Paternal Exposures


The information provided below is for readers based in the United States of America. Readers outside of the United States of America should seek the information from local sources.

What are paternal exposures?

A paternal exposure is any agent to which the father or your baby may be exposed before conception or during your pregnancy. Such agents may include tobacco, alcohol, and various other drugs, occupational (workplace) exposure to various chemicals or radiation, chemotherapy and radiation therapy for cancer or other diseases, and medications. Infectious agents to which a father is exposed, such as viruses, can also be a problem as they can transfer to the mother, causing problems in the pregnancy and/or for the baby. One such example is Zika virus.

Is there a safe level of exposure to which the father of my baby can be exposed prior to or during my pregnancy?

This depends on the drug, environmental chemical, or other agent in question. When it comes to most medications and chemical agents, paternal exposure is not an issue for your pregnancy. For many agents, such as heavy metals, organic pollutants, and other environmental agents called phenols and phthalates, concern is greatest surrounding the question of whether the agent might make it more difficult for you to become pregnant, rather than whether there will be a problem with the pregnancy or the baby. For other agents, in addition to concerns regarding the ability to get pregnant, there are concerns regarding genetic damage in sperm cells that can lead to the pregnancy ending early (miscarriage) or problems with the baby, namely birth defects.

Can paternal exposure make it harder for me to get pregnant?

For various types of exposure, the answer is yes. For many agents, such as heavy metals, organic pollutants, and other environmental agents called phenols and phthalates, concern is greatest around the question of whether the agent might make it more difficult for you to become pregnant.

Can paternal exposure cause a miscarriage?

Yes, exposure of the father to certain agents before conception has been linked to in increased rate of miscarriage. One such exposure that is well established is the chemical formaldehyde, which is used in various industrial processes. Less certain, but still considered to be very likely, is that paternal exposure to lead and mercury also increases the risk of miscarriage.

Can paternal exposures cause a birth defect?

Yes, there is concern that paternal exposure to certain substances and to ionizing radiation may possibly lead to birth defects, although ionizing radiation more often has a negative effect on a potential father’s fertility. One very clear connection involves exposure to a biological agent, the Zika virus. A man who is infected with Zika virus can transfer the virus to the female partner before, during, or after the time that he impregnates her. Once the mother is infected, there is a higher risk of birth defects, particularly a malformation called microcephaly, featuring a very small head size with the size of the brain significantly reduced.

Are there long-term consequences to my baby from paternal exposures?

As noted earlier in this report, there are agents to which the father can be exposed, such as lead, mercury, and Zika virus, which can have long-term consequences in the form of birth defects. Tobacco smoking also can affect the baby in the long-term, not only when the father smokes in the child’s presence after birth, but also due to the effect of secondhand smoke on the mother. One big example is childhood obesity, which has been linked to paternal smoking, as well as to maternal smoking.

I just found out I am 6 weeks pregnant and last weekend the father was exposed to a substance that may be harmful. Will my baby have a problem?

In almost all cases, the answer is no. As noted above, paternal smoking can affect your baby as you breathe the second hand smoke, but this is an exposure that must take place over a long period of time to cause a problem. Most of the other agents are issues only before conception.

Is paternal binge exposure only some days of the week as risky as exposure to a harmful substance everyday but at lower amounts?

This would depend on what the agent is, and in most cases differences in pregnancy outcome would be difficult to relate to differences in patterns of exposure in the father.

Is it ok for the baby’s father to be exposed to some harmful agents after the first trimester?

In most cases, after conception, exposure of the father does not have an impact, but there are some exceptions. With tobacco smoking, for instance, by exposing you to the smoke this raises the risk of childhood obesity.

Can a baby go through withdrawal from paternal exposure after birth?

No. A baby cannot go through withdrawal from a substance to which the father has been exposed, unless the mother also has been exposed. In the latter case, however, such an exposure would be primarily a maternal exposure, not a paternal exposure.

How will I know if a paternal exposure has hurt my baby?

You would know that there is a connection between a paternal exposure of an agent and the baby being hurt, if the father is the only link between the agent and the harm. In the case of Zika virus for instance, the usual way to be infected is through the bite of a mosquito in particular regions of the world. Thus, if the mother has not traveled to such a region, but the father had been to such a location just prior to conception and then the mother developed a Zika virus infection, harm from the virus, such as microcephaly then could be linked to the father’s infection.

Is there any hope for a baby whose father has been exposed to a harmful agent?

Yes. The case of paternal exposures leading to problems for the baby are actually quite rare, so most of the time the baby will be perfectly fine.

Do paternal exposures have any relevance to breastfeeding?

In certain cases, this is possible. With tobacco smoking for instance, a nursing infant can be exposed to second hand smoke, which can give the infant respiratory problems.

Resources for paternal exposures in pregnancy:

For more information about paternal exposures during pregnancy, contact (800-994-9662 [TDD: 888-220-5446]) or read the following articles:

Mother to Baby: Paternal Exposures and Pregnancy

Mayo Clinic: How does paternal age affect a baby's health?

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General information

It is very common for women to worry about having a miscarriage or giving birth to a child with a birth defect while they are pregnant. Many decisions that women make about their health during pregnancy are made with these concerns in mind.

For many women these concerns are very real. As many as 1 in 5 pregnancies end in a miscarriage, and 1 in 33 babies are born with a birth defect. These rates are considered the background population risk, which means they do not take into consideration anything about the health of the mom, the medications she is taking, or the family history of the mom or the baby’s dad. A number of different things can increase these risks, including taking certain medications during pregnancy.

It is known that most medications, including over-the-counter medications, taken during pregnancy do get passed on to the baby. Fortunately, most medicines are not harmful to the baby and can be safely taken during pregnancy. But there are some that are known to be harmful to a baby’s normal development and growth, especially when they are taken during certain times of the pregnancy. Because of this, it is important to talk with your doctor or midwife about any medications you are taking, ideally before you even try to get pregnant.

If a doctor other than the one caring for your pregnancy recommends that you start a new medicine while you are pregnant, it is important that you let them know you are pregnant.

If you do need to take a new medication while pregnant, it is important to discuss the possible risks the medicine may pose on your pregnancy with your doctor or midwife. They can help you understand the benefits and the risks of taking the medicine.

Ultimately, the decision to start, stop, or change medications during pregnancy is up to you to make, along with input from your doctor or midwife. If you do take medications during pregnancy, be sure to keep track of all the medications you are taking.

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