Maternal basal metabolic rate in twin pregnancy.

OBJECTIVE: This study examined the basal metabolic rate in patients with twin pregnancies and compared the results with those of singleton pregnancies and non-pregnant women.

METHODS: In 15 non-pregnant women, 14 patients with twin and 25 patients with singleton pregnancies, the resting energy expenditure was measured using an open-circuit ventilatory system during the third trimester of pregnancy.

RESULTS: The averaged resting energy expenditure in patients with twin pregnancy was 1,636 +/- 174 kcal/day, significantly higher than that in patients with singleton pregnancy (1,456 +/- 158 kcal/day; p < 0.05). Both of these levels are significantly higher than those in non-pregnant women (1,228 +/- 132 kcal/day; p < 0.05).

CONCLUSION: Our results indicate that the estimated increased metabolic demands in patients during the third trimester of twin pregnancy are about 10% higher than those in women with singleton pregnancy. A prospective clinical study concerning nutrition counseling is needed.