The pill could lower sex drive in young women

The pillThis month marks the 50th anniversary of the contraceptive pill, first approved by the FDA in 1960 and now the choice of contraception for more than 100 million women worldwide. By uncoupling sex from pregnancy, oral hormonal contraceptives finally allowed women to become agents of their own bodies.

Life isn’t all rosy on the pill though. The various different formulations have been associated with all sorts of side effects, the most issue being venous thromboembolism.

Now new research from female medical students in Germany has found that hormonal contraception such as the pill could also reduce sex drive.

Several previous studies have suggested that oral contraception might affect female sexual function, but overall the evidence as to whether they have a positive or negative effect is pretty mixed.

The researchers behind this study emailed female students at six medical schools in Germany and asked them to fill in an online questionnaire about their sexual function in the past four weeks and their usual means of contraception over the past six months.  A total of 1,086 women (15-20%) aged mostly under 25 years responded.

A total of 87.4% of women had used contraception in the previous 6 months, most of whom had used oral hormonal contraception (69.5%).

About a third (32.4%) of participants were considered at high risk of sexual dysfunction.  However, this figure actually isn’t too bad compared with a previous study of 78 female medical students in the US, which found that 63% were at high risk of sexual dysfunction.  Other larger studies put the rate at a more conservative 38% in Germany and 43% in the States.

When the sexual dysfunction data were analysed on the basis of single usual form of contraception (1,046 participants), women who used oral hormonal contraception or non-oral hormonal contraception were most at risk of having sexual dysfunction. Oral hormonal contraception was associated in particular with low desire and arousal compared with other forms of contraception and no contraception.

The authors suggest that the link between oral hormonal contraceptives and sexual dysfunction may be because oral contraceptives decrease the circulating levels of testosterone, “which is needed to (i) stimulate sexual desire and (ii) regulate genital blood flow and the structural and functional integrity of the genitals.”

Interestingly, smoking was associated with a lower risk of sexual dysfunction than not smoking, an effect the authors hilariously suggest might be down to the fact that “smokers might have greater ability to enjoy themselves.”

“This is a very important research investigation,” stated Dr Irwin Goldstein, Editor-in-Chief of Journal of Sexual Medicine, which published this study. “There are hundreds of millions of women, in particular young women at the beginning of their sexual lives, who regularly use hormonal contraception for many years. The irony is that these women are provided a medication that enables freedom from reproductive worries but these same women are not provided information that there are significant adverse sexual effects that may ensue.  Agents that interfere with the hormonal milieu of women may adversely affect their sexual lives.”

Don’t panic yet though, this study isn’t the final word and has various shortcomings, not least the possibly of participation bias – where women with perceived sexual problems might have felt more inclined to participate than women with no sexual problems – and reporting bias – where participants might have overestimated or underestimated the scale of their sexual difficulties.

Furthermore, the low response rate to the questionnaire (15-20%) means the study population probably isn’t a great reflection of all the female medical students at the eight schools studied, much less students worldwide, and, as the authors say, their stats suggest that “the factors considered can only explain a small fraction of the variability of total [female sexual function] scores.”

As it is, hormonal forms of contraception – both oral and non-oral – are the most successful forms around.  So I wouldn’t throw away your pills just yet.

  • Put off oral hormonal contraceptives? Nature Medicine has an article on the 50th anniversary of the pill that highlights some possible alternatives under development.

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Wallwiener C et al. (2010) Prevalence of Sexual Dysfunction and Impact of Contraception in Female German Medical Students. Journal of Sexual Medicine DOI: 10.1111/j.1743-6109.2010.01742.x

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IVF does not increase the risk of complications at birth

I recently read an interesting paper in The Lancet about birth complications in women who conceive using assisted fertilization, i.e. IVF, compared with complications in women who give birth having conceived normally.

Studies generally report a higher risk of complications at birth for babies conceived by IVF than for those conceived naturally. Women who undergo fertility treatment are far more likely to have twins or triplets than are women who conceive naturally thanks to the high number of embryos implanted, so a considerable proportion of the risks associated with IVF are in fact complications relating to multiple births.

However, the risks of complications before, during and after birth are still higher in women who conceive only a single child when undergoing assisted reproduction. For example, a meta-analysis published in the BMJ in 2007 found that singleton babies conceived with assisted reproduction were at least twice as likely to be born prematurely as babies conceived naturally, and one and a half times more likely to be born by cesarean section.

A group in Norway lead by Dr Liv Bente Romundstad has now found that the risk of perinatal complications in singleton births conceived using assisted reproduction is no worse than that of singleton births conceived naturally, suggesting that IVF techniques are more safe than previously thought.

The authors came to this conclusion by assessing 2,500 women who had given birth to at least one child who had been conceived naturally and one who had been conceived using assisted fertilization. Among these siblings, the risk of premature delivery and of small size for gestational age were not significantly higher in those conceived by assisted reproduction than in those conceived naturally. The authors suggest that the poor perinatal outcomes reported in women who conceive using IVF might not be the fault of the assisted reproduction techniques and instead might be attributable to maternal factors, such as underlying infertility.

This study is particularly interesting because researchers investigating outcomes after assisted reproduction find it hard to untangle the possible negative effects of IVF technology from other factors that might adversely affect birth outcomes. The women who use IVF tend to do so because they’re having fertility problems, making them – and their birth outcomes – inherently different to women who conceive naturally.

Romundstad et al. controlled for such maternal factors by comparing IVF and natural conceived births in the same women, rather than births in two completely separate populations,. The births in either group had the same maternal baseline characteristics, so the authors were able discern the effect of IVF.

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