Phthalates - and why it’s critical to avoid them in pregnancy
A meta-analysis from 2017, which looked at the sperm count of over 40,000 men - who importantly were unselected for fertility issues (so just regular guys from across four countries), showed a 50% reduction in sperm count between 1973 and 2011. This is a marked and concerning decline in male fertility.
So what’s causing this reduction in sperm count? One of the biggest contributing factors that has been proposed is our ever-increasing exposure to phthalates. While infertility is considered to be an adult issue, recent research is pointing to the impact in-utero exposures has on our ability to be fertile later in life. For a foetus to develop as a male, we need enough testosterone present to stimulate the proliferation of sertoli cells. The number of sertoli cells a male has, is a determinant of how much sperm they will make as an adult, and there are three windows in a male life for the growth of these cells - in utero, a short time post-birth, and around puberty. The issue with phthalates is that they have an anti-androgen effect in our body, which lowers the amount of testosterone, and has the effect of reducing the proliferation of the sertoli cells. From rodent studies, it’s been estimated that the in-utero window for the optimal masculinisation of a male fetus is 9-14 weeks gestation, so it’s so important that we reduce our phthalate exposure prior to this.
And it’s not just male fertility issues that phthalates have been linked to, being an “endocrine disruptor”, it’s proposed they are influencing all manner of hormonal systems; miscarriage, gestational diabetes, early onset of puberty in girls, hypospadias (congenital male urethra malformation), and reduced penis width in males. In animal studies, phthalates have been shown to damage the kidneys, liver, lungs & reproductive systems.
Phthalates are a group of chemicals used to make plastics soft and flexible and harder to break. They There are three ways we can be exposed - ingestion, inhalation, and dermal contact. Phthalates are found in all types of cosmetics and make up, fake tan, synthetic fragrances (think perfumes, and anything perfumed such as laundry detergent air freshener, shampoo etc), toys, plastics and plastic food wrap, plastic water bottles, shower curtains, cheap raincoats, take away food containers, medical equipment such as tubing - the list goes on! I’m sure you’re getting the idea how pervasive they are in our lives.
So pregnancy is an incredible window of opportunity to reduce our exposure to phthalates, to improve the long-term outcome for our children. The good news is, phthalates don’t have a very long half life in our body, so reducing our daily level of exposure will have a positive, and immediate, effect. Switch out conventional cosmetics and body care products for natural alternatives, ditch anything you use with a synthetic fragrance, use glass to store food and drink at home.
“Temporal trends in sperm count: a systematic review and meta-regression analysis”