Seasonal variation of birthweight in Bangladesh.

Analysis of birthweights of 1772 singleton babies born alive at Kumudini Hospital in rural Bangladesh over 2 consecutive years, 1983 and 1984, showed a consistent seasonal variation. The highest birthweights occurred in the period March to May (summer) and the lowest in the September to November period (autumn). This could not be correlated with differences in maternal age or parity, but was correlated with seasonal availability of food and changes in children's nutritional status as recorded in the hospital under-5s clinic. It is concluded that poor maternal nutrition in the last trimester of pregnancies in mothers delivered in the September to November period is the main factor, and recommendations for health education are made accordingly.