The active ingredient of Viagra, sildenafil, has passed the second phase of clinical trials as a means to prevent oxygen starvation in children in childbirth, the American Journal of Obstetrics and Gynecology reported. Sildenafil dilates the blood vessels of the placenta and thereby enhances blood flow to the fetus. This reduces the likelihood that the mother will need to have a cesarean section if her baby begins to experience oxygen deficiency during labor.
Contraction of the uterus during childbirth reduces the intensity of blood flow through the placenta, so if contractions occur very often and last a long time, you often have to do an unplanned cesarean section. Abdominal surgery is always a risk that doctors try to avoid. This can be done in theory if the blood flow in the placenta is somehow restored.
Promising initial results from the Viagra trial
Scientists from the University of Queensland under the leadership of Sailesh Kumar tried to increase the blood supply to the fetus during contractions of sildenafil. It is well known that at first they were going to use it to improve blood flow to the heart, but found that it has a much greater effect on the vessels of the pelvic organs. Ex vivo studies have also shown that the drug dilates the vessels of a normally developed human placenta.
Australian scientists have invited to participate in a study of 300 women whose pregnancy was uneventful and who were preparing to give birth in a hospital in Brisbane. During the fights, half of them were given 1-3 tablets of sildenafil, and half were given a placebo. At the same time, they monitored the fetal heartbeat (irregular contractions could mean a lack of oxygen) and noted in what percentage of cases women in labor would need an unplanned cesarean section.
Among those given sildenafil, the emergency cesarean section was prescribed 51 percent less often (p = 0,0004) and 43 percent fewer cases of irregular cardiac contractions in the fetus were recorded (p = 0,0005). The drug did not have serious side effects on the well-being of women. The concentration of sildenafil in cord blood averaged 3.6 percent of that in the maternal, which means that the use of this medication during labor is unlikely to harm the child.
Research is still ongoing
However, the delayed effect of the drug on the health of women and their children has not yet been fully studied. Moreover, 11 children died after a study of sildenafil in the Netherlands, so Australian scientists suspended their trials for some time. However, the Dutch did not study the effect of the active substance of Viagra on the bloodstream in the placenta during normal pregnancy, but the effects that sildenafil has on unborn children with serious intrauterine growth retardation. The fact that some of the children died during this study does not mean that the drug is dangerous to them, but rather that it does not normalize the development of the fetus.
Now, Sailesh Kumar and his colleagues plan to conduct the third phase of clinical trials of sildenafil as a means of anti-child hypoxia during labor. It is estimated that around 3,000 pregnant women will participate in it.
Sildenafil is a very versatile drug. It is already routinely used to treat pulmonary arterial hypertension. In 2014, doctors tried to use sildenafil as an experimental therapy for lymphangiomas in children (but it didn’t help everyone), and in 2016, when dealing with disorders of lymphatic tissue growth in an adult. Finally, in 2019 in experiments on mice, the active substance of Viagra in combination with AMD3100 facilitated the release of blood stem cells from the bone marrow into peripheral blood, which is sometimes necessary for their collection as donor material.