More Chemicals, More Time to Pregnancy

Chemicals PCB 167 and PCB 138 had the strongest impact on conceiving a child

(RxWiki News) Researchers are learning more all the time about how chemicals in the environment affect our bodies. Much research focuses on children and conceiving a child.

A recent study looked at specific types of chemicals individuals might be exposed to. It found that several pollutants are linked to taking longer to get pregnant.

One particular chemical, PCB 167, had the strongest effect in females while PCB 138 had the strongest effect in males in being linked to longer time required before conceiving a child.

"Reduce your animal fat intake."

The study, led by Germain Buck Louis, from the Division of Epidemiology at the Eunice Kennedy Shriver National Institute of Child Health and Human Health, looked at whether couples having difficulty conceiving a child had higher levels of certain pollutants in their bodies.

The researchers followed 501 couples from Michigan and Texas who had decided to stop using contraception and attempt to conceive a child. They were tracked for 12 months or until they became pregnant.

In addition to daily lifestyle journals kept by the couples and menstrual cycle diaries by the women, the couples' blood was tested for the presence of a range of different chemicals.

The chemicals their blood was tested for included nine organochlorine pesticides, one polybrominated biphenyl (PBB), 10 polybrominated diphenyl ethers (PBDEs, used as flame retardants), 36 polychlorinated biphenyls (PCBs) and seven perfluorochemicals (PFCs).

Analysis of the findings were adjusted across individuals to account for their age, weight, geographic location and a handful of blood characteristics.

Then the researchers compared the concentrations of these different chemicals in the couples' blood to how long it took them to conceive a child.

They found several associations between certain chemicals and taking longer to conceive.

For each unit of increase that women had for four different PCBs, her odds of getting pregnant dropped by 18 to 21 percent. The odds of conceiving dropped 17 to 29 percent for men for each unit of increase they had in their blood of seven different PCBs and a chemical that is formed when the pesticide DDT breaks down.

PCBs are chemicals used in electrical equipment as coolants and lubricants, but some of them often show up in water, soil or animals that people eat. One type of PCB is found in a range of household objects, from clothing and furniture to food packaging and non-stick pots and pans.

Because these chemicals are more often found in fatty tissues, one way individuals can reduce their exposure is not to eat the fat in meat and fish or to eat less meat and fish overall.

One significant limitation of the study was that the researchers did not study all possible chemicals in the couples' bodies, so it is possible the delays in getting pregnant were the result of interactions with other chemicals that were not included in this study.

The study was published November 14 in the open access journal Environmental Health Perspectives. The research was funded by the Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development. The authors declared no conflicts of interest.

Review Date: 
November 19, 2012