It is known well that women are more likely to give birth to twins if their families already have fraternal, or non-identical, twins, and there’s been endless speculation as to why this was the case. Fraternal twin births are on the rise in the western world. In the USA, from 1980 to 2011, the numbers of fraternal twin births have increased by 76% in comparison to non-twin births. IVF is also far more likely to result in twins than conception from sexual intercourse.
A multinational team led by molecular geneticist Hamdi Mbarek managed to compile data from almost two thousand mothers of fraternal twins from the Netherlands, Australia and the USA, and then compared it against women who didn’t have twins or only had identical twins. Scientists alongside him searched for DNA bases which occurred in the fraternal twins’ mothers. After this, they ran a complete analysis again in a database from Iceland. In this manner, they have been able to isolate two genes that increase the chances of having twins, and this was published in the American Journal of Human Genetics in late April.
“IVF is also far more likely to result in twins than conception from sexual intercourse”
The first gene, FSHB, is a gene which increases production of the follicle-stimulating hormone FSH, which causes multiple eggs to be released when the level of FSH is too high. Naturally, this would cause a higher likelihood of twins – more eggs, more chances of multiple eggs being fertilised. It’s just maths, really.
The other one, however, is more complex. The gene SMAD3 changes how molecules signal to each other. In this manner, SMAD3 changes how the ovaries respond to the production of FSH. After being tested in mice, it has clarified only this, and precisely what it does is still an unknown, but Mbarek argues that this could be why some women respond better to IVF treatment than others. Mbarek’s next plan is to study whether women who have the SMAD3 gene are more likely to conceive from IVF treatment.
The results of having just one of these genes in your DNA database is immediately noticeable – having one copy of each of these increases the chances of having fraternal twins by 29%. This find is extraordinary, and with increases of fraternal twins, could indicate these genes are on the rise now that resources are more readily accessible.
As scientific developments and breakthroughs become more innovative and efficient, they also seem to be becoming stranger. Artificial “eggs” are being developed by scientists which could be used as a new contraceptive for women.
However, this is a highly different contraceptive method to the currently widely used pill – these tiny, microscopic “eggs” are made out of seaweed! To put the incredibly small size of the beads into perspective, scientists claim that about eight million would fit on a small fingernail. Made from a substance extracted from the seaweed, this new bio-technology is officially known as ZP2 peptide beads that have the ability to trap the sperm and consequently, prevent pregnancy. This works once the beads are inserted into the woman’s womb where they trap the sperm before reaching the natural eggs creating a highly efficient barrier to the human sperm. A trial carried out by researchers using a sample of mice found that none of them became pregnant once the beads were inserted into their wombs, despite regular mating patterns. As a result, this trial certainly indicates a promising effectivity in the contraception method.
Also, not only do the beads have the possibility to be used for contraception, they also have been found to aid in conception too. For example, a representative from the University of Sheffield Fertility commented on how fertility clinics may be able to develop on the idea that binding the beads can assist in being able to select sperm for use in assisted conception techniques such as IVF. This information is of vital importance due to the current limited ability to select the desired sperm characteristics.
“They trap the sperm before reaching the natural eggs creating a highly efficient barrier to the human sperm”
The future market for this hormone-free alternative in women’s health and family planning appears to be due to the increasingly negative press the contraceptive pill is receiving which tends to be focused around the unwanted and sometimes serious side effects caused by the combined pill. Headaches, nausea, breast tenderness, mood swings and a drop in libido are all commonly experienced symptoms felt by women as a direct result of the pill but it has also been linked to an increased risk of some serious health conditions, such as thrombosis (blood clots) and breast cancer.
Therefore, it isn’t hard to see why scientists are turning to other alternatives for contraception. These seemingly strange seaweed “eggs” may be a new cutting edge hormone-free method in preventing pregnancies around the world at some point in the future.