Avoiding medications, especially antibiotics, when pregnant, appear to be the safest. In a study, researchers found that some antibiotics a pregnant woman takes can affect the unborn baby in several ways. They found a surprising link between these certain antibiotics with birth defects.
Several common types of antibiotics were linked both to birth defects and to organ-specific malformations in infants when taken during the first trimester of pregnancy.
The first large analysis of antibiotics use in pregnancy, for instance, found that mothers of babies with birth defects were more likely than mothers with healthy babies to report taking two types of antibiotics during pregnancy. These were sulfa and urinary germicides called nitrofurantoins.
Birth defects linked to sulfa drugs included rare brain and heart problems, and shortened limbs. Those linked to nitrofurantoins included heart problems and cleft palate. The drugs seemed to double or triple the risk, depending on the defect.
Modern medicine is incredibly conscious of what can harm a new baby, but nothing can be done if the doctor does not know about the disease, or the mother’s symptoms until it’s too late.
In 1979, Food and Drug Administration (FDA) developed a system that determines the teratogenic risk of drugs by considering the quality of data from animal and human studies. FDA classifies various drugs used in pregnancy into five categories, categories A, B, C, D and X.
Category A is considered the safest category and category X is absolutely contraindicated in pregnancy. But no antibiotics get the highest grade of “A.”
The concern about medication use during pregnancy and breast feeding has been influenced by historical events, including thalidomide crisis of the 1960’s.
These events led the US FDA to establish strict regulations regarding drug labelling, the use of medications in pregnancy, requiring demonstrations of safety and efficacy of any drug before it becomes commercially available.
The study, appearing in the 2009 Archives of Paediatrics and Adolescent Medicine, looked at drugs that have been used for decades without large studies of their safety in pregnant women.
The researchers analysed data from more than 13,000 mothers whose infants had birth defects and nearly 5,000 women who lived in the same regions with healthy babies. It was part of the National Birth Defects Prevention Study.
They looked at the use of six different classes of antibiotics. About 30 per cent of the women in each group had used an antibiotic at some point in her pregnancy, or during the previous three months.
But, “there are antibiotics, as there are some other classes of drugs that cannot be used in pregnancy because they have been shown to cause abnormalities. As with all drugs, they should be prescribed and all drugs should be used with caution in pregnancy,” said Dr Adenike Bello, an obstetrician and gynaecologist at the University College Hospital (UCH), Ibadan, Oyo State.
Although the doctor needs to access the drug, the condition and decide whether the benefit of treating it outweighs the risk of getting an abnormality, she said that “the general blanket is that drugs are not safe in pregnancy, and each drug is taken at the face of its own value.”
Even though many women assume that the first three months of pregnancy is the most critical period to avoid medications, she said that is not quite true
Dr Bello stated “The first three months of pregnancy is when the organs are being formed, so the defects that you can have can be absolute. Sometimes, it can be absolute enough that it causes a miscarriage; but there are some that will affect all the way.
“Tetracycline, for instance, at no time in pregnancy is safe because what it affects is the enamel, the lining of the bone and the teeth. So at any time in pregnancy that you use it, this can still cause an enamel malformation in that baby. And a baby born with a bone deformity or teeth deformity has been put at a poor start from the beginning.”
How a drug affects the unborn child depends on the new baby’s stage of development and the strength and dose of the drug. The effect of a medication also depends on the dose that reaches the unborn child as well as exposure to other drugs, chemicals or environmental hazards.
The drug can affect the unborn child in several ways. They can act directly on the baby causing damage or abnormal development leading to birth defects or death.
They can also alter the function of the placenta usually by constricting blood vessels and reducing the blood supply of oxygen and nutrients to the growing baby from the mother and so resulting in a baby that is underweight and underdeveloped.
Moreover, they can cause the muscles of the womb to contract forcefully; indirectly injuring the baby in the womb by reducing the blood supply or triggering pre-term labour and delivery.
While avoiding medications when pregnant may be desirable, some drugs like vitamins, minerals, iron and dietary supplements are essential for the health of pregnant woman and the unborn baby.
Moreover, she declared, “even pregnant women are not immune from falling sick so they should ensure they get antenatal care. There should not be self-medication in pregnancy.”
Meanwhile, when used in early pregnancy, many classes of common antibiotics have also been associated with an increased risk of miscarriage.
In 2013, Danish researchers reported a connection between the antibiotic clarithromycin and miscarriage. They looked at data from the medical records of women aged from 15 to 45 years in the Quebec Pregnancy Cohort between 1998 and 2009.
The study published in the Canadian Medical Association Journal looked at antibiotics exposure during early pregnancy only.
Generally, when a woman does not take antibiotics during pregnancy, her risk of a miscarriage is approximately six to seven per cent. In the study, women who took certain antibiotics in early pregnancy had an increased risk of nine to 10 per cent.
The women who miscarried were more likely to be older, to be living alone and to have multiple health issues and infections, all of which were taken into account when calculating the increased risk for women taking antibiotics.