Published Studies/Guidelines: On prenatal/postnatal multivitamins

Abstract
Objective: To provide information regarding the use of folic acid in combination with a multivitamin supplement for the prevention of neural tube defects and other congenital anomalies, so that physicians, midwives, nurses, and other health care workers can assist in the education of women in the pre-conception phase of their health care.
Option: Supplementation with folic acid and vitamins is problematic, since 50% of pregnancies are unplanned, and women’s health status may not be optimal when they conceive.

Outcomes: Folic acid in combination with a multivitamin supplement has been associated with a decrease in specific birth defects.

Motherisk conducted a systematic review and meta-analysis to assess the potential protective effect of prenatal multivitamins on several pediatric cancers. Rates of cancers in women supplemented with multivitamins were compared with unsupplemented women using a random effects model. There was an apparent protective effect against leukemia (OR = 0.61, 95% CI = 0.50-0.74), pediatric brain tumors (OR = 0.73, 95% CI = 0.60-0.88) and, neuroblastoma (OR = 053, 95% CI = 0.42-0.68). In conclusion, maternal ingestion of prenatal multivitamins is associated with a decreased risk for pediatric brain tumor, neuroblastoma, and leukemia. Presently, it is not known which constituent(s) among the multivitamins confer this protective effect.

This is the first study attempting to determine whether circadian variation of folate pharmacokinetics exists in humans. In a new preparation of prenatal multivitamins, PregVit, two tablets a day (a.m. and p.m.) are given. Folic acid is separated from iron and zinc and is given in the p.m. tablet to overcome problems due to folic acid interactions with iron or zinc, and frequent presence of nausea and vomiting of pregnancy in the morning.
RESULTS: The mean AUC values for serum folate after administration of PregVit p.m. were 334.5+/-119.6 nM*h and 283.1+/-64.3 nM*h for morning and evening, respectively (P = 0.17). The morning and evening peak serum folate concentrations were also similar (135.3+/-41.7 nM and 130.3+/-14.2 nM, respectively) (P = 0.75). Similarly, the time to peak for the morning arm (1+/-0.5 hour) was similar to evening administration (1+/-0.4 hour).
CONCLUSIONS: There is no evidence of circadian variation in folate pharmacokinetics. Thus, the introduction of folate in PregVit p.m. will not affect its effectiveness as compared to its routine administration in the morning.

Provided as a courtesy from the Canadian Society for Clinical Pharmacology..

The use of folic acid-fortified multivitamin supplements has long been associated with decreasing the risk of neural tube defects. Several studies have also proposed the effectiveness of these supplements in preventing other birth defects; however, such effects have never been systematically examined. This meta-analysis evaluates the protective effect of folic acid-fortified multivitamin supplements on other congenital anomalies.

Provided as a courtesy from the SOGC.

Prenatal micronutrient combinations with high iron content are associated with high rates of gastrointestinal symptoms. This coupled with nausea and vomiting of pregnancy results in women often discontinuing their multivitamins.

A new prescription supplement (PregVit®) that separates iron from calcium in two tablets - morning and evening, has lower elemental iron content (35 mg), but results in similar extent of iron absorption when compared to another supplement containing (60 mg) of elemental iron (Materna®). The objectives of this study were to compare tolerability and compliance with PregVit® vs. a supplement with high iron content (Materna®), in pregnant women.

The publication suggested that supplementation with folic acid at a dose of about 5 mg per day, before pregnancy and during the first trimester, is expected to decrease the risk of a neural-tube defect by an estimated 85 percent.

The study demonstrated that the absorption of iron from a low-iron-containing (LI) supplement that delivered iron separately from calcium was similar to that from a supplement with almost twice the amount of iron (HICA). This was probably due to the exclusion of calcium from the a.m. tablet with LI (PregVit), as well as lower amounts of other inhibitors of iron absorption. Furthermore, iron in the LI (PregVit) supplement had a higher relative bioavailability than iron in the HICA (Materna) supplement.

Provided as a courtesy from the SOGC.