Calcium Intake in Middle- and Upper-Income Pregnant Women Throughout the Course of Gestation

Abstract

The average daily calcium intake from food and supplements was determined for a group of middle- and upper-income pregnant women throughout gestation. The daily calcium intake was compared to the newly developed Dietary Reference Intake - Adequate Intake (DRI–AI) of 1000 mg calcium/day for women aged 19-50 years. Fifty-seven women were enrolled at their first prenatal visit, a 24-hour recall was obtained, and a diet instruction was given to ensure that subjects of different obstetricians received consistent nutrition education. A series of 3-day diet records was collected, one for each month of gestation. An additional 24-hour recall was obtained in each trimester. The data were separated into initial 24-hour recall (24 H) which was obtained before the diet instruction, first trimester diet records (T1), and second and third trimester diet records pooled with appropriate 24-hour recalls (T2 and T3, respectively). The average dietary calcium intake (mg) was significantly different between the trimesters (mean±SEM: 24 H=817±54, T1=1127±80, T2=1066±62, T3=1120±95, p<0.05). Of the fifty-seven women, 49 took calcium-containing supplements at least once. Total calcium from food and supplements was significantly different between the trimesters (mean±SEM: 24 H=1015±67, T1=1519±95, T2=1438±103, T3=1443±160, p<0.05). When comparing calcium intake from food, the percentage of women who consumed less than the recommended 1000 mg calcium/day was: 75% in 24 H, 42% in T1, 57% in T2, and 46% in T3. Energy intake and the incidence of nausea were significantly different between trimesters, with an increase in nausea and a decrease in caloric intake in 24 H. In conclusion, calcium intake increased after the initial physician visit, which could be due to a decrease in nausea, an increase in caloric intake, or adjusted intake secondary to the diet instruction.