it will remove most of its risks to her and her baby. So find out what the causes are in your area and adapt the regime below to them. You will need to measure her haemoglobin. The most practical instruments for doing this at the present time are the Spencer haemoglobinometer (AOC) and the microhaematocrit centrifuge.

Unfortunately, you may see her for the first time late in pregnancy, when she may need blood. The risk of transfusion is that it will increase her blood volume, and may precipitate cardiac failure. You can minimize this risk by giving her packed cells only, by transfusing her slowly, and by giving her a rapidly acting diuretic.

Figure 17.1: THE PATHOPHYSIOLOGY OF ANAEMIA, malaria, iron- and folate deficiency in pregnancy. Kindly contributed by Alan Fleming, from a Distance Learning Module prepared by the Wellcome Tropical Institute.

The prevention of anaemia in pregnancy is a community problem. Births must be spaced, parasites controlled, nutrition improved, and prophylactic treatment given to all mothers from the beginning of pregnancy.

Malaria especially falciparum malaria: (1) Destroys red cells and so causes anaemia, which may be megaloblastic if she also has a secondary folate deficiency. (2) Causes abortions, perinatal deaths, premature labour, and low birthweight (IUGR, 19.13). If she is non-immune, her placenta may be so heavily parasitized that it is black with malarial pigment. Malaria may be more serious in areas where it is unstable, than in those in which it is stable. In an area of stable malaria, she may only get attacks when she is pregnant, especially during the second trimester, and while she is a primip.

Antimalarials have their risks. In a village mother in an endemic area the risks lie strongly with the parasite—she needs prophylaxis, either from the antenatal clinic, or through PHC workers—if you can get them the drugs. For a minimally exposed visitor to an endemic area, you will have to balance the risk of malaria against those of the drugs to prevent it.

Chloroquine gives the best and safest protection against sensitive strains of P. falciparum, and all the other malaria pa­ra­sites. Proguanil is safe in pregnancy. Although the antifolate pyrimethamine is theoretically embryopathic, it seems to be safe in practice. One contributor considers it should be supplemented with folic acid, especially during the first trimester. Avoid ’Fansidar’ (pyrimethamine/sulphadoxine) except for the treatment of chloroquine-resistant strains (see below). ’Maloprim’ (dapsone/pyrimethamine) is controversial; one tablet a week gives fairly good protection if there is little resistance locally to pyrimethamine, and is said not to be embryopathic. One contributor considers it should be supplemented with with folic acid.