On-time delivery with vitamin C

It is a well-known fact that pregnant women should take folic acid from the time they start trying to conceive in order to avoid having a child with neural tube defects. Now it seems as though vitamin C is important to pregnant women in antoher area: It protects against premature delivery.
This is the conclusion of a study carried out at the National Institute of Perinatology (the study of diseases in the foetus towards the end of pregnancy and in the baby's first week after birth) in Mexico City.
110 healthy, pregnant women with an average age of 27 participated in the study which lasted from the middle of pregnancy (week 20) until birth. It was a randomized trial in which every other woman was given a daily supplement of 100 mg. of vitamin C while the rest would have to do with the vitamins they got through the diet.
The Mexican women had no greater love for fruit and vegetables than British women. They got an average daily dietary 65 mg. of vitamin C which corresponds fairly well with British conditions. However, half of them got a larger supplement than the recommended daily allowance (RDA) of 60 - 70 mg. which is the content of a typical vitamin pill in this country.
The women were examined every four weeks up until delivery. The primary purpose of the study was to investigate if vitamin C had a protective effect against the bag of water rupturing prematurely. The standard definition stating that if the water breaks more than two hours before the first labour pains, it has broken too early, was used to decide the matter.
In an ideal birth, the water does not break until the external orifice of the uterus is fully dilated and the woman can start to push - this is the meaning of on-time rupture of the bag of water. If the water breaks while the external orifice of the uterus is dilating it is categorized as early rupturing of the bag of water. In both cases, the labour pains occur before the water breaks - this is what happens most frequently and is most practical.
Premature rupture of the bag of water, meaning that the water breaks before the labour has started, is problematic; particularly if it takes a long time for the labour to start. The longer the interval between the water breaking and the labour pains beginning, the greater is the risk of infection in the mother and - particularly - the baby as a result of intrusive bacteria. For this reason, the aim is to have the birth completed within 24 hours after the water breaks. It is very convenient, therefore, that the rupture of the bag of water most often naturally induces labour even though the result may sometimes be a premature birth.
The 100 mg. of vitamin C that 50% of the women in the study were given were not dispensable. No less than every fourth (24.5%) of the women who did not take a supplement experienced premature water breaking while the same thing was the case in only 8% of the women who did take a supplement.
How might this be explained? The authors refer to the well-known effect of vitamin C in the formation of fibres of connective tissue - collagen. Collagen is the most widely distributed protein in our bodies and it is crucial for the strength of our supportive tissues.
The Mexican study indicates that vitamin C is also crucial for the strength of the foetal membranes and thereby for the normal labour process. It can also be put like this: Vitamin C makes sure that it is not weak foetal membranes that determine the time of birth but rather the development of the child. Premature rupture of the bag of water is estimated to be the cause of 40% of all premature births.
In total, the women who were given supplements had an average daily intake of 165 mg. of vitamin C. Whether this dose is optimal is difficult to determine. One thing is certain, however, and that is that regardless of vitamin pills, many pregnant British women get significantly less vitamin C than the lucky half of the women in Mexico City.
References:
Casanueva E, Ripoll C, Tolentino M, Morales RM, Pfeffer F, Vilchis P, Vadillo-Ortega F Vitamin C supplementation to prevent premature rupture of the chorioamniotic membranes: a randomized trial. Am J Clin Nutr. 2005 Apr;81(4):859-63.