The Pill doesn't make women fat

Review confirms what (most) docs knew.
Will weight-conscious patients buy it?

By Gillian Woodford

The review looked at 41 studies on OCs, three of which were placebo-controlled. The reviewers couldn't find any convincing evidence that the Pill caused women to pack on extra pounds. "We can't discount that there could be a relation," said author Dr Laureen Lopez, PhD, "but we didn't find any evidence in the studies we looked at."

Thirty-two percent of sexually active Canadian women use OCs as their method of birth control, according to the SOGC's Canadian Contraception Consensus. The Consensus is unequivocal about the OC-fat link: it doesn't exist. Yet 60% of women cite weight gain as a side effect. And while the conclusions of the review won't be news to many MDs, there's clearly a contingent that still subscribe to the belief.

PERPETUATING THE PILL MYTH
There have been theories about the hormones in the combined Pill (which contains both estrogen and progestin) causing fat increase, but the belief seems largely to be perpetuated by word of mouth. OC advertisers often boast their Pill won't cause weight gain, reinforcing the idea the link exists. And the anecdotal evidence is convincing.

Take Sarah C, 25, from Edmonton: "I was on Tricyclen, and when I stopped I lost 10-15lbs in three months. I went back on it and gained it all back, plus more. So I went to my gynecologist, who switched me to Alesse. She said the Pill would make me gain weight in my hips and breasts — she explained it's like your body is preparing to have a baby."

Then there's Lisa L, 27, from Corner Brook, NL: "I was on Triquilar. I went off it for a while then went back on. Later, my gynecologist asked me if I'd gained any weight. I said 'yeah' so he switched me to Tricyclen. I ended up losing about 10 lbs."

It's not surprising so many docs believe there's a link. "Physicians are hearing patients talk about their 'fat clothes' and saying 'I gained weight since I went on the Pill,'" says Dr Robert Reid, a gynecologist and professor at Queen's. "They think, 'I should warn other patients about this.'" A 2004 study led by Dr Reid (included in the Cochrane review) found that women who were counselled by their doctor about weight gain and the Pill were more likely to believe it than women who weren't. "I'm hopeful this [review] will put the issue to rest," says Dr Reid.

UNEARTHING THE REAL CULPRIT
So are women imagining the weight gain? Probably not, but that doesn't mean the Pill's to blame.

"Teens are the largest group of new Pill users and they're also the group most concerned about weight gain," says Dr Reid. And the thing about teens is that they haven't stopped growing. "Women between 13 and 20 will put on weight — it's part of their sexual maturation," he adds. "It's normal physiology," agrees Dr Amanda Black, a gynecologist at the Ottawa Hospital and an author of the SOGC Consensus.

What about women who aren't teenagers anymore? Sometimes they've simply put on a few pounds. "Unfortunately women, well actually everyone, gains weight over the course of their lifetime," says Dr Black. Dr Lopez agrees, adding, "Many people underestimate how much they eat."

Another culprit is water retention. A 1998 study in Contraception (also in the review) bears this out. Women on the Pill were asked to weigh themselves daily for four cycles. Many gained or lost weight but almost all were back to their start weight by the end of each cycle. Dr Reid points out that some newer OCs, like Yasmin, have "a wee bit of diuretic, so this may improve compliance by easing the perception."

So what do you do when confronted by a patient who's convinced the Pill's making her fat? Dr Lopez suggests seeing it as a 'teachable moment'. "This is a good chance to at least get women and doctors to start looking at weight gain," she says. "Otherwise the fear is they'll go off a very effective means of contraceptive."

Dr Black emphasizes a case-by-case approach. "You always have individuals in your office and you have to tailor treatment to them. Maybe that wasn't a good pill for them for a lot of reasons, so maybe you want to try another one."