Twinning rates in Fiji

Summary The incidence of twins in Fiji has been investigated using birth registrations for the years 1976–81. The twinning rate for the indigenous Fijians is found to be 9–4 per 1000 live maternities, (based on 407 sets of twins), and for Indians, descendants of immigrants who began to arrive in Fiji in 1879, 6·2 per 1000 (based on 350 twins). After standardizing for maternal age, the difference between the two ethnic groups decreases slightly, but the Fijian rate remains almost 40% above that of the Indians. This difference is consistent over the 6 years of the study, is found for mothers of all age groups under 40 and at all levels of parity. An analysis of hospital records in Fiji produces higher twinning rates for both Fijians and Indians, but a similar difference is found between the two ethnic groups. Although the twinning rate for Fijians is lower than that reported for other Melanesian people, it is well above reliable rates found for Mongoloid races from whom the Fijian is descended. The sparse information on twinning rates among Polynesians suggests rates not dissimilar from Melanesians, so that no support for the hypothesis of low twinning rates in the Pacific is evident. The twinning rate for Indians in Fiji is lower than rates reported from the Indian subcontinent.