Potential issues and risks of Minoxidil in pregnancy
The main concern with Minoxidil use in pregnancy is its systemic absorption, which could potentially affect the developing foetus. And while systemic absorption is most commonly seen with oral Minoxidil, there have been instances of topical Minoxidil causing problems with the baby’s development in utero [6].
Minoxidil’s vasodilatory properties may increase blood flow to the placenta, raising concerns about possible adverse effects on foetal growth and development.
One study reports the case of a 28-year-old woman who applied Minoxidil 2% to her scalp daily due to hair loss. When she had a routine ultrasound scan 22 weeks into her pregnancy, the test showed significant heart, brain and vascular malformations in the baby [6].
The heart had increased in size and had a spherical shape with distal stenosis in the aorta. That means a major artery valve was narrowed, restricting blood flow.
The baby’s colon was also significantly longer than is typical and the ventricles in the brain were also enlarged, with significant bleeding. The placenta also had ischaemic areas and did not appear to have developed correctly considering the baby’s gestational age. There were also signs of the abnormal formation of blood vessels and extensive damage to the nervous system [6].
Aside from this case, rare cases of hypertrichosis (excessive hair growth) have been seen in newborn babies among women who used Minoxidil during pregnancy. This is called foetal Minoxidil syndrome [7] and usually diminishes after six months. Other symptoms of foetal Minoxidil syndrome include problems with heart, brain, and kidney function, as well as limb malformations.
Animal studies have also shown the negative effects of Minoxidil in pregnancy. Studies revealed that there was increased foetal absorption of the drug when it was administered at five times the maximum recommended human dose [8]. There was no concrete evidence of teratogenicity (reproductive toxicity causing foetal abnormalities), however [9].
Current research suggests that it’s not safe to use Minoxidil in pregnancy, so it’s recommended that you avoid applying Minoxidil for hair loss when pregnant. As a precaution, women may also want to consider avoiding Minoxidil when trying to conceive.