Deficiency of Zinc Before Conception Triggers Pregnancy Problems

A study ties deficiency of zinc before conception to fertility and pregnancy problems.

Researchers at Penn State's College of Agricultural Sciences conducted a study on mice and found that deficiency of dietary zinc before conception led to pregnancy problems and these mice had smaller and less developed fetuses.

Deficiency of zinc before ovulation not only increases the risk of pregnancy loss but also the embryos in these mice were nearly 38 percent smaller than those from the control group.  Apart from this, nearly half of the embryos had a delayed development due to lack of sufficient zinc levels.

One of the major causes of delayed fetal development is defects in placenta as the developing fetus does not get sufficient nutrients to support normal growth. 

In the six-month study conducted on female mice, the researchers gave them a controlled diet or a zinc deficient diet for 4-5 days prior to ovulation. After this, the researchers evaluated the placental development on the third day, sixth day, 10th , 12th and 16th day of pregnancy. At each interval the researchers evaluated the fetuses. Examination was done using light microscopy and magnetic resonance imaging. 

"What these results demonstrate is that a relatively short dietary disruption in nutrients that are available can have an impact on the ovary, the quality of the egg that the ovary produces, and the quality of the embryo and placenta that the egg develops into after fertilization," said Francisco Diaz, assistant professor of reproductive biology. "We know that dietary restrictions can have an effect on pregnancy and on fetal and placental development, but we are not as familiar with preconception effects that are relatively acute and then seeing the effect later on in pregnancy. That is the most novel aspect of our work here."

The study experts believe that zinc might negatively affect the development of eggs by boosting the epigenetic programming of the DNA of oocytes or immature egg cells. During egg development the methyl groups added at particular sites on the DNA are needed for the egg to support the development of both embryo and placenta.

"It looks like zinc is similar to folic acid, which is one of the few nutrients that are prescribed before a woman becomes pregnant, because it is needed preconception to ensure the quality of the egg,"  Diaz, said. " Zinc is very similar in that it is needed before conception -- so giving multivitamins or supplements to a woman after she has found out that she's pregnant doesn't really address the issue. It is certainly important during pregnancy, but if the egg development is already compromised, it may not help that aspect of development. I think our work suggests that you need zinc preconception, just like you need folic acid."

The finding was documented in Biology of Reproduction.