How He Fits into Baby's Development
As a mother-to-be, you want your partner to help meet your baby's physical, developmental, and emotional needs. His biological contribution is probably the last thing on your mind -- that ended at conception, right? Not necessarily. Growing scientific evidence suggests that Dad's lifestyle has a great impact on the health of his unborn baby. It's long been known that infertility, miscarriage, birth defects, low birth weight, and stillbirth might occur if the mother smoked, drank alcohol, used drugs, took certain medications, or was exposed to toxic chemicals. But we now know that fetal development -- and male infertility -- can be affected by the father's habits and lifestyle too. There's also evidence that a father's behavior can affect how the mother handles pregnancy and manages her stress levels, both of which can affect the health of an unborn baby. Here are some of the risks fathers can contribute and how to deal with them.
Fortunately, the vast majority of men who work with potentially risky chemicals and substances do not father children with birth defects, nor do their partners have a higher-than-normal risk of pregnancy complications. However, a small number of industrial, chemical, and environmental substances may affect the male reproductive system, resulting in low sperm count and infertility, miscarriage, and other problems.
In the 1970s and 1980s, research showed that miscarriage and infertility could result from a father's exposure to vinyl chloride, which is widely used in the electronics industry. Since then, studies have suggested that a man's exposure to metals (such as lead and mercury), to chemicals used in rubber and plastic manufacturing, and to certain industrial solvents before and around the time of conception may also increase the risk of miscarriage. In most cases, these men were more likely to produce abnormal sperm, which resulted in unviable embryos.
Recent studies suggest that some of the most risky chemicals are industrial solvents, such as benzene and ethylene glycol ethers. One study found that men who were exposed on the job to ethylene glycol ethers were more than twice as likely as unexposed men to be infertile. The people likeliest to encounter these solvents include dry cleaners, printers, textile workers, computer-chip factory workers, pesticide sprayers, and anyone who works with paints, varnishes, or paint thinners. Pesticides may also pose other risks. One study suggested that male applicators of particular pesticides may be at increased risk of fathering a child with a birth defect or learning and behavioral disabilities.
That said, expectant fathers and men thinking about fatherhood should take all practical steps to protect themselves (and their future children) from toxins in their workplace. Keep in mind that a person can take these chemicals into the body by breathing them in, ingesting them in food or drink, or absorbing them through the skin. Workers should always wear recommended protective clothing and equipment, such as a mask and gloves. Also, it's vital that anyone who works around these chemicals take their meals outside any chemically contaminated work area.
Men who are exposed to lead, such as painters or those working in smelters, auto repair shops, battery manufacturing plants, or certain types of construction, should do everything they can to avoid bringing lead dust into their home on their clothes and shoes. When a pregnant woman is exposed to high levels of lead, it can contribute to miscarriage, preterm delivery, low birth weight, and developmental delays in the infant. Dad should change and shower at work, and if possible, launder contaminated clothing there. If this isn't possible, he should wash work clothes at home separately from the rest of the family's clothes.
Men who are planning to become fathers have another good reason to quit smoking. Smoking can reduce sperm count, as well as cause serious abnormalities in the shape and movement of sperm, so it may contribute to infertility. Even if you have conceived successfully, a smoking habit can still harm your unborn child. Nonsmoking women whose partners smoke are at increased risk of having a low birth weight baby (less than 5 1/2 pounds) due to the effects of secondhand smoke. Low birth weight babies are at increased risk of health problems during the newborn period and of lasting disabilities; they are also about 20 times more likely to die in their first year of life than normal-weight babies. And once a baby is born, studies suggest that living with a smoker increases his risk of sudden infant death syndrome (SIDS), as well as lower respiratory infections and asthma.
While pregnant women who drink risk having a baby with fetal alcohol syndrome (characterized by mental and physical birth defects), there's no evidence that a father's drinking can cause this problem. However, heavy drinking may reduce a man's sperm count and fertility. It may also affect his relationship with his pregnant partner. As with cigarettes or drugs, if an expectant father brings alcohol into the home, it may make it harder for his partner to avoid these types of habits.
No medication, either prescription or over-the-counter, used by men has been proven to cause birth defects in their children. However, if you want to start a family, it's important to remember that some commonly used medications can affect sperm production, sometimes leading to reduced sperm count or sperm that can't move effectively. Some medications can also reduce a man's sexual desire or ability to function sexually.
If you're trying to conceive and your partner is taking cimetidine (used for ulcers), antidepressants, antibiotics (sulfa drugs, erythromycin, and tetracycline), calcium-channel blockers and propranolol (both used for high blood pressure), or colchicine and allopurinol (used to treat gout), he may need to talk to his doctor about a medication adjustment. A man's fertility should return to normal soon after he stops taking these medications. However, men with cancer who receive chemotherapy often develop permanent or long-term sterility. Men who must undergo chemotherapy should consider the option of storing sperm before they begin treatment. Fortunately, for most future fathers, a few lifestyle changes can make a big difference to their pregnant partner and unborn child.
Richard H. Schwarz, MD, obstetrical consultant to the March of Dimes, is vice chairman for clinical services in Maimonides Medical Center's department of obstetrics and gynecology and a professor of gynecology and obstetrics at SUNY Downstate Medical Center, both in Brooklyn.