The effects of prophylactic iron given in prenatal supplements on iron status and birth outcomes: a randomized controlled trial.

OBJECTIVE: The hypothesis that daily use of a prenatal supplement with iron from enrollment to third trimester to initially iron-replete, nonanemic pregnant women would reduce third-trimester anemia and improve birth outcomes was tested. STUDY DESIGN: Eight hundred sixty-seven women in Raleigh, North Carolina, who were at < 20 weeks of gestation were enrolled; 429 of these women had hemoglobin levels of > or = 110 g/L and ferritin levels of > or = 40 microg/L and were assigned randomly to receive prenatal supplements with 30 mg of iron as ferrous sulfate (n = 218 women) or 0 mg of iron (n = 211 women) until 26 to 29 weeks of gestation. Intent-to-treat analysis was used for the outcomes of third-trimester iron status, birth weight, preterm birth, and small-for-gestational age. RESULTS: Mean birth weight was higher by 108 g (P = .03), and the incidence of preterm delivery was lower (8% vs 14%; P = .05) in the 30-mg group compared with the control group, respectively. Iron supplementation did not affect the prevalence of small-for-gestational age infants or third-trimester iron status. CONCLUSION: Prophylactic iron supplementation that is begun early in pregnancy among low income women in the United States may have benefits beyond the reduction of iron deficiency anemia during pregnancy.

Have we forgotten the significance of postpartum iron deficiency?

The postpartum period is conventionally thought to be the time of lowest iron deficiency risk because iron status is expected to improve dramatically after delivery. Nonetheless, recent studies have reported a high prevalence of postpartum iron deficiency and anemia among ethnically diverse low-income populations in the United States. In light of the recent emergence of this problem in the medical literature, we discuss updated findings on postpartum iron deficiency, including its prevalence, functional consequences, risk factors, and recommended primary and secondary prevention strategies. The productivity and cognitive gains made possible by improving iron nutriture support intervention. We therefore conclude that postpartum iron deficiency warrants greater attention and higher quality care.

Predictors of pregnancy and postpartum haemoglobin concentrations in low-income women.

OBJECTIVE: Pregnancy and postpartum iron status is of great public health importance, yet few studies have examined predictors of haemoglobin (Hb) concentration during this time. We identified predictors of Hb from 24 weeks' gestation until delivery and from 4 to 25 weeks postpartum. DESIGN: Blood was drawn as many as four times during care: at the initial visit, at 24-29 weeks' gestation, at delivery and postpartum. A longitudinal, multivariable linear regression model was used to predict Hb concentration. SETTING: A public health clinic in Raleigh, North Carolina. SUBJECTS: n=520 women who participated in the Iron Supplementation Study. RESULTS: Hb concentration at the previous blood draw, short stature, non-Hispanic white ethnicity/race, >12 years of education and smoking were positive predictors of pregnancy and postpartum Hb concentrations. Iron supplement use was a positive predictor, while inadequate weight gain and severe nausea/vomiting were negative predictors of gestational Hb. A high infant birth weight and postpartum haemorrhage were negative predictors of postpartum Hb. Pre-pregnancy body mass index had a slight positive relationship with gestational Hb, but had a strong negative relationship with postpartum Hb. The longitudinal model also confirmed the typical pattern of gestational Hb concentration. As the number of weeks between the initial visit and the 24- to 29-week visit increased, Hb at 24-29 weeks' gestation decreased. As gestational age increased from 24 weeks until delivery, Hb concentration increased as well. CONCLUSIONS: The predictors identified here could be used in clinical settings to target high-risk women for intervention.

Vitamin C intake and the risk of preterm delivery.

OBJECTIVE: Ascorbic acid deficiency may lead to premature rupture of the membranes. STUDY DESIGN: The study included a prospective cohort of pregnant women, aged >/=16 years, with singleton gestations who received care at one of four prenatal clinics in central North Carolina from 1995 through 1998. Vitamin C intake preconceptionally and during the second trimester was examined for its association with preterm delivery and subsets of preterm labor, premature rupture of the membranes, and medical induction in 2064 women. RESULTS: Women who had total vitamin C intakes of <10th percentile preconceptionally had twice the risk of preterm delivery because of premature rupture of the membranes (relative risk, 2.2; 95% CI, 1.1, 4.5). This risk was attenuated slightly for second-trimester intake (relative risk, 1.7; 95% CI, 0.8, 3.5). The elevated risk of preterm premature rupture of the membranes was greatest for women with a low vitamin C intake during both time periods. CONCLUSION: Because diet and supplement use are modifiable behaviors, corroboration of these findings would suggest a possible intervention strategy.

Who should be screened for postpartum anemia? An evaluation of current recommendations.

The authors evaluated the utility of selective screening criteria for postpartum anemia developed by the Centers for Disease Control and Prevention (CDC) versus criteria developed among low-income women using prevalence-based screening principles. Pregnant women in Raleigh, North Carolina, were followed up to the postpartum visit in 1997-1999 (n = 345). Prevalence of postpartum anemia was 19.1%. Independent risk markers, arrived at through multivariate logistic regression, were multiparity (odds ratio (OR) = 1.5, 95% confidence interval (CI): 0.8, 2.9), obesity (OR = 3.0, 95% CI: 1.6, 5.5), anemia at 24-29 weeks' gestation (OR = 2.3, 95% CI: 1.2, 4.4), anemia before delivery (OR = 3.4, 95% CI: 1.8, 6.7), and not exclusively breastfeeding (OR = 2.8, 95% CI: 1.0, 7.7). Risk scores were calculated by counting risk markers present. Likelihood ratios were determined for all possible risk scores of our algorithm and CDC's algorithm. Anemia screening decisions differed depending on clinic anemia prevalence. For example, if low test thresholds are assumed, when clinic prevalence is 10%, women with risk scores >3 on the authors' algorithm and >0 on CDC's algorithm should be screened. The authors' algorithm, in combination with prevalence information, can save clinics more money than CDC's current algorithm because a broader range of likelihood ratios was obtained, indicating a better ability to distinguish high- from low-risk women. However, if resources are available, universal screening should be considered in high-prevalence settings.