If you're having trouble getting pregnant, you're willing to try just about anything to increase your chances of success. A rumor that pops up frequently on fertility forums states that drinking pineapple juice can increase the uterine lining thickness and improve chances of implantation. Not only is this unproven, but the core of the pineapple contains ingredients that are potentially harmful during pregnancy. Drinking pineapple juice will not improve the uterine lining, since it contains no more nutrients beneficial to uterine thickness than any other food.
The core of the pineapple contains bromelain, a mixture of enzymes that digests proteins. Bromelain acts as a blood thinner and may have anti-inflammatory effects. While fertility specialists sometimes give blood thinners such as baby aspirin to help with implantation, the dose is controlled. Bromelain in large doses can cause uterine contractions and interfere with implantation of an embryo, although studies on this effect also are lacking. Some cultures use bromelain to start labor in pregnancy. Pineapple juice contains little or no bromelain, which is concentrated in the pineapple's core. Do not take bromelain supplements unless your doctor recommends it.
Several minerals in pineapple, including selenium, supposedly contribute to improving the uterine lining. A cup of pineapple juice contains just 0.2 micrograms of selenium, a tiny percentage of the 55 micrograms required for adults over age 19. The food highest in selenium, Brazil nuts, contains 544 micrograms per ounce. Before you switch your food allegiance to Brazil nuts to help you get pregnant, consider that more than 400 micrograms of selenium per day can cause selenosis, which can lead to mild nerve damage, fatigue and irritability. Most adults in the United States gets an adequate amount of selenium in their diet; in countries where the soil contains little selenium, deficiencies can develop.
Uterine Lining and Pregnancy
The uterine lining does play a part in pregnancy, even if pineapple juice doesn't improve it. You have your best chance of getting pregnant when the uterine lining reaches not only a certain thickness but also has a certain pattern. The pattern changes during the menstrual cycle; a good pattern in the first half of the cycle, before ovulation, is not a good pattern after ovulation. A trilaminar lining, also called a triple lining or a TL pattern before ovulation is best for conception. Once your body produces progesterone, your lining should change to a homogenous pattern, sometimes called an HH pattern. A lining of between 7 and 12 millimeters is optimal for conception, but people can and do get pregnant with linings as thin as 3 millimeters, Dr. Timothy Hickman of Houston IVF reports on the Fertility Today website.
When trying to get pregnant, it's best not to focus on one aspect to the exclusion of others. An adequate uterine lining is important, but many other factors also contribute to pregnancy. Ingredients in pineapple can have both potentially helpful and harmful effects on pregnancy. No clinical studies have proved that pineapple juice has any benefit on the uterine lining. If pineapple had any benefit, fertility doctors would include it as part of their treatment regimen. Talk with your doctor about ways to improve your uterine lining and about the potential effects of pineapple.