A potential reason for the increased risk of birth defects associated with pregnancies achieved through assisted reproductive technology (ART) has been found.
An Australian study revealed that in vitro fertilisation (IVF) and intracytoplasmic sperm injection (ICSI) pregnancies had higher exposure to category D medications that could potentially harm the fetus.
Category D medications are drugs that have caused, are suspected to have caused, or may be expected to cause an increased prevalence of fetal malformations or irreversible damage.
“Although ART pregnancies are carefully planned, medications taken during fertility treatments may inadvertently increase exposure to birth defect risks, particularly during critical periods of fetal development,” Hart said.
Yet, the clinical benefit of category D medications in individual cases such as mental health and addiction management, miscarriage prevention, and epilepsy may outweigh the associated risk.
Study leader and researcher Anna Kemp-Casey told The Epoch Times that it is important to weigh up the benefits and risks of any medicines for everyone individually.
What Happened In the Study
Researchers from the University of South Australia, the University of Western Australia, and the Kids Research Institute Australia analysed over 57,000 pregnancies across a two-year period.The study considered four conception groups: women using ART, women taking medication to induce ovulation, untreated sub-fertile women, and naturally fertile pregnancies.
Of the pregnancies analysed, there were 2,041 women using ART, 590 taking medication to induce ovulation, 2,063 untreated sub-fertile women, and 52,987 naturally fertile pregnancies.
The study found that 0.6 percent of the naturally conceived pregnancies and 4.9 percent of the ART pregnancies were exposed to category D medications.
“Category D medicines can cause harm later into pregnancy, but the first trimester is considered the most sensitive period as that is when the most critical fetal development is happening,” Kemp said.
The health records analysed didn’t include those from the birth defects register, so the category D medicines used were not directly found to cause birth defects.
Miscarriage Prevention
The observed differences in exposure were primarily linked to medications preventing repeat miscarriages or failed implantation rather than medications treating underlying conditions.Medroxyprogesterone acetate, which may have been used to prevent threatened or recurrent miscarriages, was the most commonly used category D medicine in this study.
Kemp said previous research has found that medroxyprogesterone can increase the risk of genital defects in girls and abnormal urethra location in boys.
However, currently there are no less harmful medications or methods to prevent miscarriages and failed implantation.
“For many couples, the benefits of avoiding miscarriage and failed implantation will outweigh the risk of a birth defect,” Kemp said.
Mental Health, Epilepsy and Addiction Treatments
Other frequently used category D medications were paroxetine, lamotrigine, valproic acid, carbamazepine and nicotine dependence treatments.Paroxetine is used to treat several mental health disorders, while lamotrigine, valproic acid, and carbamazepine can be used to manage and treat epilepsy and bipolar disorder.
Kemp said there are many other medicines for depression and anxiety that are safer for pregnancy than paroxetine.
However, some women may have a better response to paroxetine than alternative treatments.
Kemp said that for those women, the risks of not continuing paroxetine treatment might be greater than if they continued treatment.
“Epilepsy is more difficult as many of the effective epilepsy treatments are category D,” she said.
“Again, it’s a matter of weighing up the benefits and risks of treatment, because having uncontrolled seizures during pregnancy is also dangerous.”
Nicotine is also a category D medicine, but nicotine replacement is an overwhelmingly safer option than cigarettes.
“If women find that they are not able to stop smoking without using nicotine replacement, they should be reassured that nicotine replacement is their safest option,” Kemp said.
Researchers said the findings underscore the importance of personalised medical care for women undergoing ART treatment and close monitoring for women in early pregnancy.
Hart said more research was needed to examine exposure to category D medications during pregnancy and underlying maternal medical conditions and their contribution to birth defect risk in ART babies.