It is unclear if cafeine consumption is associated with preterm birth or impaired fetal growth. Clausson and coworkers (2002) found no association between moderate cafeine consumption of less than 500 mg/d and low birthweight, fetalgrowth restriction, or preterm delivery. Bech and associates (2007) randomly assigned more than 1200 pregnant women who drank at least three cups of cofee per day to cafeinated versus decafeinated cofee. They found no diference in birthweight or gestational age at delivery between groups. The CARE Study Group (2008), however, evaluated 2635 lowrisk pregnancies and reported a l.4-fold risk for fetal-growth restriction among those whose daily cafeine consumption was >200 mg/d compared with those who consumed <100 mg/d. he American College of Obstetricians and Gynecologists (20e1e6d) concludes that moderate consumption of caffeine-less than 200 mg/ d-does not appear to be associated with miscarriage or preterm birth, but that the relationship between cafeine consumption and fetal-growth restriction remains unsettled. The American Dietetic Association (2008) recommends that cafeine intake during pregnancy be limited to less than 300 mg/d, which approximates three 5-oz cups of percolated cofee.
Nausea and vomiting are common complaints during the first half of pregnancy. These vary in severity and usually commence between the first and second missed menstrual period and continue until 14 to 16 weeks' gestation. Although nausea and vomiting tend to be worse in the morning-thus erroneously termed morning sickness-both symptoms frequently continue throughout the day. Lacroix and coworkers (2000) found that nausea and vomiting were reported by three fourths of pregnant women and lasted an average of35 days. Halfhad reliefby 14 weeks, and 90 percent by 22 weeks. In 80 percent of these women, nausea lasted all day.
Treatment of pregnancy-associated nausea and vomiting seldom provides complete relief, but symptoms can be minimized. Eating small meals at frequent intervals is valuable. One systematic literature search reported that the herbal remedy ginger was likely efective (Borrelli, 2005). Mild symptoms usually respond to vitamin BG given along with doxylamine, but some women require phenothiazine or HI-receptor blocking antiemetics (American College of Obstetricians and Gynecologists, 2015c). In some with hyperemesis gravidarum, vomiting is so severe that dehydration, electrolyte and acid-base disturbances, and starvation ketosis become serious problems.
Heartburn is another common complaint of gravidas and is caused by gastric content reflux into the lower esophagus. The greater frequency of regurgitation during pregnancy most likely results from upward displacement and compression of the stomach by the uterus, combined with relaxation of the lower esophageal sphincter. Avoiding bending over or lying flat is preventive. In most pregnant women, symptoms are mild and relieved by a regimen of more frequent but smaller meals. Antacids may provide considerable relief (Phupong, 2015). Specifically, aluminum hydroxide, magnesium trisilicate, or magnesium hydroxide is given alone or in combination. Management of heartburn or nausea that does not respond to simple measures is discussed in Chapter 54 (p. 1045).