The Duggars, shown here in 2010, just announced they're expecting… (Scott Enlow / TLC )
It will be an even 20 for Michelle and Jim Bob Duggar, who announced Tuesday that they're expecting their 20th child. The Duggars, stars of their own TLC show, are a source of fascination for some people, since super-sized families aren't the norm the way they were about a century ago.
Michelle Duggar, you'll recall, didn't have such an easy time around with her last pregnancy in 2009. Daughter Josie was delivered early when it was discovered that Michelle had preeclampsia and gall bladder problems (Josie is now doing fine). Preeclampsia usually occurs later on in pregnancy and is characterized by high blood pressure and high protein levels in the urine. It can cause serious complications for the mother (stroke, seizure) and baby (insufficient blood flow to the placenta).
Even if Michelle has a trouble-free pregnancy, there are certain health risks--and benefits--linked with large families. One 2007 study in PLoS Medicine found an association between being a younger member of a large family and having a greater risk of stomach cancer.
Researchers looked at data on more than 9,935 Japanese American men who were followed for 28 years. They discovered that men who carried specific H. pylori bacteria strains and came from families with seven-plus siblings were more than twice as likely to get stomach cancer than men who also had the bacteria and had up to three siblings. Younger siblings may be more vulnerable, the authors said, because their immune systems may be weaker when they're exposed to the bacteria from their siblings.
A 2008 study in the journal Respiratory Research found that coming from a large family may be a risk factor for snoring in adulthood. After surveying 15,556 people, scientists discovered several health factors that may be related to snoring, including having recurring ear infections and being hospitalized for a respiratory infection in childhood, as well as being from a large family. Increased inflammation that could change the anatomy of the upper airway early on could make them more prone to snoring later in life, the authors said.
Parents with larger families may be at a higher risk of early death. A 2006 study in the Proceedings of the National Academy of Sciences looked at reproduction and survival among 21,684 couples who were married between 1860 and 1895 in Utah. Having a larger amount of children was linked with a greater risk of early death for both mothers and fathers.
"These kinds of fertility patterns and survival patterns are still present today in developing countries," lead author Ken Smith told the Deseret News in 2006. "It's not like these stresses and costs associated with having children have disappeared from the planet because it's the 21st century."
Not all the news is bad--a 2011 study in the journal BMC Cancer found that although larger family size was linked with a greater risk of developing lungand stomach cancer and cancer of the nervous system, it was also associated with a lower risk of endometrial and testicular cancer.