Pregnancy mothers are getting a new tool to help keep themselves and their babies healthy: pregnancy tips sent directly to their cell phones. The so-called text4baby campaign is the first free, health education program in the U.S. to harness the reach of mobile phones, according to its sponsors. Organizers say texting is an effective means of delivering wellness tips because 90 percent of people in the U.S. have cell phones. "Especially if you start talking about low-income people, cell phones are the indispensable tool for reaching them and engaging them about their health," said Paul Meyer, president of Voxiva, a company which operates health texting programs in Africa, Latin America and India. Studies in those countries have shown that periodic texts can reduce smoking and other unhealthy behaviors in pregnant mothers. Meyer said the U.S. program, run by Voxiva, will be the largest health-related texting program ever undertaken. Under the new service, mothers-to-be who text "BABY" to a specified number will receive weekly text messages, timed to their due date or their baby’s birth date. The messages, which have been scanned by government and nonprofit heahlth experts, deal with nutrition, immunization and birth defect prevention, among other topics. The messages will continue through the baby’s first birthday. Text4baby is expected to be announced Thursday morning by officials from the White House’s Office of Science and Technology Policy. Government officials will be publicizing the campaign in speeches and promotional materials. Organizers hope the effort can curb premature (早产的) births, which can be caused by poor nutrition, excessive stress, smoking and drinking alcohol. About 500,000 babies are born prematurely in the U.S. each year. The nonprofit is among the sponsors of the campaign. "The real scary thing is that we’re an industrialized nation and we’re not doing very well on infant death rate, and we know prematurity is a big part of that," said the group’s director, Judy Meehan. Currently the U.S. ranks 30th worldwide for infant death rate, according to Meehan, behind most Western European nations. Researchers at the George Washington University have agreed to evaluate the effectiveness of text4baby by measuring health trends for mothers and newborns. What is the purpose of the Text4baby program

A. To warn women against bad habits.
B. To let people care about prematurity.
C. To improve babies’ nutrition.
D. To reduce infant death rate.