Small for gestational age (SGA) is a term used for babies who are smaller than the expected average size associated with the number of weeks their mother has been pregnant. These babies usually have a birth weight below the 10th percentile for babies of the same gestational age. This means only 10% of babies born at this gestational age are smaller than a typical SGA baby. SGA babies may be born prematurely, full term, or post term— these babies are small due to genetics or fetal growth problems that can occur during pregnancy, not because of premature delivery. Small for gestational age babies are at an increased risk for neonatal morbidity and mortality and face the risk of many chronic diseases later in life such as diabetes, hypertension, obesity, cardiovascular disease and mental health problems.
Folic acid supplementation provides many benefits for a baby including protection from neural tube defects such as spina bifida. Women are suggested to begin supplementation with folic acid even before they have attempted to conceive, yet past studies have shown only 14-31% of women follow this recommendation.
A study in the United Kingdom was done to assess whether the timing of folic acid supplementation during pregnancy effects the risk of having an SGA baby. Of the 108,525 women initially observed, 84.9% took folic acid during pregnancy. Almost 40,000 of these women recorded the time they began supplementation, only 25.5% of them began taking folic acid before conception. Of the women who did not take folic acid at all, 16.3% had SGA babies, while 13.8% of women who began taking folic acid after conception had babies in the tenth percentile. Only 9.9% of women who began supplementation pre-conceptually had SGA babies, with only 4.8% of their babies falling into the fifth percentile.
Not only does this data indicate that folic acid produces a positive effect on birth weight, but it also reveals that folic acid intake recommendations are poorly followed in the United Kingdom. Increased steps must be taken to raise awareness of the benefits of folic acid supplementation when taken before conception, while research must still be done to discover how folic acid produces these beneficial effects.