I had the privilege last week on being asked to talk at the Royal Australian and New Zealand College of Obstetrics and Gynaecology conference in Queenstown. The subject was pregnancy and fertility after bariatric surgery; which is very topical given the numbers of women who undergo bariatric surgery, and the questions they have on their ability to have children. I will summarise the important parts of the talk below, and in the next blog post.
So what effect does weight loss surgery have on women’s fertility?
Firstly, we know that many women suffering from obesity, also suffer from infertility and/or have polycystic ovarian syndrome (PCOS). The reason behind this is that carrying extra weight around the abdomen causes people to become resistant to the hormone insulin. Initially, the pancreas responds to this by producing extra insulin, which among other effects drives the ovaries to produce male hormones, leading to further weight gain, hair growth and reduced fertility.
Weight loss surgery is very effective in helping reverse this cycle. Loss of weight from the middle of the body results in increased insulin sensitivity and improvement of the other hormonal changes. Two studies measuring the outcomes of women with PCOS and infertility show that 70-100% of women with irregular menstrual cycles resume normal menstruation following bariatric surgery. At least 20% of women were able to conceive without the help of additional therapies, and three-quarters of the women with abnormal hair growth had moderate or complete resolution of this.
It is important to realise that bariatric surgery is not recommended as a first line treatment for infertility, but that weight loss after surgery does lead to significant improvements in fertility and may be useful as part of an overall treatment package.
Does weight loss surgery affect birth control?
Given weight loss surgery improves fertility, it is also important to consider the effect on contraception, for women who are not wanting to become pregnant. Oral contraceptives (the pill) are not considered to be reliable after weight loss surgery due to differences in absorption with gastric bypass or vomiting after adjustable gastric banding. The large amount of weight that women lose after surgery may also increase failure rates of contraceptive caps and diaphragms. Contraceptive recommendations for women after bariatric surgery include hormonal methods not taken by mouth (the injection, contraceptive implants, and IUCD’s such as Mirena) and male barrier methods (condoms). For further advice, please talk to your general practitioner or family planning specialist.