Effects of iron and folate supplementation on haematological parameters, birthweight and neo-natal growth in a highland population of Kenya

Abstract

Anaemia during pregnancy as a result of iron and folate deficiencies is a major threat to women, particularly in developing countries. Because of the extra demands that pregnancy imposes on iron and folate status of the mother, and because of the traumatic effects of such deficiencies, WHO recommends supplementation of these micronutrients. This study evaluated the effects of iron and folate supplementation in 100 healthy, pregnant outpatients of the Kikuyu Hospital outside Nairobi. The subjects were similar with respect to ethnicity and socioeconomic factors. Subjects were divided into 4 groups in a randomized, double-blind trial. Group A received a placebo, group B a combination of 150 mg. iron and 0.5 mg. folate, group C folate only and group D iron only. Supplements were given in slowrelease capsules. Participants were non-anaemic (Hb > 10 gjdl) and 25-30 weeks pregnant on enrolment. Treatments were given for a minimum of 4 weeks before delivery and patients were also encouraged to continue taking the capsules until 4 weeks post-partum. Haematological indices of haemoglobin (Hb), haematocrit (Hct), mean corpuscular volume (MeV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), erythrocyte morphology, as well as birthweights and neonatal weight gain were used to evaluate the effects of the supplementation. The higher than expected attrition rate may be due to reasons of fees payable at the hospital, distances for some patients to travel and perhaps iv choosing to deliver elsewhere at the last minute. At the time of enrolment, 27% of the women showed macrocytosis. Diet had no association with initial Hb or the change in Hb during the study. However, 52% of women who showed initial macrocytosis were consuming a diet poor in iron and folate. The average birthweight was 3178 grams. None of the treatments had any association with birthweights. The two factors that affected birthweights were mothers' initial weight at the time of enrolment and mothers' weight gain during the last trimester. Folate supplementation had no significant effect on parameters tested. When age, parity, height, diet and socioeconomic factors were adjusted for, only the group receiving iron alone showed a significant rise in Hct and Hb (p < 0.005). Iron is an essential supplement during pregnancy in most communities. The highland population of Kenya generally have a diet rich in iron and folate compared with many other African peoples. As a consequence, pregnancy anaemia may not be a major public health problem in this population. Although the results of this study support the routine supplementation with iron during pregnancy in this highland population, the benefit of additional folate was not clear and further studies evaluating iron and folate status during pregnancy and possible influencing factors in this region are recommended.