More than two million babies are bom each year to mothers who were initially surprised by their pregnancy. Before these women realized they were pregnant, they may have consumed a lot of alcohol or coffee, taken prescription or over-the-counter medications, had X rays or continued using contraception actions they might not have chosen if they’d known that they were pregnant. If you’re caught off guard by a pregnancy, how likely is it that your lifestyle choices could have already harmed your baby?
The fetus is most vulnerable early in pregnancy. Obstetricians describe the time from conception to day 14 of fetal development before a woman has even missed a menstrual period as an “all or nothing” period: If there is severe damage to the cells in this early stage of pregnancy, the woman will miscarry. If the pregnancy continues, the fetus is unlikely to have been harmed. From that point to day 56, the developing fetus is most sensitive to environmental hazards, or substances the mother is exposed to. This is the period of cell organization, cell differentiation and organ formation, and an injury to the fetus during these delicate developments could result in a birth defect.
But doctors cannot be exact about the risks of exposure. Variables such as how much of a substance was consumed, whether it was consumed all at one time or over a period of time, how early in the pregnancy exposure occurred, the mother’s weight and metabolism and even the fetus’s metabolism all make it difficult to gauge potential hazards.
Fortunately, the majority of risks to which pregnant women are exposed are minimal. “We get approximately 7,000 phone calls a year, and the majority are not worrisome,” says Marcia Feldkamp of the Utah Pregnancy RiskLine in Salt Lake City, which fields calls from pregnant women and their doctors who are concerned about exposure to possibly toxic substances. Following are the exposures women generally needn’t worry about, and those that should be of concern.
BIRTH CONTROL When a pregnancy occurs because contraception has failed, it is usually several weeks before a woman realizes she is pregnant. During those weeks she may continue to use and the fetus may be exposed to birth control pills or spermicides that are squirted into diaphragms or used as lubricants for some condoms. (There have been too few pregnancies resulting from Norplant or Depo-Provera failures to have data on those drugs’ effects on a fetus.)
Chemicals in spermicides seem to pose little risk. In the 1980s preliminary research suggested a connection between birth defects, including Down’s syndrome, and exposure to spermicides, but further research did not bear out the link. A study of 13,000 women conducted by the Columbia Presbyterian Medical Center in New York City found no association between spermicide use and Down’s syndrome. Most physicians do not think a fetus exposed to spermicides is at any increased risk.
The hormones in birth control pills don’t seem to pose a major risk either. “The warnings on the labels of birth control pills are pretty dire, but the actual incidence of birth defects is very low,” says Kathleen 0‘Banion, M.D.. an ob-gyn at Jefferson hospital at Thomas Jefferson University in Philadelphia. She has personally delivered healthy babies who had been exposed to birth control pills for several months before their mothers realized they were pregnant.
No firm evidence has been found to establish a relationship between oral contraceptives and an increased risk of birth defects. Nonetheless, once a woman knows she is pregnant, she should promptly stop taking the Pill. Then, Dr. O’Banion says, depending on the type of oral contraceptives and the length of
By Beth Weinhouse time she took it after conception, it may be prudent for the woman to have an ultrasound at between 16 and 20 weeks to confirm normal anatomy.
Intrauterine devices (IUDs) pose more of a problem and may increase the risk of miscarriage or ectopic pregnancy (a pregnancy in which the embryo grows outside the uterus, usually in a fallopian tube). Becoming pregnant while using an IUD is extremely rare, but any woman in that situation should contact a physician immediately. If it’s an ectopic pregnancy, “it’s a potential medical emergency,” says Benjamin P. Sachs, M.D., chief of obstetrics and gynecology at Beth Israel Hospital in Boston. The danger: rupture of the fallopian tube, which can cause serious internal bleeding.
To protect the mother’s health, an ectopic pregnancy is usually terminated with drugs or surgery. But even if the embryo is in the uterus, the woman and her doctor still have to decide whether or not to remove the IUD. Many physicians urge removal because there is a risk of infection or spontaneous abortion if the IUD is left in the womb. If, however, the IUD is not in its proper place, it may be difficult to remove and the physician may advise leaving it in so as not to increase the risk of miscarriage.
MEDICATIONS Only a handful of drugs have been specifically approved for use during pregnancy, chiefly because researchers have considered it unethical to test the safety of medications on pregnant women, except in cases where the drugs were necessary to save the mother’s or baby’s life. Despite the fact that so little information exists on how medications affect the developing fetus, an estimated 75 percent of women use between three and ten prescription and over-the-counter drugs mostly painkillers, antacids and cold and cough medicines during pregnancy.
Some of these common medications are considered safe because so many pregnant women have used them without apparent problems. Doctors are unsure about others. Aspirin, for instance, is considered risky because it may cause bleeding problems. Even so, a couple of aspirin early in a pregnancy are unlikely to cause harm. While women are advised against using decongestant drugs for colds and allergies during pregnancy because they can decrease blood flow to the uterus, if a woman has used one of these drugs a few times early in pregnancy, there’s no cause for panic.
Women taking antibiotics need to discuss their medication with a physician after they discover they are pregnant. While most of these drugs appear to be safe, a few may pose a risk. Tetracycline, for example, may cause a permanent yellowing of baby teeth (although usually only if taken after the twentieth week of pregnancy). Streptomycin has been associated with hearing impairment in infants exposed during pregnancy.
One of the riskiest medications is the drug Accutane, a prescription drug derived from vitamin A that’s used to treat severe cystic acne. Accutane is rarely given to reproductive-age women because it is considered such a potent teratogen (a substance that causes birth defects). Women who take the medication are urged to use a reliable method of birth control and even to take frequent pregnancy tests. Any woman who discovers she is pregnant while using this drug should stop taking it immediately and see her doctor to discuss what the risks and options are.
Vitamin A itself can also be a pregnancy hazard. “Megadoses of vitamin A can cause quite severe birth defects,” explains Dr. Sachs. Medical case reports have found fetal abnormalities with daily doses of 25,000 IU or more but little risk at doses of 10,000 IU or less (the recommended daily allowance for vitamin A is approximately 2,700 IU per day, and most daily vitamins contain 5,000 IU).No tags for this post.